CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available" lang="en" dir="ltr"> <head> <meta charset="UTF-8"> <title>Frequency - Wikipedia</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available";var cookie=document.cookie.match(/(?:^|; )enwikimwclientpreferences=([^;]+)/);if(cookie){cookie[1].split('%2C').forEach(function(pref){className=className.replace(new RegExp('(^| )'+pref.replace(/-clientpref-\w+$|[^\w-]+/g,'')+'-clientpref-\\w+( |$)'),'$1'+pref+'$2');});}document.documentElement.className=className;}());RLCONF={"wgBreakFrames":false,"wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"dmy", "wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgRequestId":"a9198ca7-bc7c-4774-8afc-e40f4aa08f13","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"Frequency","wgTitle":"Frequency","wgCurRevisionId":1258830676,"wgRevisionId":1258830676,"wgArticleId":10779,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["Articles with short description","Short description is different from Wikidata","All articles with unsourced statements","Articles with unsourced statements from April 2024","Articles with unsourced statements from July 2023","Frequency"],"wgPageViewLanguage":"en","wgPageContentLanguage":"en","wgPageContentModel":"wikitext","wgRelevantPageName":"Frequency","wgRelevantArticleId":10779,"wgIsProbablyEditable":true,"wgRelevantPageIsProbablyEditable":true,"wgRestrictionEdit":[],"wgRestrictionMove": [],"wgNoticeProject":"wikipedia","wgCiteReferencePreviewsActive":false,"wgFlaggedRevsParams":{"tags":{"status":{"levels":1}}},"wgMediaViewerOnClick":true,"wgMediaViewerEnabledByDefault":true,"wgPopupsFlags":0,"wgVisualEditor":{"pageLanguageCode":"en","pageLanguageDir":"ltr","pageVariantFallbacks":"en"},"wgMFDisplayWikibaseDescriptions":{"search":true,"watchlist":true,"tagline":false,"nearby":true},"wgWMESchemaEditAttemptStepOversample":false,"wgWMEPageLength":20000,"wgRelatedArticlesCompat":[],"wgCentralAuthMobileDomain":false,"wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage","wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q11652","wgCheckUserClientHintsHeadersJsApi":["brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"],"GEHomepageSuggestedEditsEnableTopics":true,"wgGETopicsMatchModeEnabled":false, "wgGEStructuredTaskRejectionReasonTextInputEnabled":false,"wgGELevelingUpEnabledForUser":false};RLSTATE={"ext.globalCssJs.user.styles":"ready","site.styles":"ready","user.styles":"ready","ext.globalCssJs.user":"ready","user":"ready","user.options":"loading","ext.math.styles":"ready","ext.cite.styles":"ready","skins.vector.search.codex.styles":"ready","skins.vector.styles":"ready","skins.vector.icons":"ready","jquery.makeCollapsible.styles":"ready","ext.wikimediamessages.styles":"ready","ext.visualEditor.desktopArticleTarget.noscript":"ready","ext.uls.interlanguage":"ready","wikibase.client.init":"ready","ext.wikimediaBadges":"ready"};RLPAGEMODULES=["ext.cite.ux-enhancements","ext.math.popup","mediawiki.page.media","ext.scribunto.logs","site","mediawiki.page.ready","jquery.makeCollapsible","mediawiki.toc","skins.vector.js","ext.centralNotice.geoIP","ext.centralNotice.startUp","ext.gadget.ReferenceTooltips","ext.gadget.switcher","ext.urlShortener.toolbar", "ext.centralauth.centralautologin","mmv.bootstrap","ext.popups","ext.visualEditor.desktopArticleTarget.init","ext.visualEditor.targetLoader","ext.echo.centralauth","ext.eventLogging","ext.wikimediaEvents","ext.navigationTiming","ext.uls.interface","ext.cx.eventlogging.campaigns","ext.cx.uls.quick.actions","wikibase.client.vector-2022","ext.checkUser.clientHints","ext.growthExperiments.SuggestedEditSession","wikibase.sidebar.tracking"];</script> <script>(RLQ=window.RLQ||[]).push(function(){mw.loader.impl(function(){return["user.options@12s5i",function($,jQuery,require,module){mw.user.tokens.set({"patrolToken":"+\\","watchToken":"+\\","csrfToken":"+\\"}); }];});});</script> <link rel="stylesheet" href="/w/load.php?lang=en&modules=ext.cite.styles%7Cext.math.styles%7Cext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediaBadges%7Cext.wikimediamessages.styles%7Cjquery.makeCollapsible.styles%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022"> <script async="" src="/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=vector-2022"></script> <meta name="ResourceLoaderDynamicStyles" content=""> <link rel="stylesheet" href="/w/load.php?lang=en&modules=site.styles&only=styles&skin=vector-2022"> <meta name="generator" content="MediaWiki 1.44.0-wmf.4"> <meta name="referrer" content="origin"> <meta name="referrer" content="origin-when-cross-origin"> <meta name="robots" content="max-image-preview:standard"> <meta name="format-detection" content="telephone=no"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/1/1b/%E0%B8%A5%E0%B8%B9%E0%B8%81%E0%B8%95%E0%B8%B8%E0%B9%89%E0%B8%A1%E0%B8%98%E0%B8%A3%E0%B8%A3%E0%B8%A1%E0%B8%8A%E0%B8%B2%E0%B8%95%E0%B8%B4.gif"> <meta property="og:image:width" content="1200"> <meta property="og:image:height" content="900"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/1/1b/%E0%B8%A5%E0%B8%B9%E0%B8%81%E0%B8%95%E0%B8%B8%E0%B9%89%E0%B8%A1%E0%B8%98%E0%B8%A3%E0%B8%A3%E0%B8%A1%E0%B8%8A%E0%B8%B2%E0%B8%95%E0%B8%B4.gif"> <meta property="og:image:width" content="800"> <meta property="og:image:height" content="600"> <meta property="og:image:width" content="640"> <meta property="og:image:height" content="480"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="Frequency - Wikipedia"> <meta property="og:type" content="website"> <link rel="preconnect" href="//upload.wikimedia.org"> <link rel="alternate" media="only screen and (max-width: 640px)" href="//en.m.wikipedia.org/wiki/Frequency"> <link rel="alternate" type="application/x-wiki" title="Edit this page" href="/w/index.php?title=Frequency&action=edit"> <link rel="apple-touch-icon" href="/static/apple-touch/wikipedia.png"> <link rel="icon" href="/static/favicon/wikipedia.ico"> <link rel="search" type="application/opensearchdescription+xml" href="/w/rest.php/v1/search" title="Wikipedia (en)"> <link rel="EditURI" type="application/rsd+xml" href="//en.wikipedia.org/w/api.php?action=rsd"> <link rel="canonical" href="https://en.wikipedia.org/wiki/Frequency"> <link rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en"> <link rel="alternate" type="application/atom+xml" title="Wikipedia Atom feed" href="/w/index.php?title=Special:RecentChanges&feed=atom"> <link rel="dns-prefetch" href="//meta.wikimedia.org" /> <link rel="dns-prefetch" href="//login.wikimedia.org"> </head> <body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject mw-editable page-Frequency rootpage-Frequency skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">Jump to content</a> <div class="vector-header-container"> <header class="vector-header mw-header"> <div class="vector-header-start"> <nav class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-dropdown" class="vector-dropdown vector-main-menu-dropdown vector-button-flush-left vector-button-flush-right" > <input type="checkbox" id="vector-main-menu-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-main-menu-dropdown" class="vector-dropdown-checkbox " aria-label="Main menu" > <label id="vector-main-menu-dropdown-label" for="vector-main-menu-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-menu mw-ui-icon-wikimedia-menu"></span> <span class="vector-dropdown-label-text">Main menu</span> </label> <div class="vector-dropdown-content"> <div id="vector-main-menu-unpinned-container" class="vector-unpinned-container"> <div id="vector-main-menu" class="vector-main-menu vector-pinnable-element"> <div class="vector-pinnable-header vector-main-menu-pinnable-header vector-pinnable-header-unpinned" data-feature-name="main-menu-pinned" data-pinnable-element-id="vector-main-menu" data-pinned-container-id="vector-main-menu-pinned-container" data-unpinned-container-id="vector-main-menu-unpinned-container" > <div class="vector-pinnable-header-label">Main menu</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-main-menu.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-main-menu.unpin">hide</button> </div> <div id="p-navigation" class="vector-menu mw-portlet mw-portlet-navigation" > <div class="vector-menu-heading"> Navigation </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-mainpage-description" class="mw-list-item"><a href="/wiki/Main_Page" title="Visit the main page [z]" accesskey="z"><span>Main page</span></a></li><li id="n-contents" class="mw-list-item"><a href="/wiki/Wikipedia:Contents" title="Guides to browsing Wikipedia"><span>Contents</span></a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/Portal:Current_events" title="Articles related to current events"><span>Current events</span></a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/Special:Random" title="Visit a randomly selected article [x]" accesskey="x"><span>Random article</span></a></li><li id="n-aboutsite" class="mw-list-item"><a href="/wiki/Wikipedia:About" title="Learn about Wikipedia and how it works"><span>About Wikipedia</span></a></li><li id="n-contactpage" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us" title="How to contact Wikipedia"><span>Contact us</span></a></li> </ul> </div> </div> <div id="p-interaction" class="vector-menu mw-portlet mw-portlet-interaction" > <div class="vector-menu-heading"> Contribute </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-help" class="mw-list-item"><a href="/wiki/Help:Contents" title="Guidance on how to use and edit Wikipedia"><span>Help</span></a></li><li id="n-introduction" class="mw-list-item"><a href="/wiki/Help:Introduction" title="Learn how to edit Wikipedia"><span>Learn to edit</span></a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/Wikipedia:Community_portal" title="The hub for editors"><span>Community portal</span></a></li><li id="n-recentchanges" class="mw-list-item"><a href="/wiki/Special:RecentChanges" title="A list of recent changes to Wikipedia [r]" accesskey="r"><span>Recent changes</span></a></li><li id="n-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_upload_wizard" title="Add images or other media for use on Wikipedia"><span>Upload file</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> <a href="/wiki/Main_Page" class="mw-logo"> <img class="mw-logo-icon" src="/static/images/icons/wikipedia.png" alt="" aria-hidden="true" height="50" width="50"> <span class="mw-logo-container skin-invert"> <img class="mw-logo-wordmark" alt="Wikipedia" src="/static/images/mobile/copyright/wikipedia-wordmark-en.svg" style="width: 7.5em; height: 1.125em;"> <img class="mw-logo-tagline" alt="The Free Encyclopedia" src="/static/images/mobile/copyright/wikipedia-tagline-en.svg" width="117" height="13" style="width: 7.3125em; height: 0.8125em;"> </span> </a> </div> <div class="vector-header-end"> <div id="p-search" role="search" class="vector-search-box-vue vector-search-box-collapses vector-search-box-show-thumbnail vector-search-box-auto-expand-width vector-search-box"> <a href="/wiki/Special:Search" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only search-toggle" title="Search Wikipedia [f]" accesskey="f"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </a> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail cdx-typeahead-search--auto-expand-width"> <form action="/w/index.php" id="searchform" class="cdx-search-input cdx-search-input--has-end-button"> <div id="simpleSearch" class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia" aria-label="Search Wikipedia" autocapitalize="sentences" title="Search Wikipedia [f]" accesskey="f" id="searchInput" > <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <nav class="vector-user-links vector-user-links-wide" aria-label="Personal tools"> <div class="vector-user-links-main"> <div id="p-vector-user-menu-preferences" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-userpage" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-dropdown" class="vector-dropdown " title="Change the appearance of the page's font size, width, and color" > <input type="checkbox" id="vector-appearance-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-appearance-dropdown" class="vector-dropdown-checkbox " aria-label="Appearance" > <label id="vector-appearance-dropdown-label" for="vector-appearance-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-appearance mw-ui-icon-wikimedia-appearance"></span> <span class="vector-dropdown-label-text">Appearance</span> </label> <div class="vector-dropdown-content"> <div id="vector-appearance-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div id="p-vector-user-menu-notifications" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-overflow" class="vector-menu mw-portlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en" class=""><span>Donate</span></a> </li> <li id="pt-createaccount-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:CreateAccount&returnto=Frequency" title="You are encouraged to create an account and log in; however, it is not mandatory" class=""><span>Create account</span></a> </li> <li id="pt-login-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:UserLogin&returnto=Frequency" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o" class=""><span>Log in</span></a> </li> </ul> </div> </div> </div> <div id="vector-user-links-dropdown" class="vector-dropdown vector-user-menu vector-button-flush-right vector-user-menu-logged-out" title="Log in and more options" > <input type="checkbox" id="vector-user-links-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-user-links-dropdown" class="vector-dropdown-checkbox " aria-label="Personal tools" > <label id="vector-user-links-dropdown-label" for="vector-user-links-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-ellipsis mw-ui-icon-wikimedia-ellipsis"></span> <span class="vector-dropdown-label-text">Personal tools</span> </label> <div class="vector-dropdown-content"> <div id="p-personal" class="vector-menu mw-portlet mw-portlet-personal user-links-collapsible-item" title="User menu" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport" class="user-links-collapsible-item mw-list-item"><a href="https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en"><span>Donate</span></a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:CreateAccount&returnto=Frequency" title="You are encouraged to create an account and log in; however, it is not mandatory"><span class="vector-icon mw-ui-icon-userAdd mw-ui-icon-wikimedia-userAdd"></span> <span>Create account</span></a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:UserLogin&returnto=Frequency" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o"><span class="vector-icon mw-ui-icon-logIn mw-ui-icon-wikimedia-logIn"></span> <span>Log in</span></a></li> </ul> </div> </div> <div id="p-user-menu-anon-editor" class="vector-menu mw-portlet mw-portlet-user-menu-anon-editor" > <div class="vector-menu-heading"> Pages for logged out editors <a href="/wiki/Help:Introduction" aria-label="Learn more about editing"><span>learn more</span></a> </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-anoncontribs" class="mw-list-item"><a href="/wiki/Special:MyContributions" title="A list of edits made from this IP address [y]" accesskey="y"><span>Contributions</span></a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/Special:MyTalk" title="Discussion about edits from this IP address [n]" accesskey="n"><span>Talk</span></a></li> </ul> </div> </div> </div> </div> </nav> </div> </header> </div> <div class="mw-page-container"> <div class="mw-page-container-inner"> <div class="vector-sitenotice-container"> <div id="siteNotice"></div> </div> <div class="vector-column-start"> <div class="vector-main-menu-container"> <div id="mw-navigation"> <nav id="mw-panel" class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-pinned-container" class="vector-pinned-container"> </div> </nav> </div> </div> <div class="vector-sticky-pinned-container"> <nav id="mw-panel-toc" aria-label="Contents" data-event-name="ui.sidebar-toc" class="mw-table-of-contents-container vector-toc-landmark"> <div id="vector-toc-pinned-container" class="vector-pinned-container"> <div id="vector-toc" class="vector-toc vector-pinnable-element"> <div class="vector-pinnable-header vector-toc-pinnable-header vector-pinnable-header-pinned" data-feature-name="toc-pinned" data-pinnable-element-id="vector-toc" > <h2 class="vector-pinnable-header-label">Contents</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-Definitions_and_units" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Definitions_and_units"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>Definitions and units</span> </div> </a> <ul id="toc-Definitions_and_units-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Period_versus_frequency" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Period_versus_frequency"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Period versus frequency</span> </div> </a> <ul id="toc-Period_versus_frequency-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Related_quantities" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Related_quantities"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Related quantities</span> </div> </a> <ul id="toc-Related_quantities-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-In_wave_propagation" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#In_wave_propagation"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>In wave propagation</span> </div> </a> <ul id="toc-In_wave_propagation-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Measurement" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Measurement"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Measurement</span> </div> </a> <button aria-controls="toc-Measurement-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Measurement subsection</span> </button> <ul id="toc-Measurement-sublist" class="vector-toc-list"> <li id="toc-Counting" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Counting"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.1</span> <span>Counting</span> </div> </a> <ul id="toc-Counting-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Stroboscope" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Stroboscope"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.2</span> <span>Stroboscope</span> </div> </a> <ul id="toc-Stroboscope-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Frequency_counter" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Frequency_counter"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.3</span> <span>Frequency counter</span> </div> </a> <ul id="toc-Frequency_counter-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Heterodyne_methods" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Heterodyne_methods"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.4</span> <span>Heterodyne methods</span> </div> </a> <ul id="toc-Heterodyne_methods-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Examples" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Examples"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Examples</span> </div> </a> <button aria-controls="toc-Examples-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Examples subsection</span> </button> <ul id="toc-Examples-sublist" class="vector-toc-list"> <li id="toc-Light" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Light"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.1</span> <span>Light</span> </div> </a> <ul id="toc-Light-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Sound" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Sound"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.2</span> <span>Sound</span> </div> </a> <ul id="toc-Sound-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Line_current" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Line_current"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.3</span> <span>Line current</span> </div> </a> <ul id="toc-Line_current-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Aperiodic_frequency" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Aperiodic_frequency"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Aperiodic frequency</span> </div> </a> <ul id="toc-Aperiodic_frequency-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Notes" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Notes"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>Notes</span> </div> </a> <ul id="toc-Notes-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">10</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Sources" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Sources"> <div class="vector-toc-text"> <span class="vector-toc-numb">11</span> <span>Sources</span> </div> </a> <ul id="toc-Sources-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Further_reading" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Further_reading"> <div class="vector-toc-text"> <span class="vector-toc-numb">12</span> <span>Further reading</span> </div> </a> <ul id="toc-Further_reading-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">13</span> <span>External links</span> </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">Frequency</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 122 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-122" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">122 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-af mw-list-item"><a href="https://af.wikipedia.org/wiki/Frekwensie" title="Frekwensie – Afrikaans" lang="af" hreflang="af" data-title="Frekwensie" data-language-autonym="Afrikaans" data-language-local-name="Afrikaans" class="interlanguage-link-target"><span>Afrikaans</span></a></li><li class="interlanguage-link interwiki-als mw-list-item"><a href="https://als.wikipedia.org/wiki/Frequenz" title="Frequenz – Alemannic" lang="gsw" hreflang="gsw" data-title="Frequenz" data-language-autonym="Alemannisch" data-language-local-name="Alemannic" class="interlanguage-link-target"><span>Alemannisch</span></a></li><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%AA%D8%B1%D8%AF%D8%AF" title="تردد – Arabic" lang="ar" hreflang="ar" data-title="تردد" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-an mw-list-item"><a href="https://an.wikipedia.org/wiki/Frecuencia" title="Frecuencia – Aragonese" lang="an" hreflang="an" data-title="Frecuencia" data-language-autonym="Aragonés" data-language-local-name="Aragonese" class="interlanguage-link-target"><span>Aragonés</span></a></li><li class="interlanguage-link interwiki-ast mw-list-item"><a href="https://ast.wikipedia.org/wiki/Frecuencia" title="Frecuencia – Asturian" lang="ast" hreflang="ast" data-title="Frecuencia" data-language-autonym="Asturianu" data-language-local-name="Asturian" class="interlanguage-link-target"><span>Asturianu</span></a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/Tezlik" title="Tezlik – Azerbaijani" lang="az" hreflang="az" data-title="Tezlik" data-language-autonym="Azərbaycanca" data-language-local-name="Azerbaijani" class="interlanguage-link-target"><span>Azərbaycanca</span></a></li><li class="interlanguage-link interwiki-azb mw-list-item"><a href="https://azb.wikipedia.org/wiki/%D9%81%D8%B1%DA%A9%D8%A7%D9%86%D8%B3" title="فرکانس – South Azerbaijani" lang="azb" hreflang="azb" data-title="فرکانس" data-language-autonym="تۆرکجه" data-language-local-name="South Azerbaijani" class="interlanguage-link-target"><span>تۆرکجه</span></a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://bn.wikipedia.org/wiki/%E0%A6%95%E0%A6%AE%E0%A7%8D%E0%A6%AA%E0%A6%BE%E0%A6%99%E0%A7%8D%E0%A6%95" title="কম্পাঙ্ক – Bangla" lang="bn" hreflang="bn" data-title="কম্পাঙ্ক" data-language-autonym="বাংলা" data-language-local-name="Bangla" class="interlanguage-link-target"><span>বাংলা</span></a></li><li class="interlanguage-link interwiki-zh-min-nan mw-list-item"><a href="https://zh-min-nan.wikipedia.org/wiki/P%C3%AEn-lu%CC%8Dt" title="Pîn-lu̍t – Minnan" lang="nan" hreflang="nan" data-title="Pîn-lu̍t" data-language-autonym="閩南語 / Bân-lâm-gú" data-language-local-name="Minnan" class="interlanguage-link-target"><span>閩南語 / Bân-lâm-gú</span></a></li><li class="interlanguage-link interwiki-ba mw-list-item"><a href="https://ba.wikipedia.org/wiki/%D0%99%D1%8B%D1%88%D0%BB%D1%8B%D2%A1" title="Йышлыҡ – Bashkir" lang="ba" hreflang="ba" data-title="Йышлыҡ" data-language-autonym="Башҡортса" data-language-local-name="Bashkir" class="interlanguage-link-target"><span>Башҡортса</span></a></li><li class="interlanguage-link interwiki-be mw-list-item"><a href="https://be.wikipedia.org/wiki/%D0%A7%D0%B0%D1%81%D1%82%D0%B0%D1%82%D0%B0" title="Частата – Belarusian" lang="be" hreflang="be" data-title="Частата" data-language-autonym="Беларуская" data-language-local-name="Belarusian" class="interlanguage-link-target"><span>Беларуская</span></a></li><li class="interlanguage-link interwiki-be-x-old mw-list-item"><a href="https://be-tarask.wikipedia.org/wiki/%D0%A7%D0%B0%D1%81%D1%82%D0%B0%D1%81%D1%8C%D1%86%D1%8C" title="Частасьць – Belarusian (Taraškievica orthography)" lang="be-tarask" hreflang="be-tarask" data-title="Частасьць" data-language-autonym="Беларуская (тарашкевіца)" data-language-local-name="Belarusian (Taraškievica orthography)" class="interlanguage-link-target"><span>Беларуская (тарашкевіца)</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%A7%D0%B5%D1%81%D1%82%D0%BE%D1%82%D0%B0" title="Честота – Bulgarian" lang="bg" hreflang="bg" data-title="Честота" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-bar mw-list-item"><a href="https://bar.wikipedia.org/wiki/Frequenz" title="Frequenz – Bavarian" lang="bar" hreflang="bar" data-title="Frequenz" data-language-autonym="Boarisch" data-language-local-name="Bavarian" class="interlanguage-link-target"><span>Boarisch</span></a></li><li class="interlanguage-link interwiki-bs mw-list-item"><a href="https://bs.wikipedia.org/wiki/Frekvencija" title="Frekvencija – Bosnian" lang="bs" hreflang="bs" data-title="Frekvencija" data-language-autonym="Bosanski" data-language-local-name="Bosnian" class="interlanguage-link-target"><span>Bosanski</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Freq%C3%BC%C3%A8ncia" title="Freqüència – Catalan" lang="ca" hreflang="ca" data-title="Freqüència" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cv mw-list-item"><a href="https://cv.wikipedia.org/wiki/%D0%A2%C4%83%D1%82%C4%83%D1%88%D0%BB%C4%83%D1%85" title="Тăтăшлăх – Chuvash" lang="cv" hreflang="cv" data-title="Тăтăшлăх" data-language-autonym="Чӑвашла" data-language-local-name="Chuvash" class="interlanguage-link-target"><span>Чӑвашла</span></a></li><li class="interlanguage-link interwiki-ceb mw-list-item"><a href="https://ceb.wikipedia.org/wiki/Kapila" title="Kapila – Cebuano" lang="ceb" hreflang="ceb" data-title="Kapila" data-language-autonym="Cebuano" data-language-local-name="Cebuano" class="interlanguage-link-target"><span>Cebuano</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Frekvence" title="Frekvence – Czech" lang="cs" hreflang="cs" data-title="Frekvence" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-sn mw-list-item"><a href="https://sn.wikipedia.org/wiki/Rudido" title="Rudido – Shona" lang="sn" hreflang="sn" data-title="Rudido" data-language-autonym="ChiShona" data-language-local-name="Shona" class="interlanguage-link-target"><span>ChiShona</span></a></li><li class="interlanguage-link interwiki-cy mw-list-item"><a href="https://cy.wikipedia.org/wiki/Amledd" title="Amledd – Welsh" lang="cy" hreflang="cy" data-title="Amledd" data-language-autonym="Cymraeg" data-language-local-name="Welsh" class="interlanguage-link-target"><span>Cymraeg</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Frekvens" title="Frekvens – Danish" lang="da" hreflang="da" data-title="Frekvens" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-ary mw-list-item"><a href="https://ary.wikipedia.org/wiki/%D8%AA%D8%B9%D8%A7%D9%88%D9%8A%D8%AF%D8%A9" title="تعاويدة – Moroccan Arabic" lang="ary" hreflang="ary" data-title="تعاويدة" data-language-autonym="الدارجة" data-language-local-name="Moroccan Arabic" class="interlanguage-link-target"><span>الدارجة</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Frequenz" title="Frequenz – German" lang="de" hreflang="de" data-title="Frequenz" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/Sagedus" title="Sagedus – Estonian" lang="et" hreflang="et" data-title="Sagedus" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%A3%CF%85%CF%87%CE%BD%CF%8C%CF%84%CE%B7%CF%84%CE%B1" title="Συχνότητα – Greek" lang="el" hreflang="el" data-title="Συχνότητα" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Frecuencia" title="Frecuencia – Spanish" lang="es" hreflang="es" data-title="Frecuencia" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Frekvenco" title="Frekvenco – Esperanto" lang="eo" hreflang="eo" data-title="Frekvenco" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target"><span>Esperanto</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Maiztasun" title="Maiztasun – Basque" lang="eu" hreflang="eu" data-title="Maiztasun" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%A8%D8%B3%D8%A7%D9%85%D8%AF" title="بسامد – Persian" lang="fa" hreflang="fa" data-title="بسامد" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-hif mw-list-item"><a href="https://hif.wikipedia.org/wiki/Frequency" title="Frequency – Fiji Hindi" lang="hif" hreflang="hif" data-title="Frequency" data-language-autonym="Fiji Hindi" data-language-local-name="Fiji Hindi" class="interlanguage-link-target"><span>Fiji Hindi</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Fr%C3%A9quence" title="Fréquence – French" lang="fr" hreflang="fr" data-title="Fréquence" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-fy mw-list-item"><a href="https://fy.wikipedia.org/wiki/Frekwinsje" title="Frekwinsje – Western Frisian" lang="fy" hreflang="fy" data-title="Frekwinsje" data-language-autonym="Frysk" data-language-local-name="Western Frisian" class="interlanguage-link-target"><span>Frysk</span></a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://ga.wikipedia.org/wiki/Minic%C3%ADocht" title="Minicíocht – Irish" lang="ga" hreflang="ga" data-title="Minicíocht" data-language-autonym="Gaeilge" data-language-local-name="Irish" class="interlanguage-link-target"><span>Gaeilge</span></a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Frecuencia" title="Frecuencia – Galician" lang="gl" hreflang="gl" data-title="Frecuencia" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target"><span>Galego</span></a></li><li class="interlanguage-link interwiki-ki mw-list-item"><a href="https://ki.wikipedia.org/wiki/G%C4%A9thumba" title="Gĩthumba – Kikuyu" lang="ki" hreflang="ki" data-title="Gĩthumba" data-language-autonym="Gĩkũyũ" data-language-local-name="Kikuyu" class="interlanguage-link-target"><span>Gĩkũyũ</span></a></li><li class="interlanguage-link interwiki-gu mw-list-item"><a href="https://gu.wikipedia.org/wiki/%E0%AA%86%E0%AA%B5%E0%AB%83%E0%AA%A4%E0%AB%8D%E0%AA%A4%E0%AA%BF" title="આવૃત્તિ – Gujarati" lang="gu" hreflang="gu" data-title="આવૃત્તિ" data-language-autonym="ગુજરાતી" data-language-local-name="Gujarati" class="interlanguage-link-target"><span>ગુજરાતી</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EC%A7%84%EB%8F%99%EC%88%98" title="진동수 – Korean" lang="ko" hreflang="ko" data-title="진동수" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hy mw-list-item"><a href="https://hy.wikipedia.org/wiki/%D5%80%D5%A1%D5%B3%D5%A1%D5%AD%D5%B8%D6%82%D5%A9%D5%B5%D5%B8%D6%82%D5%B6" title="Հաճախություն – Armenian" lang="hy" hreflang="hy" data-title="Հաճախություն" data-language-autonym="Հայերեն" data-language-local-name="Armenian" class="interlanguage-link-target"><span>Հայերեն</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%86%E0%A4%B5%E0%A5%83%E0%A4%A4%E0%A5%8D%E0%A4%A4%E0%A4%BF" title="आवृत्ति – Hindi" lang="hi" hreflang="hi" data-title="आवृत्ति" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/Frekvencija" title="Frekvencija – Croatian" lang="hr" hreflang="hr" data-title="Frekvencija" data-language-autonym="Hrvatski" data-language-local-name="Croatian" class="interlanguage-link-target"><span>Hrvatski</span></a></li><li class="interlanguage-link interwiki-io mw-list-item"><a href="https://io.wikipedia.org/wiki/Frequenco" title="Frequenco – Ido" lang="io" hreflang="io" data-title="Frequenco" data-language-autonym="Ido" data-language-local-name="Ido" class="interlanguage-link-target"><span>Ido</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Frekuensi" title="Frekuensi – Indonesian" lang="id" hreflang="id" data-title="Frekuensi" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-ia mw-list-item"><a href="https://ia.wikipedia.org/wiki/Frequentia" title="Frequentia – Interlingua" lang="ia" hreflang="ia" data-title="Frequentia" data-language-autonym="Interlingua" data-language-local-name="Interlingua" class="interlanguage-link-target"><span>Interlingua</span></a></li><li class="interlanguage-link interwiki-zu mw-list-item"><a href="https://zu.wikipedia.org/wiki/Umjinge" title="Umjinge – Zulu" lang="zu" hreflang="zu" data-title="Umjinge" data-language-autonym="IsiZulu" data-language-local-name="Zulu" class="interlanguage-link-target"><span>IsiZulu</span></a></li><li class="interlanguage-link interwiki-is mw-list-item"><a href="https://is.wikipedia.org/wiki/T%C3%AD%C3%B0ni" title="Tíðni – Icelandic" lang="is" hreflang="is" data-title="Tíðni" data-language-autonym="Íslenska" data-language-local-name="Icelandic" class="interlanguage-link-target"><span>Íslenska</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Frequenza" title="Frequenza – Italian" lang="it" hreflang="it" data-title="Frequenza" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%AA%D7%93%D7%99%D7%A8%D7%95%D7%AA" title="תדירות – Hebrew" lang="he" hreflang="he" data-title="תדירות" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-ka mw-list-item"><a href="https://ka.wikipedia.org/wiki/%E1%83%A1%E1%83%98%E1%83%AE%E1%83%A8%E1%83%98%E1%83%A0%E1%83%94" title="სიხშირე – Georgian" lang="ka" hreflang="ka" data-title="სიხშირე" data-language-autonym="ქართული" data-language-local-name="Georgian" class="interlanguage-link-target"><span>ქართული</span></a></li><li class="interlanguage-link interwiki-kk mw-list-item"><a href="https://kk.wikipedia.org/wiki/%D0%96%D0%B8%D1%96%D0%BB%D1%96%D0%BA" title="Жиілік – Kazakh" lang="kk" hreflang="kk" data-title="Жиілік" data-language-autonym="Қазақша" data-language-local-name="Kazakh" class="interlanguage-link-target"><span>Қазақша</span></a></li><li class="interlanguage-link interwiki-kw mw-list-item"><a href="https://kw.wikipedia.org/wiki/Menowghedh" title="Menowghedh – Cornish" lang="kw" hreflang="kw" data-title="Menowghedh" data-language-autonym="Kernowek" data-language-local-name="Cornish" class="interlanguage-link-target"><span>Kernowek</span></a></li><li class="interlanguage-link interwiki-sw mw-list-item"><a href="https://sw.wikipedia.org/wiki/Marudio_(fizikia)" title="Marudio (fizikia) – Swahili" lang="sw" hreflang="sw" data-title="Marudio (fizikia)" data-language-autonym="Kiswahili" data-language-local-name="Swahili" class="interlanguage-link-target"><span>Kiswahili</span></a></li><li class="interlanguage-link interwiki-ht mw-list-item"><a href="https://ht.wikipedia.org/wiki/Frekans" title="Frekans – Haitian Creole" lang="ht" hreflang="ht" data-title="Frekans" data-language-autonym="Kreyòl ayisyen" data-language-local-name="Haitian Creole" class="interlanguage-link-target"><span>Kreyòl ayisyen</span></a></li><li class="interlanguage-link interwiki-ku mw-list-item"><a href="https://ku.wikipedia.org/wiki/Frekans" title="Frekans – Kurdish" lang="ku" hreflang="ku" data-title="Frekans" data-language-autonym="Kurdî" data-language-local-name="Kurdish" class="interlanguage-link-target"><span>Kurdî</span></a></li><li class="interlanguage-link interwiki-ky mw-list-item"><a href="https://ky.wikipedia.org/wiki/%D0%96%D1%8B%D1%88%D1%82%D1%8B%D0%BA" title="Жыштык – Kyrgyz" lang="ky" hreflang="ky" data-title="Жыштык" data-language-autonym="Кыргызча" data-language-local-name="Kyrgyz" class="interlanguage-link-target"><span>Кыргызча</span></a></li><li class="interlanguage-link interwiki-la mw-list-item"><a href="https://la.wikipedia.org/wiki/Frequentia" title="Frequentia – Latin" lang="la" hreflang="la" data-title="Frequentia" data-language-autonym="Latina" data-language-local-name="Latin" class="interlanguage-link-target"><span>Latina</span></a></li><li class="interlanguage-link interwiki-lv mw-list-item"><a href="https://lv.wikipedia.org/wiki/Frekvence" title="Frekvence – Latvian" lang="lv" hreflang="lv" data-title="Frekvence" data-language-autonym="Latviešu" data-language-local-name="Latvian" class="interlanguage-link-target"><span>Latviešu</span></a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/Da%C5%BEnis" title="Dažnis – Lithuanian" lang="lt" hreflang="lt" data-title="Dažnis" data-language-autonym="Lietuvių" data-language-local-name="Lithuanian" class="interlanguage-link-target"><span>Lietuvių</span></a></li><li class="interlanguage-link interwiki-lmo mw-list-item"><a href="https://lmo.wikipedia.org/wiki/Frequenza" title="Frequenza – Lombard" lang="lmo" hreflang="lmo" data-title="Frequenza" data-language-autonym="Lombard" data-language-local-name="Lombard" class="interlanguage-link-target"><span>Lombard</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/Frekvencia" title="Frekvencia – Hungarian" lang="hu" hreflang="hu" data-title="Frekvencia" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/%D0%A7%D0%B5%D1%81%D1%82%D0%BE%D1%82%D0%B0" title="Честота – Macedonian" lang="mk" hreflang="mk" data-title="Честота" data-language-autonym="Македонски" data-language-local-name="Macedonian" class="interlanguage-link-target"><span>Македонски</span></a></li><li class="interlanguage-link interwiki-mg mw-list-item"><a href="https://mg.wikipedia.org/wiki/Hatetika" title="Hatetika – Malagasy" lang="mg" hreflang="mg" data-title="Hatetika" data-language-autonym="Malagasy" data-language-local-name="Malagasy" class="interlanguage-link-target"><span>Malagasy</span></a></li><li class="interlanguage-link interwiki-ml mw-list-item"><a href="https://ml.wikipedia.org/wiki/%E0%B4%86%E0%B4%B5%E0%B5%83%E0%B4%A4%E0%B5%8D%E0%B4%A4%E0%B4%BF" title="ആവൃത്തി – Malayalam" lang="ml" hreflang="ml" data-title="ആവൃത്തി" data-language-autonym="മലയാളം" data-language-local-name="Malayalam" class="interlanguage-link-target"><span>മലയാളം</span></a></li><li class="interlanguage-link interwiki-mr mw-list-item"><a href="https://mr.wikipedia.org/wiki/%E0%A4%B5%E0%A4%BE%E0%A4%B0%E0%A4%82%E0%A4%B5%E0%A4%BE%E0%A4%B0%E0%A4%A4%E0%A4%BE" title="वारंवारता – Marathi" lang="mr" hreflang="mr" data-title="वारंवारता" data-language-autonym="मराठी" data-language-local-name="Marathi" class="interlanguage-link-target"><span>मराठी</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Frekuensi" title="Frekuensi – Malay" lang="ms" hreflang="ms" data-title="Frekuensi" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-mn mw-list-item"><a href="https://mn.wikipedia.org/wiki/%D0%94%D0%B0%D0%B2%D1%82%D0%B0%D0%BC%D0%B6" title="Давтамж – Mongolian" lang="mn" hreflang="mn" data-title="Давтамж" data-language-autonym="Монгол" data-language-local-name="Mongolian" class="interlanguage-link-target"><span>Монгол</span></a></li><li class="interlanguage-link interwiki-my mw-list-item"><a href="https://my.wikipedia.org/wiki/%E1%80%80%E1%80%BC%E1%80%AD%E1%80%99%E1%80%BA%E1%80%94%E1%80%BE%E1%80%AF%E1%80%94%E1%80%BA%E1%80%B8" title="ကြိမ်နှုန်း – Burmese" lang="my" hreflang="my" data-title="ကြိမ်နှုန်း" data-language-autonym="မြန်မာဘာသာ" data-language-local-name="Burmese" class="interlanguage-link-target"><span>မြန်မာဘာသာ</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Frequentie" title="Frequentie – Dutch" lang="nl" hreflang="nl" data-title="Frequentie" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-new mw-list-item"><a href="https://new.wikipedia.org/wiki/%E0%A4%AB%E0%A5%8D%E0%A4%B0%E0%A4%BF%E0%A4%95%E0%A5%8D%E0%A4%B5%E0%A5%87%E0%A4%A8%E0%A5%8D%E0%A4%B8%E0%A5%80" title="फ्रिक्वेन्सी – Newari" lang="new" hreflang="new" data-title="फ्रिक्वेन्सी" data-language-autonym="नेपाल भाषा" data-language-local-name="Newari" class="interlanguage-link-target"><span>नेपाल भाषा</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E5%91%A8%E6%B3%A2%E6%95%B0" title="周波数 – Japanese" lang="ja" hreflang="ja" data-title="周波数" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-ce mw-list-item"><a href="https://ce.wikipedia.org/wiki/%D0%9B%D0%B5%D1%81%D1%82%D0%B0%D0%BC" title="Лестам – Chechen" lang="ce" hreflang="ce" data-title="Лестам" data-language-autonym="Нохчийн" data-language-local-name="Chechen" class="interlanguage-link-target"><span>Нохчийн</span></a></li><li class="interlanguage-link interwiki-frr mw-list-item"><a href="https://frr.wikipedia.org/wiki/Frekwens" title="Frekwens – Northern Frisian" lang="frr" hreflang="frr" data-title="Frekwens" data-language-autonym="Nordfriisk" data-language-local-name="Northern Frisian" class="interlanguage-link-target"><span>Nordfriisk</span></a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Frekvens" title="Frekvens – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Frekvens" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Frekvens" title="Frekvens – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="Frekvens" data-language-autonym="Norsk nynorsk" data-language-local-name="Norwegian Nynorsk" class="interlanguage-link-target"><span>Norsk nynorsk</span></a></li><li class="interlanguage-link interwiki-oc mw-list-item"><a href="https://oc.wikipedia.org/wiki/Frequ%C3%A9ncia" title="Frequéncia – Occitan" lang="oc" hreflang="oc" data-title="Frequéncia" data-language-autonym="Occitan" data-language-local-name="Occitan" class="interlanguage-link-target"><span>Occitan</span></a></li><li class="interlanguage-link interwiki-om mw-list-item"><a href="https://om.wikipedia.org/wiki/Frequency" title="Frequency – Oromo" lang="om" hreflang="om" data-title="Frequency" data-language-autonym="Oromoo" data-language-local-name="Oromo" class="interlanguage-link-target"><span>Oromoo</span></a></li><li class="interlanguage-link interwiki-uz mw-list-item"><a href="https://uz.wikipedia.org/wiki/Chastota" title="Chastota – Uzbek" lang="uz" hreflang="uz" data-title="Chastota" data-language-autonym="Oʻzbekcha / ўзбекча" data-language-local-name="Uzbek" class="interlanguage-link-target"><span>Oʻzbekcha / ўзбекча</span></a></li><li class="interlanguage-link interwiki-pa mw-list-item"><a href="https://pa.wikipedia.org/wiki/%E0%A8%AB%E0%A9%8D%E0%A8%B0%E0%A9%80%E0%A8%95%E0%A9%81%E0%A8%90%E0%A8%82%E0%A8%B8%E0%A9%80" title="ਫ੍ਰੀਕੁਐਂਸੀ – Punjabi" lang="pa" hreflang="pa" data-title="ਫ੍ਰੀਕੁਐਂਸੀ" data-language-autonym="ਪੰਜਾਬੀ" data-language-local-name="Punjabi" class="interlanguage-link-target"><span>ਪੰਜਾਬੀ</span></a></li><li class="interlanguage-link interwiki-pnb mw-list-item"><a href="https://pnb.wikipedia.org/wiki/%D9%81%D8%B1%DB%8C%DA%A9%D9%88%D8%A6%DB%8C%D9%86%D8%B3%DB%8C" title="فریکوئینسی – Western Punjabi" lang="pnb" hreflang="pnb" data-title="فریکوئینسی" data-language-autonym="پنجابی" data-language-local-name="Western Punjabi" class="interlanguage-link-target"><span>پنجابی</span></a></li><li class="interlanguage-link interwiki-ps mw-list-item"><a href="https://ps.wikipedia.org/wiki/%D9%81%D8%B1%D9%8A%DA%A9%D9%88%D9%86%D8%B3%D9%8A" title="فريکونسي – Pashto" lang="ps" hreflang="ps" data-title="فريکونسي" data-language-autonym="پښتو" data-language-local-name="Pashto" class="interlanguage-link-target"><span>پښتو</span></a></li><li class="interlanguage-link interwiki-nds mw-list-item"><a href="https://nds.wikipedia.org/wiki/Frequenz" title="Frequenz – Low German" lang="nds" hreflang="nds" data-title="Frequenz" data-language-autonym="Plattdüütsch" data-language-local-name="Low German" class="interlanguage-link-target"><span>Plattdüütsch</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Cz%C4%99stotliwo%C5%9B%C4%87" title="Częstotliwość – Polish" lang="pl" hreflang="pl" data-title="Częstotliwość" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Frequ%C3%AAncia" title="Frequência – Portuguese" lang="pt" hreflang="pt" data-title="Frequência" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Frecven%C8%9B%C4%83" title="Frecvență – Romanian" lang="ro" hreflang="ro" data-title="Frecvență" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-qu mw-list-item"><a href="https://qu.wikipedia.org/wiki/Maywiy_kutinchiq" title="Maywiy kutinchiq – Quechua" lang="qu" hreflang="qu" data-title="Maywiy kutinchiq" data-language-autonym="Runa Simi" data-language-local-name="Quechua" class="interlanguage-link-target"><span>Runa Simi</span></a></li><li class="interlanguage-link interwiki-rue mw-list-item"><a href="https://rue.wikipedia.org/wiki/%D0%A4%D1%80%D0%B5%D0%BA%D0%B2%D0%B5%D0%BD%D1%86%D1%96%D1%8F" title="Фреквенція – Rusyn" lang="rue" hreflang="rue" data-title="Фреквенція" data-language-autonym="Русиньскый" data-language-local-name="Rusyn" class="interlanguage-link-target"><span>Русиньскый</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%A7%D0%B0%D1%81%D1%82%D0%BE%D1%82%D0%B0" title="Частота – Russian" lang="ru" hreflang="ru" data-title="Частота" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-sa mw-list-item"><a href="https://sa.wikipedia.org/wiki/%E0%A4%86%E0%A4%B5%E0%A4%B0%E0%A5%8D%E0%A4%A4%E0%A4%A8%E0%A4%AE%E0%A5%8D_(Frequency)" title="आवर्तनम् (Frequency) – Sanskrit" lang="sa" hreflang="sa" data-title="आवर्तनम् (Frequency)" data-language-autonym="संस्कृतम्" data-language-local-name="Sanskrit" class="interlanguage-link-target"><span>संस्कृतम्</span></a></li><li class="interlanguage-link interwiki-sq mw-list-item"><a href="https://sq.wikipedia.org/wiki/Frekuenca" title="Frekuenca – Albanian" lang="sq" hreflang="sq" data-title="Frekuenca" data-language-autonym="Shqip" data-language-local-name="Albanian" class="interlanguage-link-target"><span>Shqip</span></a></li><li class="interlanguage-link interwiki-scn mw-list-item"><a href="https://scn.wikipedia.org/wiki/Pir%C3%ACudu" title="Pirìudu – Sicilian" lang="scn" hreflang="scn" data-title="Pirìudu" data-language-autonym="Sicilianu" data-language-local-name="Sicilian" class="interlanguage-link-target"><span>Sicilianu</span></a></li><li class="interlanguage-link interwiki-si mw-list-item"><a href="https://si.wikipedia.org/wiki/%E0%B7%83%E0%B6%82%E0%B6%9B%E0%B7%8A%E2%80%8D%E0%B6%BA%E0%B7%8F%E0%B6%AD%E0%B6%BA" title="සංඛ්‍යාතය – Sinhala" lang="si" hreflang="si" data-title="සංඛ්‍යාතය" data-language-autonym="සිංහල" data-language-local-name="Sinhala" class="interlanguage-link-target"><span>සිංහල</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Frequency" title="Frequency – Simple English" lang="en-simple" hreflang="en-simple" data-title="Frequency" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sd mw-list-item"><a href="https://sd.wikipedia.org/wiki/%D9%81%D8%B1%D9%8A%DA%AA%D9%88%D8%A6%D9%86%D8%B3%D9%8A" title="فريڪوئنسي – Sindhi" lang="sd" hreflang="sd" data-title="فريڪوئنسي" data-language-autonym="سنڌي" data-language-local-name="Sindhi" class="interlanguage-link-target"><span>سنڌي</span></a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Frekvencia_(fyzika)" title="Frekvencia (fyzika) – Slovak" lang="sk" hreflang="sk" data-title="Frekvencia (fyzika)" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target"><span>Slovenčina</span></a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/Frekvenca" title="Frekvenca – Slovenian" lang="sl" hreflang="sl" data-title="Frekvenca" data-language-autonym="Slovenščina" data-language-local-name="Slovenian" class="interlanguage-link-target"><span>Slovenščina</span></a></li><li class="interlanguage-link interwiki-ckb mw-list-item"><a href="https://ckb.wikipedia.org/wiki/%D9%84%DB%95%D8%B1%DB%95%D9%84%DB%95%D8%B1" title="لەرەلەر – Central Kurdish" lang="ckb" hreflang="ckb" data-title="لەرەلەر" data-language-autonym="کوردی" data-language-local-name="Central Kurdish" class="interlanguage-link-target"><span>کوردی</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/%D0%A3%D1%87%D0%B5%D1%81%D1%82%D0%B0%D0%BB%D0%BE%D1%81%D1%82" title="Учесталост – Serbian" lang="sr" hreflang="sr" data-title="Учесталост" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-sh mw-list-item"><a href="https://sh.wikipedia.org/wiki/Frekvencija" title="Frekvencija – Serbo-Croatian" lang="sh" hreflang="sh" data-title="Frekvencija" data-language-autonym="Srpskohrvatski / српскохрватски" data-language-local-name="Serbo-Croatian" class="interlanguage-link-target"><span>Srpskohrvatski / српскохрватски</span></a></li><li class="interlanguage-link interwiki-su mw-list-item"><a href="https://su.wikipedia.org/wiki/Fr%C3%A9ku%C3%A9nsi" title="Frékuénsi – Sundanese" lang="su" hreflang="su" data-title="Frékuénsi" data-language-autonym="Sunda" data-language-local-name="Sundanese" class="interlanguage-link-target"><span>Sunda</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Taajuus" title="Taajuus – Finnish" lang="fi" hreflang="fi" data-title="Taajuus" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Frekvens" title="Frekvens – Swedish" lang="sv" hreflang="sv" data-title="Frekvens" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-tl mw-list-item"><a href="https://tl.wikipedia.org/wiki/Dalasan" title="Dalasan – Tagalog" lang="tl" hreflang="tl" data-title="Dalasan" data-language-autonym="Tagalog" data-language-local-name="Tagalog" class="interlanguage-link-target"><span>Tagalog</span></a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikipedia.org/wiki/%E0%AE%85%E0%AE%A4%E0%AE%BF%E0%AE%B0%E0%AF%8D%E0%AE%B5%E0%AF%86%E0%AE%A3%E0%AF%8D" title="அதிர்வெண் – Tamil" lang="ta" hreflang="ta" data-title="அதிர்வெண்" data-language-autonym="தமிழ்" data-language-local-name="Tamil" class="interlanguage-link-target"><span>தமிழ்</span></a></li><li class="interlanguage-link interwiki-tt mw-list-item"><a href="https://tt.wikipedia.org/wiki/%D0%95%D1%88%D0%BB%D1%8B%D0%BA" title="Ешлык – Tatar" lang="tt" hreflang="tt" data-title="Ешлык" data-language-autonym="Татарча / tatarça" data-language-local-name="Tatar" class="interlanguage-link-target"><span>Татарча / tatarça</span></a></li><li class="interlanguage-link interwiki-te mw-list-item"><a href="https://te.wikipedia.org/wiki/%E0%B0%AA%E0%B1%8C%E0%B0%A8%E0%B0%83_%E0%B0%AA%E0%B1%81%E0%B0%A8%E0%B1%8D%E0%B0%AF%E0%B0%AE%E0%B1%81" title="పౌనః పున్యము – Telugu" lang="te" hreflang="te" data-title="పౌనః పున్యము" data-language-autonym="తెలుగు" data-language-local-name="Telugu" class="interlanguage-link-target"><span>తెలుగు</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B8%84%E0%B8%A7%E0%B8%B2%E0%B8%A1%E0%B8%96%E0%B8%B5%E0%B9%88" title="ความถี่ – Thai" lang="th" hreflang="th" data-title="ความถี่" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target"><span>ไทย</span></a></li><li class="interlanguage-link interwiki-tg mw-list-item"><a href="https://tg.wikipedia.org/wiki/%D0%91%D0%B0%D1%81%D0%BE%D0%BC%D0%B0%D0%B4" title="Басомад – Tajik" lang="tg" hreflang="tg" data-title="Басомад" data-language-autonym="Тоҷикӣ" data-language-local-name="Tajik" class="interlanguage-link-target"><span>Тоҷикӣ</span></a></li><li class="interlanguage-link interwiki-chr mw-list-item"><a href="https://chr.wikipedia.org/wiki/%E1%8E%A0%E1%8F%8D%E1%8F%93%E1%8F%A9%E1%8F%9B%E1%8F%8D%E1%8F%99%E1%8F%97" title="ᎠᏍᏓᏩᏛᏍᏙᏗ – Cherokee" lang="chr" hreflang="chr" data-title="ᎠᏍᏓᏩᏛᏍᏙᏗ" data-language-autonym="ᏣᎳᎩ" data-language-local-name="Cherokee" class="interlanguage-link-target"><span>ᏣᎳᎩ</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Frekans" title="Frekans – Turkish" lang="tr" hreflang="tr" data-title="Frekans" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-tk mw-list-item"><a href="https://tk.wikipedia.org/wiki/Tizlik" title="Tizlik – Turkmen" lang="tk" hreflang="tk" data-title="Tizlik" data-language-autonym="Türkmençe" data-language-local-name="Turkmen" class="interlanguage-link-target"><span>Türkmençe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%A7%D0%B0%D1%81%D1%82%D0%BE%D1%82%D0%B0" title="Частота – Ukrainian" lang="uk" hreflang="uk" data-title="Частота" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-ur mw-list-item"><a href="https://ur.wikipedia.org/wiki/%D8%AA%D8%B9%D8%AF%D8%AF" title="تعدد – Urdu" lang="ur" hreflang="ur" data-title="تعدد" data-language-autonym="اردو" data-language-local-name="Urdu" class="interlanguage-link-target"><span>اردو</span></a></li><li class="interlanguage-link interwiki-ug mw-list-item"><a href="https://ug.wikipedia.org/wiki/%DA%86%D8%A7%D8%B3%D8%AA%D9%88%D8%AA%D8%A7" title="چاستوتا – Uyghur" lang="ug" hreflang="ug" data-title="چاستوتا" data-language-autonym="ئۇيغۇرچە / Uyghurche" data-language-local-name="Uyghur" class="interlanguage-link-target"><span>ئۇيغۇرچە / Uyghurche</span></a></li><li class="interlanguage-link interwiki-vec mw-list-item"><a href="https://vec.wikipedia.org/wiki/Frecuensa" title="Frecuensa – Venetian" lang="vec" hreflang="vec" data-title="Frecuensa" data-language-autonym="Vèneto" data-language-local-name="Venetian" class="interlanguage-link-target"><span>Vèneto</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/T%E1%BA%A7n_s%E1%BB%91" title="Tần số – Vietnamese" lang="vi" hreflang="vi" data-title="Tần số" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-war mw-list-item"><a href="https://war.wikipedia.org/wiki/Frekwensiya" title="Frekwensiya – Waray" lang="war" hreflang="war" data-title="Frekwensiya" data-language-autonym="Winaray" data-language-local-name="Waray" class="interlanguage-link-target"><span>Winaray</span></a></li><li class="interlanguage-link interwiki-wo mw-list-item"><a href="https://wo.wikipedia.org/wiki/Baraay" title="Baraay – Wolof" lang="wo" hreflang="wo" data-title="Baraay" data-language-autonym="Wolof" data-language-local-name="Wolof" class="interlanguage-link-target"><span>Wolof</span></a></li><li class="interlanguage-link interwiki-wuu mw-list-item"><a href="https://wuu.wikipedia.org/wiki/%E9%A2%91%E7%8E%87" title="频率 – Wu" lang="wuu" hreflang="wuu" data-title="频率" data-language-autonym="吴语" data-language-local-name="Wu" class="interlanguage-link-target"><span>吴语</span></a></li><li class="interlanguage-link interwiki-yi mw-list-item"><a href="https://yi.wikipedia.org/wiki/%D7%A4%D7%A8%D7%A2%D7%A7%D7%95%D7%95%D7%A2%D7%A0%D7%A5" title="פרעקווענץ – Yiddish" lang="yi" hreflang="yi" data-title="פרעקווענץ" data-language-autonym="ייִדיש" data-language-local-name="Yiddish" class="interlanguage-link-target"><span>ייִדיש</span></a></li><li class="interlanguage-link interwiki-zh-yue mw-list-item"><a href="https://zh-yue.wikipedia.org/wiki/%E9%A0%BB%E7%8E%87" title="頻率 – Cantonese" lang="yue" hreflang="yue" data-title="頻率" data-language-autonym="粵語" data-language-local-name="Cantonese" class="interlanguage-link-target"><span>粵語</span></a></li><li class="interlanguage-link interwiki-bat-smg mw-list-item"><a href="https://bat-smg.wikipedia.org/wiki/Tonk%C4%97nis" title="Tonkėnis – Samogitian" lang="sgs" hreflang="sgs" data-title="Tonkėnis" data-language-autonym="Žemaitėška" data-language-local-name="Samogitian" class="interlanguage-link-target"><span>Žemaitėška</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E9%A0%BB%E7%8E%87_(%E7%89%A9%E7%90%86%E5%AD%B8)" title="頻率 (物理學) – Chinese" lang="zh" hreflang="zh" data-title="頻率 (物理學)" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q11652#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespaces"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-nstab-main" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Frequency" title="View the content page [c]" accesskey="c"><span>Article</span></a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Talk:Frequency" rel="discussion" title="Discuss improvements to the content page [t]" accesskey="t"><span>Talk</span></a></li> </ul> </div> </div> <div id="vector-variants-dropdown" class="vector-dropdown emptyPortlet" > <input type="checkbox" id="vector-variants-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-variants-dropdown" class="vector-dropdown-checkbox " aria-label="Change language variant" > <label id="vector-variants-dropdown-label" for="vector-variants-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">English</span> </label> <div class="vector-dropdown-content"> <div id="p-variants" class="vector-menu mw-portlet mw-portlet-variants emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> </div> </div> </nav> </div> <div id="right-navigation" class="vector-collapsible"> <nav aria-label="Views"> <div id="p-views" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-views" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-view" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Frequency"><span>Read</span></a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Frequency&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Frequency&action=history" title="Past revisions of this page [h]" accesskey="h"><span>View history</span></a></li> </ul> </div> </div> </nav> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-dropdown" class="vector-dropdown vector-page-tools-dropdown" > <input type="checkbox" id="vector-page-tools-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-tools-dropdown" class="vector-dropdown-checkbox " aria-label="Tools" > <label id="vector-page-tools-dropdown-label" for="vector-page-tools-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">Tools</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-tools-unpinned-container" class="vector-unpinned-container"> <div id="vector-page-tools" class="vector-page-tools vector-pinnable-element"> <div class="vector-pinnable-header vector-page-tools-pinnable-header vector-pinnable-header-unpinned" data-feature-name="page-tools-pinned" data-pinnable-element-id="vector-page-tools" data-pinned-container-id="vector-page-tools-pinned-container" data-unpinned-container-id="vector-page-tools-unpinned-container" > <div class="vector-pinnable-header-label">Tools</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-page-tools.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-page-tools.unpin">hide</button> </div> <div id="p-cactions" class="vector-menu mw-portlet mw-portlet-cactions emptyPortlet vector-has-collapsible-items" title="More options" > <div class="vector-menu-heading"> Actions </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-more-view" class="selected vector-more-collapsible-item mw-list-item"><a href="/wiki/Frequency"><span>Read</span></a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Frequency&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Frequency&action=history"><span>View history</span></a></li> </ul> </div> </div> <div id="p-tb" class="vector-menu mw-portlet mw-portlet-tb" > <div class="vector-menu-heading"> General </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-whatlinkshere" class="mw-list-item"><a href="/wiki/Special:WhatLinksHere/Frequency" title="List of all English Wikipedia pages containing links to this page [j]" accesskey="j"><span>What links here</span></a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/Special:RecentChangesLinked/Frequency" rel="nofollow" title="Recent changes in pages linked from this page [k]" accesskey="k"><span>Related changes</span></a></li><li id="t-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_Upload_Wizard" title="Upload files [u]" accesskey="u"><span>Upload file</span></a></li><li id="t-specialpages" class="mw-list-item"><a href="/wiki/Special:SpecialPages" title="A list of all special pages [q]" accesskey="q"><span>Special pages</span></a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=Frequency&oldid=1258830676" title="Permanent link to this revision of this page"><span>Permanent link</span></a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=Frequency&action=info" title="More information about this page"><span>Page information</span></a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=Special:CiteThisPage&page=Frequency&id=1258830676&wpFormIdentifier=titleform" title="Information on how to cite this page"><span>Cite this page</span></a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FFrequency"><span>Get shortened URL</span></a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=Special:QrCode&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FFrequency"><span>Download QR code</span></a></li> </ul> </div> </div> <div id="p-coll-print_export" class="vector-menu mw-portlet mw-portlet-coll-print_export" > <div class="vector-menu-heading"> Print/export </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="coll-download-as-rl" class="mw-list-item"><a href="/w/index.php?title=Special:DownloadAsPdf&page=Frequency&action=show-download-screen" title="Download this page as a PDF file"><span>Download as PDF</span></a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=Frequency&printable=yes" title="Printable version of this page [p]" accesskey="p"><span>Printable version</span></a></li> </ul> </div> </div> <div id="p-wikibase-otherprojects" class="vector-menu mw-portlet mw-portlet-wikibase-otherprojects" > <div class="vector-menu-heading"> In other projects </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="wb-otherproject-link wb-otherproject-commons mw-list-item"><a href="https://commons.wikimedia.org/wiki/Category:Frequency" hreflang="en"><span>Wikimedia Commons</span></a></li><li class="wb-otherproject-link wb-otherproject-wikiversity mw-list-item"><a href="https://en.wikiversity.org/wiki/Frequency" hreflang="en"><span>Wikiversity</span></a></li><li id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q11652" title="Structured data on this page hosted by Wikidata [g]" accesskey="g"><span>Wikidata item</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> </div> </div> </div> <div class="vector-column-end"> <div class="vector-sticky-pinned-container"> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-pinned-container" class="vector-pinned-container"> <div id="vector-appearance" class="vector-appearance vector-pinnable-element"> <div class="vector-pinnable-header vector-appearance-pinnable-header vector-pinnable-header-pinned" data-feature-name="appearance-pinned" data-pinnable-element-id="vector-appearance" data-pinned-container-id="vector-appearance-pinned-container" data-unpinned-container-id="vector-appearance-unpinned-container" > <div class="vector-pinnable-header-label">Appearance</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">hide</button> </div> </div> </div> </nav> </div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Number of occurrences or cycles per unit time</div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">"Frequencies" redirects here. For the film, see <a href="/wiki/Frequencies_(film)" title="Frequencies (film)"><i>Frequencies</i> (film)</a>. For the album, see <a href="/wiki/Frequencies_(album)" title="Frequencies (album)"><i>Frequencies</i> (album)</a>. For other uses, see <a href="/wiki/Frequency_(disambiguation)" class="mw-disambig" title="Frequency (disambiguation)">Frequency (disambiguation)</a>.</div> <style data-mw-deduplicate="TemplateStyles:r1257001546">.mw-parser-output .infobox-subbox{padding:0;border:none;margin:-3px;width:auto;min-width:100%;font-size:100%;clear:none;float:none;background-color:transparent}.mw-parser-output .infobox-3cols-child{margin:auto}.mw-parser-output .infobox .navbar{font-size:100%}@media screen{html.skin-theme-clientpref-night .mw-parser-output .infobox-full-data:not(.notheme)>div:not(.notheme)[style]{background:#1f1f23!important;color:#f8f9fa}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .infobox-full-data:not(.notheme) div:not(.notheme){background:#1f1f23!important;color:#f8f9fa}}@media(min-width:640px){body.skin--responsive .mw-parser-output .infobox-table{display:table!important}body.skin--responsive .mw-parser-output .infobox-table>caption{display:table-caption!important}body.skin--responsive .mw-parser-output .infobox-table>tbody{display:table-row-group}body.skin--responsive .mw-parser-output .infobox-table tr{display:table-row!important}body.skin--responsive .mw-parser-output .infobox-table th,body.skin--responsive .mw-parser-output .infobox-table td{padding-left:inherit;padding-right:inherit}}</style><table class="infobox"><tbody><tr><th colspan="2" class="infobox-above">Frequency</th></tr><tr><td colspan="2" class="infobox-image"><span class="mw-default-size" typeof="mw:File/Frameless"><a href="/wiki/File:%E0%B8%A5%E0%B8%B9%E0%B8%81%E0%B8%95%E0%B8%B8%E0%B9%89%E0%B8%A1%E0%B8%98%E0%B8%A3%E0%B8%A3%E0%B8%A1%E0%B8%8A%E0%B8%B2%E0%B8%95%E0%B8%B4.gif" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/1/1b/%E0%B8%A5%E0%B8%B9%E0%B8%81%E0%B8%95%E0%B8%B8%E0%B9%89%E0%B8%A1%E0%B8%98%E0%B8%A3%E0%B8%A3%E0%B8%A1%E0%B8%8A%E0%B8%B2%E0%B8%95%E0%B8%B4.gif/220px-%E0%B8%A5%E0%B8%B9%E0%B8%81%E0%B8%95%E0%B8%B8%E0%B9%89%E0%B8%A1%E0%B8%98%E0%B8%A3%E0%B8%A3%E0%B8%A1%E0%B8%8A%E0%B8%B2%E0%B8%95%E0%B8%B4.gif" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/1/1b/%E0%B8%A5%E0%B8%B9%E0%B8%81%E0%B8%95%E0%B8%B8%E0%B9%89%E0%B8%A1%E0%B8%98%E0%B8%A3%E0%B8%A3%E0%B8%A1%E0%B8%8A%E0%B8%B2%E0%B8%95%E0%B8%B4.gif 1.5x" data-file-width="300" data-file-height="225" /></a></span><div class="infobox-caption">A <a href="/wiki/Pendulum" title="Pendulum">pendulum</a> making 25 complete <a href="/wiki/Oscillations" class="mw-redirect" title="Oscillations">oscillations</a> in 60 s, a frequency of 0.41<span style="text-decoration:overline;">6</span> <a href="/wiki/Hertz" title="Hertz">Hz</a></div></td></tr><tr><th scope="row" class="infobox-label"><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;">Common symbols</div></th><td class="infobox-data"><span class="texhtml"><i>f</i>, <i>ν</i></span></td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/SI_unit" class="mw-redirect" title="SI unit">SI unit</a></th><td class="infobox-data"><a href="/wiki/Hertz" title="Hertz">hertz</a> (Hz)</td></tr><tr><th scope="row" class="infobox-label"><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;">Other units</div></th><td class="infobox-data"><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style><div class="plainlist"><ul><li>cycle per second (cps)</li><li><a href="/wiki/Revolution_per_minute" class="mw-redirect" title="Revolution per minute">revolution per minute</a> (rpm or r/min)</li></ul></div></td></tr><tr><th scope="row" class="infobox-label">In <a href="/wiki/SI_base_unit" title="SI base unit"><span class="wrap">SI base units</span></a></th><td class="infobox-data"><a href="/wiki/Second" title="Second">s</a><sup>−1</sup></td></tr><tr><th scope="row" class="infobox-label"><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;">Derivations from<br />other quantities</div></th><td class="infobox-data"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"><div class="plainlist"><ul><li><span class="texhtml"><i>f</i> = 1 / <i>T</i></span></li></ul></div></td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Dimensional_analysis#Formulation" title="Dimensional analysis">Dimension</a></th><td class="infobox-data"><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\mathsf {T}}^{-1}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msup> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">T</mi> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mo>−</mo> <mn>1</mn> </mrow> </msup> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle {\mathsf {T}}^{-1}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/93052dac36659d4d2f66e3622a224cf070e83d6f" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:3.916ex; height:2.676ex;" alt="{\displaystyle {\mathsf {T}}^{-1}}"></span></td></tr></tbody></table> <p><b>Frequency</b> (symbol <i>f</i>), most often measured in <i><a href="/wiki/Hertz_(unit)" class="mw-redirect" title="Hertz (unit)">hertz</a></i> (symbol: Hz), is the number of occurrences of a repeating event per <a href="/wiki/Unit_of_time" title="Unit of time">unit of time</a>.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> It is also occasionally referred to as <i>temporal frequency</i> for clarity and to distinguish it from <i><a href="/wiki/Spatial_frequency" title="Spatial frequency">spatial frequency</a></i>. Ordinary frequency is related to <i><a href="/wiki/Angular_frequency" title="Angular frequency">angular frequency</a></i> (symbol <i>ω</i>, with SI unit radian per second) by a factor of 2<a href="/wiki/Pi" title="Pi"><span class="texhtml mvar" style="font-style:italic;">π</span></a>. The <b>period</b> (symbol <i>T</i>) is the interval of time between events, so the period is the <a href="/wiki/Multiplicative_inverse" title="Multiplicative inverse">reciprocal</a> of the frequency: <span class="nowrap"><i>T</i> = 1/<i>f</i></span>.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> </p><p>Frequency is an important parameter used in science and engineering to specify the rate of <a href="/wiki/Oscillation" title="Oscillation">oscillatory</a> and <a href="/wiki/Vibration" title="Vibration">vibratory</a> phenomena, such as mechanical vibrations, <a href="/wiki/Audio_signal" title="Audio signal">audio signals</a> (<a href="/wiki/Sound" title="Sound">sound</a>), <a href="/wiki/Radio_wave" title="Radio wave">radio waves</a>, and <a href="/wiki/Light" title="Light">light</a>. </p><p>For example, if a heart beats at a frequency of 120 times per minute (2 hertz), the period—the time interval between beats—is half a second (60 seconds divided by 120). </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Definitions_and_units">Definitions and units <span class="anchor" id="Definitions"></span><span class="anchor" id="Units"></span><span class="anchor" id="Definition"></span><span class="anchor" id="Unit"></span></h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=1" title="Edit section: Definitions and units"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Pendulum-no-text.gif" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Pendulum-no-text.gif/220px-Pendulum-no-text.gif" decoding="async" width="220" height="216" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Pendulum-no-text.gif/330px-Pendulum-no-text.gif 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Pendulum-no-text.gif/440px-Pendulum-no-text.gif 2x" data-file-width="600" data-file-height="590" /></a><figcaption>A <a href="/wiki/Pendulum" title="Pendulum">pendulum</a> with a period of 2.8 s and a frequency of 0.36 <a href="/wiki/Hertz" title="Hertz">Hz</a></figcaption></figure> <p>For cyclical phenomena such as <a href="/wiki/Oscillation" title="Oscillation">oscillations</a>, <a href="/wiki/Wave" title="Wave">waves</a>, or for examples of <a href="/wiki/Simple_harmonic_motion" title="Simple harmonic motion">simple harmonic motion</a>, the term <i>frequency</i> is defined as the number of cycles or repetitions per unit of time. The conventional symbol for frequency is <i>f</i> or <i>ν</i> (the Greek letter <a href="/wiki/Nu_(letter)" title="Nu (letter)">nu</a>) is also used.<sup id="cite_ref-FOOTNOTESerwayFaughn1989346_3-0" class="reference"><a href="#cite_note-FOOTNOTESerwayFaughn1989346-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> The <i>period</i> <i>T</i> is the time taken to complete one cycle of an oscillation or rotation. The frequency and the period are related by the equation<sup id="cite_ref-FOOTNOTESerwayFaughn1989354_4-0" class="reference"><a href="#cite_note-FOOTNOTESerwayFaughn1989354-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> <span class="mwe-math-element" data-qid="Q11652"><a href="/w/index.php?title=Special:MathWikibase&qid=Q11652" style="color:inherit;"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle f={\frac {1}{T}}.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>f</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mi>T</mi> </mfrac> </mrow> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle f={\frac {1}{T}}.}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/01d0a6b6ad677166ddf5f54f8782bbe74b6890ae" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:7.496ex; height:5.176ex;" alt="{\displaystyle f={\frac {1}{T}}.}"></a></span> </p><p>The term <i>temporal frequency</i> is used to emphasise that the frequency is characterised by the number of occurrences of a repeating event per unit time. </p><p>The <a href="/wiki/SI" class="mw-redirect" title="SI">SI</a> unit of frequency is the <a href="/wiki/Hertz" title="Hertz">hertz</a> (Hz),<sup id="cite_ref-FOOTNOTESerwayFaughn1989354_4-1" class="reference"><a href="#cite_note-FOOTNOTESerwayFaughn1989354-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> named after the German physicist <a href="/wiki/Heinrich_Hertz" title="Heinrich Hertz">Heinrich Hertz</a> by the <a href="/wiki/International_Electrotechnical_Commission" title="International Electrotechnical Commission">International Electrotechnical Commission</a> in 1930. It was adopted by the <a href="/wiki/CGPM" class="mw-redirect" title="CGPM">CGPM</a> (Conférence générale des poids et mesures) in 1960, officially replacing the previous name, <i><a href="/wiki/Cycle_per_second" title="Cycle per second">cycle per second</a></i> (cps). The SI unit for the period, as for all measurements of time, is the <a href="/wiki/Second" title="Second">second</a>.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> A traditional unit of frequency used with rotating mechanical devices, where it is termed <i><a href="/wiki/Rotational_frequency" title="Rotational frequency">rotational frequency</a></i>, is <a href="/wiki/Revolution_per_minute" class="mw-redirect" title="Revolution per minute">revolution per minute</a>, abbreviated r/min or rpm.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> 60 rpm is equivalent to one hertz.<sup id="cite_ref-FOOTNOTEDavies1997275_7-0" class="reference"><a href="#cite_note-FOOTNOTEDavies1997275-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Period_versus_frequency">Period versus frequency</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=2" title="Edit section: Period versus frequency"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>As a matter of convenience, longer and slower waves, such as <a href="/wiki/Ocean_surface_wave" class="mw-redirect" title="Ocean surface wave">ocean surface waves</a>, are more typically described by wave period rather than frequency.<sup id="cite_ref-FOOTNOTEYoung19997_8-0" class="reference"><a href="#cite_note-FOOTNOTEYoung19997-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> Short and fast waves, like <a href="/wiki/Sound" title="Sound">audio</a> and radio, are usually described by their frequency. Some commonly used conversions are listed below: </p> <table class="wikitable"> <tbody><tr> <th>Frequency </th> <th>Period </th></tr> <tr> <td>1 mHz (10<sup>−3</sup> Hz) </td> <td>1 ks (10<sup>3</sup> s) </td></tr> <tr> <td>1 Hz (10<sup>0</sup> Hz) </td> <td>1 s (10<sup>0</sup> s) </td></tr> <tr> <td>1 kHz (10<sup>3</sup> Hz) </td> <td>1 ms (10<sup>−3</sup> s) </td></tr> <tr> <td>1 MHz (10<sup>6</sup> Hz) </td> <td>1 μs (10<sup>−6</sup> s) </td></tr> <tr> <td>1 GHz (10<sup>9</sup> Hz) </td> <td>1 ns (10<sup>−9</sup> s) </td></tr> <tr> <td>1 THz (10<sup>12</sup> Hz) </td> <td>1 ps (10<sup>−12</sup> s) </td></tr> </tbody></table> <div class="mw-heading mw-heading2"><h2 id="Related_quantities">Related quantities</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=3" title="Edit section: Related quantities"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Commutative_diagram_of_harmonic_wave_properties.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Commutative_diagram_of_harmonic_wave_properties.svg/220px-Commutative_diagram_of_harmonic_wave_properties.svg.png" decoding="async" width="220" height="276" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Commutative_diagram_of_harmonic_wave_properties.svg/330px-Commutative_diagram_of_harmonic_wave_properties.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Commutative_diagram_of_harmonic_wave_properties.svg/440px-Commutative_diagram_of_harmonic_wave_properties.svg.png 2x" data-file-width="689" data-file-height="864" /></a><figcaption>Diagram of the relationship between the different types of frequency and other wave properties. In this diagram, <i>x</i> is the input to the function represented by the arrow.</figcaption></figure> <ul><li><a href="/wiki/Rotational_frequency" title="Rotational frequency">Rotational frequency</a>, usually denoted by the Greek letter <a href="/wiki/Nu_(letter)" title="Nu (letter)"><i>ν</i></a> (nu), is defined as the instantaneous rate of change of the <a href="/wiki/Number_of_rotations" class="mw-redirect" title="Number of rotations">number of rotations</a>, <i>N</i>, with respect to time: <span class="nowrap"><i>ν</i> = d<i>N</i>/d<i>t</i>;</span> it is a type of frequency applied to <a href="/wiki/Rotational_motion" class="mw-redirect" title="Rotational motion">rotational motion</a>.</li> <li><a href="/wiki/Angular_frequency" title="Angular frequency">Angular frequency</a>, usually denoted by the Greek letter <a href="/wiki/Omega_(letter)" class="mw-redirect" title="Omega (letter)"><i>ω</i></a> (omega), is defined as the rate of change of <a href="/wiki/Angular_displacement" title="Angular displacement">angular displacement</a> (during rotation), <a href="/wiki/Theta" title="Theta"><i>θ</i></a> (theta), or the rate of change of the <a href="/wiki/Phase_(waves)" title="Phase (waves)">phase</a> of a <a href="/wiki/Sine_wave" title="Sine wave">sinusoidal</a> waveform (notably in oscillations and waves), or as the rate of change of the <a href="/wiki/Argument_of_a_function" title="Argument of a function">argument</a> to the <a href="/wiki/Sine_function" class="mw-redirect" title="Sine function">sine function</a>:</li></ul> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle y(t)=\sin \theta (t)=\sin(\omega t)=\sin(2\mathrm {\pi } ft)}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>y</mi> <mo stretchy="false">(</mo> <mi>t</mi> <mo stretchy="false">)</mo> <mo>=</mo> <mi>sin</mi> <mo>⁡</mo> <mi>θ</mi> <mo stretchy="false">(</mo> <mi>t</mi> <mo stretchy="false">)</mo> <mo>=</mo> <mi>sin</mi> <mo>⁡</mo> <mo stretchy="false">(</mo> <mi>ω</mi> <mi>t</mi> <mo stretchy="false">)</mo> <mo>=</mo> <mi>sin</mi> <mo>⁡</mo> <mo stretchy="false">(</mo> <mn>2</mn> <mrow class="MJX-TeXAtom-ORD"> <mi>π</mi> </mrow> <mi>f</mi> <mi>t</mi> <mo stretchy="false">)</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle y(t)=\sin \theta (t)=\sin(\omega t)=\sin(2\mathrm {\pi } ft)}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/45524af174b06aad8c581e853b8368e4bc09783e" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:36.31ex; height:2.843ex;" alt="{\displaystyle y(t)=\sin \theta (t)=\sin(\omega t)=\sin(2\mathrm {\pi } ft)}"></span> <span class="mwe-math-element" data-qid="Q161635"><a href="/w/index.php?title=Special:MathWikibase&qid=Q161635" style="color:inherit;"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\frac {\mathrm {d} \theta }{\mathrm {d} t}}=\omega =2\mathrm {\pi } f.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">d</mi> </mrow> <mi>θ</mi> </mrow> <mrow> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">d</mi> </mrow> <mi>t</mi> </mrow> </mfrac> </mrow> <mo>=</mo> <mi>ω</mi> <mo>=</mo> <mn>2</mn> <mrow class="MJX-TeXAtom-ORD"> <mi>π</mi> </mrow> <mi>f</mi> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle {\frac {\mathrm {d} \theta }{\mathrm {d} t}}=\omega =2\mathrm {\pi } f.}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/205b0665c12fb880734dc68dc3ea72a1bbcb89be" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.005ex; width:15.282ex; height:5.509ex;" alt="{\displaystyle {\frac {\mathrm {d} \theta }{\mathrm {d} t}}=\omega =2\mathrm {\pi } f.}"></a></span></dd> <dd>The unit of angular frequency is the <a href="/wiki/Radian" title="Radian">radian</a> per second (rad/s) but, for <a href="/wiki/Discrete-time_signal" class="mw-redirect" title="Discrete-time signal">discrete-time signals</a>, can also be expressed as radians per <a href="/wiki/Sampling_interval" class="mw-redirect" title="Sampling interval">sampling interval</a>, which is a <a href="/wiki/Dimensionless_quantity" title="Dimensionless quantity">dimensionless quantity</a>. Angular frequency is frequency multiplied by 2<span class="texhtml mvar" style="font-style:italic;">π</span>.</dd></dl> <ul><li><a href="/wiki/Spatial_frequency" title="Spatial frequency">Spatial frequency</a>, denoted here by <i><a href="/wiki/%CE%9E" class="mw-redirect" title="Ξ">ξ</a></i> (xi), is analogous to temporal frequency, but with a spatial measurement replacing time measurement,<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>note 1<span class="cite-bracket">]</span></a></sup> e.g.: <span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle y(t)=\sin \theta (t,x)=\sin(\omega t+kx)}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>y</mi> <mo stretchy="false">(</mo> <mi>t</mi> <mo stretchy="false">)</mo> <mo>=</mo> <mi>sin</mi> <mo>⁡</mo> <mi>θ</mi> <mo stretchy="false">(</mo> <mi>t</mi> <mo>,</mo> <mi>x</mi> <mo stretchy="false">)</mo> <mo>=</mo> <mi>sin</mi> <mo>⁡</mo> <mo stretchy="false">(</mo> <mi>ω</mi> <mi>t</mi> <mo>+</mo> <mi>k</mi> <mi>x</mi> <mo stretchy="false">)</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle y(t)=\sin \theta (t,x)=\sin(\omega t+kx)}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/b655c5fe57d0d3dd9c40d38d0cfe2e161e020c8d" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:31.679ex; height:2.843ex;" alt="{\displaystyle y(t)=\sin \theta (t,x)=\sin(\omega t+kx)}"></span> <span class="mwe-math-element" data-qid="Q192510"><a href="/w/index.php?title=Special:MathWikibase&qid=Q192510" style="color:inherit;"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\frac {\mathrm {d} \theta }{\mathrm {d} x}}=k=2\pi \xi .}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">d</mi> </mrow> <mi>θ</mi> </mrow> <mrow> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">d</mi> </mrow> <mi>x</mi> </mrow> </mfrac> </mrow> <mo>=</mo> <mi>k</mi> <mo>=</mo> <mn>2</mn> <mi>π</mi> <mi>ξ</mi> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle {\frac {\mathrm {d} \theta }{\mathrm {d} x}}=k=2\pi \xi .}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/f7f549b4dbf3229f90e1f10f3a139091c7eadd7c" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.005ex; width:15.038ex; height:5.509ex;" alt="{\displaystyle {\frac {\mathrm {d} \theta }{\mathrm {d} x}}=k=2\pi \xi .}"></a></span> <ul><li><a href="/wiki/Spatial_period" class="mw-redirect" title="Spatial period">Spatial period</a> or wavelength is the spatial analog to temporal period.</li></ul></li></ul> <div class="mw-heading mw-heading2"><h2 id="In_wave_propagation">In wave propagation <span class="anchor" id="Frequency_of_waves"></span></h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=4" title="Edit section: In wave propagation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Further information: <a href="/wiki/Wave_propagation" class="mw-redirect" title="Wave propagation">Wave propagation</a></div> <p>For periodic waves in <a href="/wiki/Dispersion_relation" title="Dispersion relation">nondispersive media</a> (that is, media in which the wave speed is independent of frequency), frequency has an inverse relationship to the <a href="/wiki/Wavelength" title="Wavelength">wavelength</a>, <i>λ</i> (<a href="/wiki/Lambda" title="Lambda">lambda</a>). Even in dispersive media, the frequency <i>f</i> of a <a href="/wiki/Sine_wave" title="Sine wave">sinusoidal wave</a> is equal to the <a href="/wiki/Phase_velocity" title="Phase velocity">phase velocity</a> <i>v</i> of the wave <a href="/wiki/Division_(mathematics)" title="Division (mathematics)">divided</a> by the wavelength <i>λ</i> of the wave: <span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle f={\frac {v}{\lambda }}.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>f</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>v</mi> <mi>λ</mi> </mfrac> </mrow> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle f={\frac {v}{\lambda }}.}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/888f09904f5fa6e98f3e7dee005f1696c09910c0" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.005ex; width:7.215ex; height:4.843ex;" alt="{\displaystyle f={\frac {v}{\lambda }}.}"></span> </p><p>In the <a href="/wiki/Special_case" title="Special case">special case</a> of electromagnetic waves in <a href="/wiki/Vacuum" title="Vacuum">vacuum</a>, then <span class="nowrap"><i>v</i> = <i>c</i></span>, where <i>c</i> is the <a href="/wiki/Speed_of_light" title="Speed of light">speed of light</a> in vacuum, and this expression becomes <span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle f={\frac {c}{\lambda }}.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>f</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>c</mi> <mi>λ</mi> </mfrac> </mrow> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle f={\frac {c}{\lambda }}.}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/8c478df44b1179ad1b63bc286e0f247b859db5d9" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.005ex; width:7.215ex; height:4.843ex;" alt="{\displaystyle f={\frac {c}{\lambda }}.}"></span> </p><p>When <a href="/wiki/Monochromatic_radiation" title="Monochromatic radiation">monochromatic waves</a> travel from one <a href="/wiki/Medium_(optics)" class="mw-redirect" title="Medium (optics)">medium</a> to another, their frequency remains the same—only their wavelength and <a href="/wiki/Phase_speed" class="mw-redirect" title="Phase speed">speed</a> change. </p> <div class="mw-heading mw-heading2"><h2 id="Measurement">Measurement</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=5" title="Edit section: Measurement"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/Frequency_meter" title="Frequency meter">Frequency meter</a></div> <p>Measurement of frequency can be done in the following ways: </p> <div class="mw-heading mw-heading3"><h3 id="Counting">Counting</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=6" title="Edit section: Counting"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Calculating the frequency of a repeating event is accomplished by counting the number of times that event occurs within a specific time period, then dividing the count by the period. For example, if 71 events occur within 15 seconds the frequency is: <span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle f={\frac {71}{15\,{\text{s}}}}\approx 4.73\,{\text{Hz}}.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>f</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>71</mn> <mrow> <mn>15</mn> <mspace width="thinmathspace" /> <mrow class="MJX-TeXAtom-ORD"> <mtext>s</mtext> </mrow> </mrow> </mfrac> </mrow> <mo>≈</mo> <mn>4.73</mn> <mspace width="thinmathspace" /> <mrow class="MJX-TeXAtom-ORD"> <mtext>Hz</mtext> </mrow> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle f={\frac {71}{15\,{\text{s}}}}\approx 4.73\,{\text{Hz}}.}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/57f7e18bffda1c9ffdf7eb5733672b8de9f381f9" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:19.884ex; height:5.176ex;" alt="{\displaystyle f={\frac {71}{15\,{\text{s}}}}\approx 4.73\,{\text{Hz}}.}"></span> If the number of counts is not very large, it is more accurate to measure the time interval for a predetermined number of occurrences, rather than the number of occurrences within a specified time.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (April 2024)">citation needed</span></a></i>]</sup> The latter method introduces a <a href="/wiki/Random_error" class="mw-redirect" title="Random error">random error</a> into the count of between zero and one count, so on <a href="/wiki/Average" title="Average">average</a> half a count. This is called <i>gating error</i> and causes an average error in the calculated frequency of <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\textstyle \Delta f={\frac {1}{2T_{\text{m}}}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="false" scriptlevel="0"> <mi mathvariant="normal">Δ</mi> <mi>f</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mrow> <mn>2</mn> <msub> <mi>T</mi> <mrow class="MJX-TeXAtom-ORD"> <mtext>m</mtext> </mrow> </msub> </mrow> </mfrac> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\textstyle \Delta f={\frac {1}{2T_{\text{m}}}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/66e74b667ed2dd759d869c2cba88ae905c2c2cdc" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.505ex; width:10.207ex; height:3.843ex;" alt="{\textstyle \Delta f={\frac {1}{2T_{\text{m}}}}}"></span>, or a fractional error of <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\textstyle {\frac {\Delta f}{f}}={\frac {1}{2fT_{\text{m}}}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="false" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mi mathvariant="normal">Δ</mi> <mi>f</mi> </mrow> <mi>f</mi> </mfrac> </mrow> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mrow> <mn>2</mn> <mi>f</mi> <msub> <mi>T</mi> <mrow class="MJX-TeXAtom-ORD"> <mtext>m</mtext> </mrow> </msub> </mrow> </mfrac> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\textstyle {\frac {\Delta f}{f}}={\frac {1}{2fT_{\text{m}}}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/97eaa9cc148ebae9308585211b78c29a26e0ab70" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.671ex; width:11.005ex; height:4.509ex;" alt="{\textstyle {\frac {\Delta f}{f}}={\frac {1}{2fT_{\text{m}}}}}"></span> where <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle T_{\text{m}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>T</mi> <mrow class="MJX-TeXAtom-ORD"> <mtext>m</mtext> </mrow> </msub> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle T_{\text{m}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/ec5e24395517d85782d6d98612875ee34553e136" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.959ex; height:2.509ex;" alt="{\displaystyle T_{\text{m}}}"></span> is the timing interval and <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle f}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>f</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle f}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/132e57acb643253e7810ee9702d9581f159a1c61" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:1.279ex; height:2.509ex;" alt="{\displaystyle f}"></span> is the measured frequency. This error decreases with frequency, so it is generally a problem at low frequencies where the number of counts <i>N</i> is small. </p> <style data-mw-deduplicate="TemplateStyles:r1237032888/mw-parser-output/.tmulti">.mw-parser-output .tmulti .multiimageinner{display:flex;flex-direction:column}.mw-parser-output .tmulti .trow{display:flex;flex-direction:row;clear:left;flex-wrap:wrap;width:100%;box-sizing:border-box}.mw-parser-output .tmulti .tsingle{margin:1px;float:left}.mw-parser-output .tmulti .theader{clear:both;font-weight:bold;text-align:center;align-self:center;background-color:transparent;width:100%}.mw-parser-output .tmulti .thumbcaption{background-color:transparent}.mw-parser-output .tmulti .text-align-left{text-align:left}.mw-parser-output .tmulti .text-align-right{text-align:right}.mw-parser-output .tmulti .text-align-center{text-align:center}@media all and (max-width:720px){.mw-parser-output .tmulti .thumbinner{width:100%!important;box-sizing:border-box;max-width:none!important;align-items:center}.mw-parser-output .tmulti .trow{justify-content:center}.mw-parser-output .tmulti .tsingle{float:none!important;max-width:100%!important;box-sizing:border-box;text-align:center}.mw-parser-output .tmulti .tsingle .thumbcaption{text-align:left}.mw-parser-output .tmulti .trow>.thumbcaption{text-align:center}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .tmulti .multiimageinner img{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .tmulti .multiimageinner img{background-color:white}}</style><div class="thumb tmulti tright"><div class="thumbinner multiimageinner" style="width:304px;max-width:304px"><div class="trow"><div class="tsingle" style="width:302px;max-width:302px"><div class="thumbimage"><span typeof="mw:File"><a href="/wiki/File:Resonant_reed_frequency_meter.jpg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/d/d0/Resonant_reed_frequency_meter.jpg/300px-Resonant_reed_frequency_meter.jpg" decoding="async" width="300" height="158" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/d0/Resonant_reed_frequency_meter.jpg/450px-Resonant_reed_frequency_meter.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/d0/Resonant_reed_frequency_meter.jpg/600px-Resonant_reed_frequency_meter.jpg 2x" data-file-width="1784" data-file-height="940" /></a></span></div></div></div><div class="trow"><div class="tsingle" style="width:302px;max-width:302px"><div class="thumbimage"><span typeof="mw:File"><a href="/wiki/File:Czestosciomierz-49.9Hz.jpg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/8/81/Czestosciomierz-49.9Hz.jpg/300px-Czestosciomierz-49.9Hz.jpg" decoding="async" width="300" height="157" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/81/Czestosciomierz-49.9Hz.jpg/450px-Czestosciomierz-49.9Hz.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/81/Czestosciomierz-49.9Hz.jpg/600px-Czestosciomierz-49.9Hz.jpg 2x" data-file-width="1804" data-file-height="947" /></a></span></div></div></div><div class="trow" style="display:flex"><div class="thumbcaption">A resonant-reed frequency meter, an obsolete device used from about 1900 to the 1940s for measuring the frequency of alternating current. It consists of a strip of metal with reeds of graduated lengths, vibrated by an <a href="/wiki/Electromagnet" title="Electromagnet">electromagnet</a>. When the unknown frequency is applied to the electromagnet, the reed which is <a href="/wiki/Resonance" title="Resonance">resonant</a> at that frequency will vibrate with large amplitude, visible next to the scale.</div></div></div></div> <div class="mw-heading mw-heading3"><h3 id="Stroboscope">Stroboscope</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=7" title="Edit section: Stroboscope"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>An old method of measuring the frequency of rotating or vibrating objects is to use a <a href="/wiki/Stroboscope" title="Stroboscope">stroboscope</a>. This is an intense repetitively flashing light (<a href="/wiki/Strobe_light" title="Strobe light">strobe light</a>) whose frequency can be adjusted with a calibrated timing circuit. The strobe light is pointed at the rotating object and the frequency adjusted up and down. When the frequency of the strobe equals the frequency of the rotating or vibrating object, the object completes one cycle of oscillation and returns to its original position between the flashes of light, so when illuminated by the strobe the object appears stationary. Then the frequency can be read from the calibrated readout on the stroboscope. A downside of this method is that an object rotating at an integer multiple of the strobing frequency will also appear stationary. </p> <div class="mw-heading mw-heading3"><h3 id="Frequency_counter">Frequency counter</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=8" title="Edit section: Frequency counter"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Frequency_counter" title="Frequency counter">Frequency counter</a></div> <figure class="mw-default-size mw-halign-left" typeof="mw:File/Thumb"><a href="/wiki/File:Frequency_counter.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/5/59/Frequency_counter.jpg/220px-Frequency_counter.jpg" decoding="async" width="220" height="95" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/59/Frequency_counter.jpg/330px-Frequency_counter.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/59/Frequency_counter.jpg/440px-Frequency_counter.jpg 2x" data-file-width="1809" data-file-height="780" /></a><figcaption>Modern frequency counter</figcaption></figure> <p>Higher frequencies are usually measured with a <a href="/wiki/Frequency_counter" title="Frequency counter">frequency counter</a>. This is an <a href="/wiki/Electronic_instrumentation" class="mw-redirect" title="Electronic instrumentation">electronic instrument</a> which measures the frequency of an applied repetitive electronic <a href="/wiki/Signal_(electronics)" class="mw-redirect" title="Signal (electronics)">signal</a> and displays the result in hertz on a <a href="/wiki/Digital_display" class="mw-redirect" title="Digital display">digital display</a>. It uses <a href="/wiki/Digital_logic" class="mw-redirect" title="Digital logic">digital logic</a> to count the number of cycles during a time interval established by a precision <a href="/wiki/Quartz_clock" title="Quartz clock">quartz</a> time base. Cyclic processes that are not electrical, such as the rotation rate of a shaft, mechanical vibrations, or <a href="/wiki/Sound_wave" class="mw-redirect" title="Sound wave">sound waves</a>, can be converted to a repetitive electronic signal by <a href="/wiki/Transducer" title="Transducer">transducers</a> and the signal applied to a frequency counter. As of 2018, frequency counters can cover the range up to about 100 GHz. This represents the limit of direct counting methods; frequencies above this must be measured by indirect methods. </p> <div class="mw-heading mw-heading3"><h3 id="Heterodyne_methods">Heterodyne methods</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=9" title="Edit section: Heterodyne methods"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Above the range of frequency counters, frequencies of electromagnetic signals are often measured indirectly utilizing <a href="/wiki/Heterodyning" class="mw-redirect" title="Heterodyning">heterodyning</a> (<a href="/wiki/Frequency_changer" title="Frequency changer">frequency conversion</a>). A reference signal of a known frequency near the unknown frequency is mixed with the unknown frequency in a nonlinear mixing device such as a <a href="/wiki/Diode" title="Diode">diode</a>. This creates a <a href="/wiki/Heterodyne" title="Heterodyne">heterodyne</a> or "beat" signal at the difference between the two frequencies. If the two signals are close together in frequency the heterodyne is low enough to be measured by a frequency counter. This process only measures the difference between the unknown frequency and the reference frequency. To convert higher frequencies, several stages of heterodyning can be used. Current research is extending this method to infrared and light frequencies (<a href="/wiki/Optical_heterodyne_detection" title="Optical heterodyne detection">optical heterodyne detection</a>). </p> <div class="mw-heading mw-heading2"><h2 id="Examples">Examples</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=10" title="Edit section: Examples"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Light">Light</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=11" title="Edit section: Light"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main articles: <a href="/wiki/Light" title="Light">Light</a> and <a href="/wiki/Electromagnetic_radiation" title="Electromagnetic radiation">Electromagnetic radiation</a></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:EM_spectrum.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f1/EM_spectrum.svg/440px-EM_spectrum.svg.png" decoding="async" width="440" height="209" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f1/EM_spectrum.svg/660px-EM_spectrum.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f1/EM_spectrum.svg/880px-EM_spectrum.svg.png 2x" data-file-width="788" data-file-height="374" /></a><figcaption>Complete spectrum of <a href="/wiki/Electromagnetic_radiation" title="Electromagnetic radiation">electromagnetic radiation</a> with the visible portion highlighted</figcaption></figure> <p>Visible light is an <a href="/wiki/Electromagnetic_wave" class="mw-redirect" title="Electromagnetic wave">electromagnetic wave</a>, consisting of oscillating <a href="/wiki/Electric_field" title="Electric field">electric</a> and <a href="/wiki/Magnetic_field" title="Magnetic field">magnetic fields</a> traveling through space. The frequency of the wave determines its color: 400 THz (<span class="nowrap"><span data-sort-value="7014400000000000000♠"></span>4<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>14</sup></span> Hz) is red light, 800 THz (<span class="nowrap"><span data-sort-value="7014800000000000000♠"></span>8<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>14</sup> Hz</span>) is violet light, and between these (in the range 400–800 THz) are all the other colors of the <a href="/wiki/Visible_spectrum" title="Visible spectrum">visible spectrum</a>. An electromagnetic wave with a frequency less than <span class="nowrap"><span data-sort-value="7014400000000000000♠"></span>4<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>14</sup> Hz</span> will be invisible to the human eye; such waves are called <a href="/wiki/Infrared" title="Infrared">infrared</a> (IR) radiation. At even lower frequency, the wave is called a <a href="/wiki/Microwave" title="Microwave">microwave</a>, and at still lower frequencies it is called a <a href="/wiki/Radio_wave" title="Radio wave">radio wave</a>. Likewise, an electromagnetic wave with a frequency higher than <span class="nowrap"><span data-sort-value="7014800000000000000♠"></span>8<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>14</sup> Hz</span> will also be invisible to the human eye; such waves are called <a href="/wiki/Ultraviolet" title="Ultraviolet">ultraviolet</a> (UV) radiation. Even higher-frequency waves are called <a href="/wiki/X-ray" title="X-ray">X-rays</a>, and higher still are <a href="/wiki/Gamma_ray" title="Gamma ray">gamma rays</a>. </p><p>All of these waves, from the lowest-frequency radio waves to the highest-frequency gamma rays, are fundamentally the same, and they are all called <a href="/wiki/Electromagnetic_radiation" title="Electromagnetic radiation">electromagnetic radiation</a>. They all travel through vacuum at the same speed (the speed of light), giving them wavelengths inversely proportional to their frequencies. <span class="mwe-math-element" data-qid="Q2111"><a href="/w/index.php?title=Special:MathWikibase&qid=Q2111" style="color:inherit;"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \displaystyle c=f\lambda ,}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mstyle displaystyle="true" scriptlevel="0"> <mi>c</mi> <mo>=</mo> <mi>f</mi> <mi>λ</mi> <mo>,</mo> </mstyle> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \displaystyle c=f\lambda ,}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/3d59bfb44bbd4c234fabaa8337fa47f7579e2f94" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:7.386ex; height:2.509ex;" alt="{\displaystyle \displaystyle c=f\lambda ,}"></a></span> where <i>c</i> is the speed of light (<i>c</i> in vacuum or less in other media), <i>f</i> is the frequency and <i>λ</i> is the wavelength. </p><p>In <a href="/wiki/Dispersion_(optics)" title="Dispersion (optics)">dispersive media</a>, such as glass, the speed depends somewhat on frequency, so the wavelength is not quite inversely proportional to frequency. </p> <div class="mw-heading mw-heading3"><h3 id="Sound">Sound</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=12" title="Edit section: Sound"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Audio_frequency" title="Audio frequency">Audio frequency</a></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Ultrasound_range_diagram.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/7/74/Ultrasound_range_diagram.svg/370px-Ultrasound_range_diagram.svg.png" decoding="async" width="370" height="88" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/74/Ultrasound_range_diagram.svg/555px-Ultrasound_range_diagram.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/74/Ultrasound_range_diagram.svg/740px-Ultrasound_range_diagram.svg.png 2x" data-file-width="481" data-file-height="114" /></a><figcaption>The <a href="/wiki/Sound_wave" class="mw-redirect" title="Sound wave">sound wave</a> spectrum, with rough guide of some applications</figcaption></figure> <p>Sound propagates as mechanical vibration waves of pressure and displacement, in air or other substances.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> In general, frequency components of a sound determine its "color", its <a href="/wiki/Timbre" title="Timbre">timbre</a>. When speaking about the frequency (in singular) of a sound, it means the property that most determines its <a href="/wiki/Pitch_(music)" title="Pitch (music)">pitch</a>.<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> </p><p>The frequencies an ear can hear are limited to a <a href="/wiki/Threshold_of_hearing" class="mw-redirect" title="Threshold of hearing">specific range of frequencies</a>. The <a href="/wiki/Audible_frequency" class="mw-redirect" title="Audible frequency">audible frequency</a> range for humans is typically given as being between about 20 Hz and 20,000 Hz (20 kHz), though the high frequency limit usually reduces with age. Other <a href="/wiki/Species" title="Species">species</a> have different hearing ranges. For example, some dog breeds can perceive vibrations up to 60,000 Hz.<sup id="cite_ref-Physics_Factbook_13-0" class="reference"><a href="#cite_note-Physics_Factbook-13"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> </p><p>In many media, such as air, the <a href="/wiki/Speed_of_sound" title="Speed of sound">speed of sound</a> is approximately independent of frequency, so the wavelength of the sound waves (distance between repetitions) is approximately inversely proportional to frequency. </p> <div class="mw-heading mw-heading3"><h3 id="Line_current">Line current</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=13" title="Edit section: Line current"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Utility_frequency" title="Utility frequency">Utility frequency</a></div> <p>In <a href="/wiki/Europe" title="Europe">Europe</a>, <a href="/wiki/Africa" title="Africa">Africa</a>, <a href="/wiki/Australia" title="Australia">Australia</a>, southern <a href="/wiki/South_America" title="South America">South America</a>, most of <a href="/wiki/Asia" title="Asia">Asia</a>, and <a href="/wiki/Russia" title="Russia">Russia</a>, the frequency of the <a href="/wiki/Alternating_current" title="Alternating current">alternating current</a> in <a href="/wiki/Mains_electricity" title="Mains electricity">household electrical outlets</a> is 50 Hz (close to the <a href="/wiki/Musical_note" title="Musical note">tone</a> G), whereas in <a href="/wiki/North_America" title="North America">North America</a> and northern South America, the frequency of the alternating current in household electrical outlets is 60 Hz (between the tones B<span class="music-symbol" style="font-family: Arial Unicode MS, Lucida Sans Unicode;"><span class="music-flat">♭</span></span> and B; that is, a <a href="/wiki/Minor_third" title="Minor third">minor third</a> above the European frequency). The frequency of the '<a href="/wiki/Mains_hum" title="Mains hum">hum</a>' in an <a href="/wiki/Audio_recording" class="mw-redirect" title="Audio recording">audio recording</a> can show in which of these general regions the recording was made. </p> <div class="mw-heading mw-heading2"><h2 id="Aperiodic_frequency">Aperiodic frequency</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=14" title="Edit section: Aperiodic frequency"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><b>Aperiodic frequency</b> is the <a href="/wiki/Rate_(mathematics)" title="Rate (mathematics)">rate</a> of incidence or occurrence of non-<a href="/wiki/Periodic_function" title="Periodic function">cyclic</a> phenomena, including random processes such as <a href="/wiki/Radioactive_decay" title="Radioactive decay">radioactive decay</a>. It is expressed with the unit <a href="/wiki/Reciprocal_second" class="mw-redirect" title="Reciprocal second">reciprocal second</a> (s<sup>−1</sup>)<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> or, in the case of radioactivity, with the unit <a href="/wiki/Becquerel" title="Becquerel">becquerel</a>.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> </p><p>It is defined as a <a href="/wiki/Rate_(mathematics)" title="Rate (mathematics)">rate</a>, <span class="nowrap"><i>f</i> = <i>N</i>/Δ<i>t</i></span>, involving the <a href="/wiki/Number_of_entities" class="mw-redirect" title="Number of entities">number of entities</a> counted or the number of <a href="/wiki/Event_(philosophy)" title="Event (philosophy)">events</a> happened (<i>N</i>) during a given <a href="/wiki/Time" title="Time">time duration</a> (Δ<i>t</i>);<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (July 2023)">citation needed</span></a></i>]</sup> it is a <a href="/wiki/Physical_quantity" title="Physical quantity">physical quantity</a> of type <a href="/wiki/Temporal_rate" class="mw-redirect" title="Temporal rate">temporal rate</a>. </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=15" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/Frequency_(disambiguation)" class="mw-disambig" title="Frequency (disambiguation)">Frequency (disambiguation)</a> and <a href="/wiki/Category:Units_of_frequency" title="Category:Units of frequency">Category:Units of frequency</a></div> <style data-mw-deduplicate="TemplateStyles:r1184024115">.mw-parser-output .div-col{margin-top:0.3em;column-width:30em}.mw-parser-output .div-col-small{font-size:90%}.mw-parser-output .div-col-rules{column-rule:1px solid #aaa}.mw-parser-output .div-col dl,.mw-parser-output .div-col ol,.mw-parser-output .div-col ul{margin-top:0}.mw-parser-output .div-col li,.mw-parser-output .div-col dd{page-break-inside:avoid;break-inside:avoid-column}</style><div class="div-col" style="column-width: 20em;"> <ul><li><a href="/wiki/Audio_frequency" title="Audio frequency">Audio frequency</a></li> <li><a href="/wiki/Bandwidth_(signal_processing)" title="Bandwidth (signal processing)">Bandwidth (signal processing)</a></li> <li><a href="/wiki/Chirp" title="Chirp">Chirp</a></li> <li><a href="/wiki/Cutoff_frequency" title="Cutoff frequency">Cutoff frequency</a></li> <li><a href="/wiki/Downsampling" class="mw-redirect" title="Downsampling">Downsampling</a></li> <li><a href="/wiki/Electronic_filter" title="Electronic filter">Electronic filter</a></li> <li><a href="/wiki/Fourier_analysis" title="Fourier analysis">Fourier analysis</a></li> <li><a href="/wiki/Frequency_band" class="mw-redirect" title="Frequency band">Frequency band</a></li> <li><a href="/wiki/Frequency_converter" class="mw-redirect" title="Frequency converter">Frequency converter</a></li> <li><a href="/wiki/Frequency_domain" title="Frequency domain">Frequency domain</a></li> <li><a href="/wiki/Frequency_distribution" class="mw-redirect" title="Frequency distribution">Frequency distribution</a></li> <li><a href="/wiki/Frequency_extender" title="Frequency extender">Frequency extender</a></li> <li><a href="/wiki/Frequency_grid" title="Frequency grid">Frequency grid</a></li> <li><a href="/wiki/Frequency_level" class="mw-redirect" title="Frequency level">Frequency level</a></li> <li><a href="/wiki/Frequency_modulation" title="Frequency modulation">Frequency modulation</a></li> <li><a href="/wiki/Frequency_spectrum" class="mw-redirect" title="Frequency spectrum">Frequency spectrum</a></li> <li><a href="/wiki/Interaction_frequency" title="Interaction frequency">Interaction frequency</a></li> <li><a href="/wiki/Least-squares_spectral_analysis" title="Least-squares spectral analysis">Least-squares spectral analysis</a></li> <li><a href="/wiki/Natural_frequency" title="Natural frequency">Natural frequency</a></li> <li><a href="/wiki/Negative_frequency" title="Negative frequency">Negative frequency</a></li> <li><a href="/wiki/Periodicity_(disambiguation)" class="mw-redirect mw-disambig" title="Periodicity (disambiguation)">Periodicity (disambiguation)</a></li> <li><a href="/wiki/Pink_noise" title="Pink noise">Pink noise</a></li> <li><a href="/wiki/Preselector" title="Preselector">Preselector</a></li> <li><a href="/wiki/Radar_signal_characteristics" title="Radar signal characteristics">Radar signal characteristics</a></li> <li><a href="/wiki/Radio_frequency" title="Radio frequency">Radio frequency</a></li> <li><a href="/wiki/Signaling_(telecommunications)" title="Signaling (telecommunications)">Signaling (telecommunications)</a></li> <li><a href="/wiki/Spread_spectrum" title="Spread spectrum">Spread spectrum</a></li> <li><a href="/wiki/Spectral_component" class="mw-redirect" title="Spectral component">Spectral component</a></li> <li><a href="/wiki/Transverter" title="Transverter">Transverter</a></li> <li><a href="/wiki/Upsampling" title="Upsampling">Upsampling</a></li> <li><a href="/wiki/Orders_of_magnitude_(frequency)" title="Orders of magnitude (frequency)">Orders of magnitude (frequency)</a></li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="Notes">Notes</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=16" title="Edit section: Notes"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text">The term <i>spatial period</i>, sometimes used in place of <i><a href="/wiki/Wavelength" title="Wavelength">wavelength</a></i>, analogously corresponds to the (temporal) period.<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=17" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239543626"><div class="reflist reflist-columns references-column-width"> <ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.merriam-webster.com/dictionary/frequency">"Definition of FREQUENCY"</a><span class="reference-accessdate">. Retrieved <span class="nowrap">3 October</span> 2016</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Definition+of+FREQUENCY&rft_id=http%3A%2F%2Fwww.merriam-webster.com%2Fdictionary%2Ffrequency&rfr_id=info%3Asid%2Fen.wikipedia.org%3AFrequency" class="Z3988"></span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.merriam-webster.com/dictionary/period">"Definition of PERIOD"</a><span class="reference-accessdate">. Retrieved <span class="nowrap">3 October</span> 2016</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Definition+of+PERIOD&rft_id=http%3A%2F%2Fwww.merriam-webster.com%2Fdictionary%2Fperiod&rfr_id=info%3Asid%2Fen.wikipedia.org%3AFrequency" class="Z3988"></span></span> </li> <li id="cite_note-FOOTNOTESerwayFaughn1989346-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTESerwayFaughn1989346_3-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFSerwayFaughn1989">Serway & Faughn 1989</a>, p. 346.</span> </li> <li id="cite_note-FOOTNOTESerwayFaughn1989354-4"><span class="mw-cite-backlink">^ <a href="#cite_ref-FOOTNOTESerwayFaughn1989354_4-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-FOOTNOTESerwayFaughn1989354_4-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><a href="#CITEREFSerwayFaughn1989">Serway & Faughn 1989</a>, p. 354.</span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20200408155740/https://www.bipm.org/en/CGPM/db/11/12/">"Resolution 12 of the 11th CGPM (1960)"</a>. BIPM (International Bureau of Weights and Measures). Archived from <a rel="nofollow" class="external text" href="https://www.bipm.org/en/CGPM/db/11/12/">the original</a> on 8 April 2020<span class="reference-accessdate">. Retrieved <span class="nowrap">21 January</span> 2021</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Resolution+12+of+the+11th+CGPM+%281960%29&rft.pub=BIPM+%28International+Bureau+of+Weights+and+Measures%29&rft_id=https%3A%2F%2Fwww.bipm.org%2Fen%2FCGPM%2Fdb%2F11%2F12%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AFrequency" class="Z3988"></span></span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation journal cs1"><a rel="nofollow" class="external text" href="https://www.nist.gov/pml/special-publication-811/nist-guide-si-chapter-8">"Special Publication 811: NIST Guide to the SI, Chapter 8"</a>. <i>NIST</i>. 28 January 2016<span class="reference-accessdate">. Retrieved <span class="nowrap">2022-11-08</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=NIST&rft.atitle=Special+Publication+811%3A+NIST+Guide+to+the+SI%2C+Chapter+8&rft.date=2016-01-28&rft_id=https%3A%2F%2Fwww.nist.gov%2Fpml%2Fspecial-publication-811%2Fnist-guide-si-chapter-8&rfr_id=info%3Asid%2Fen.wikipedia.org%3AFrequency" class="Z3988"></span></span> </li> <li id="cite_note-FOOTNOTEDavies1997275-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEDavies1997275_7-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFDavies1997">Davies 1997</a>, p. 275.</span> </li> <li id="cite_note-FOOTNOTEYoung19997-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEYoung19997_8-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFYoung1999">Young 1999</a>, p. 7.</span> </li> <li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBoreman" class="citation web cs1">Boreman, Glenn D. <a rel="nofollow" class="external text" href="https://spie.org/publications/tt52_12_spatial_frequency?SSO=1">"Spatial Frequency"</a>. <a href="/wiki/SPIE" title="SPIE">SPIE</a><span class="reference-accessdate">. Retrieved <span class="nowrap">22 January</span> 2021</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Spatial+Frequency&rft.pub=SPIE&rft.aulast=Boreman&rft.aufirst=Glenn+D.&rft_id=https%3A%2F%2Fspie.org%2Fpublications%2Ftt52_12_spatial_frequency%3FSSO%3D1&rfr_id=info%3Asid%2Fen.wikipedia.org%3AFrequency" class="Z3988"></span></span> </li> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.merriam-webster.com/dictionary/sound">"Definition of SOUND"</a><span class="reference-accessdate">. Retrieved <span class="nowrap">3 October</span> 2016</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Definition+of+SOUND&rft_id=http%3A%2F%2Fwww.merriam-webster.com%2Fdictionary%2Fsound&rfr_id=info%3Asid%2Fen.wikipedia.org%3AFrequency" class="Z3988"></span></span> </li> <li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPilhofer2007" class="citation book cs1">Pilhofer, Michael (2007). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=CxcviUw4KX8C"><i>Music Theory for Dummies</i></a>. For Dummies. p. 97. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-470-16794-6" title="Special:BookSources/978-0-470-16794-6"><bdi>978-0-470-16794-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Music+Theory+for+Dummies&rft.pages=97&rft.pub=For+Dummies&rft.date=2007&rft.isbn=978-0-470-16794-6&rft.aulast=Pilhofer&rft.aufirst=Michael&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DCxcviUw4KX8C&rfr_id=info%3Asid%2Fen.wikipedia.org%3AFrequency" class="Z3988"></span></span> </li> <li id="cite_note-Physics_Factbook-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-Physics_Factbook_13-0">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCondon2003" class="citation web cs1">Condon, Tim (2003). Elert, Glenn (ed.). <a rel="nofollow" class="external text" href="https://hypertextbook.com/facts/2003/TimCondon.shtml">"Frequency range of dog hearing"</a>. <i>The Physics Factbook</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2008-10-22</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=The+Physics+Factbook&rft.atitle=Frequency+range+of+dog+hearing&rft.date=2003&rft.aulast=Condon&rft.aufirst=Tim&rft_id=https%3A%2F%2Fhypertextbook.com%2Ffacts%2F2003%2FTimCondon.shtml&rfr_id=info%3Asid%2Fen.wikipedia.org%3AFrequency" class="Z3988"></span></span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLombardi2007" class="citation book cs1">Lombardi, Michael A. (2007). "Fundamentals of Time and Frequency". In Bishop, Robert H. (ed.). <i>Mechatronic Systems, Sensors, and Actuators: Fundamentals and Modeling</i>. Austin: CRC Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9781420009002" title="Special:BookSources/9781420009002"><bdi>9781420009002</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Fundamentals+of+Time+and+Frequency&rft.btitle=Mechatronic+Systems%2C+Sensors%2C+and+Actuators%3A+Fundamentals+and+Modeling&rft.place=Austin&rft.pub=CRC+Press&rft.date=2007&rft.isbn=9781420009002&rft.aulast=Lombardi&rft.aufirst=Michael+A.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AFrequency" class="Z3988"></span></span> </li> <li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNewellTiesinga2019" class="citation report cs1">Newell, David B; Tiesinga, Eite (2019). <a rel="nofollow" class="external text" href="https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.330-2019.pdf">The international system of units (SI)</a> <span class="cs1-format">(PDF)</span> (Report). Gaithersburg, MD: National Institute of Standards and Technology. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.6028%2Fnist.sp.330-2019">10.6028/nist.sp.330-2019</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=report&rft.btitle=The+international+system+of+units+%28SI%29&rft.place=Gaithersburg%2C+MD&rft.pub=National+Institute+of+Standards+and+Technology&rft.date=2019&rft_id=info%3Adoi%2F10.6028%2Fnist.sp.330-2019&rft.aulast=Newell&rft.aufirst=David+B&rft.au=Tiesinga%2C+Eite&rft_id=https%3A%2F%2Fnvlpubs.nist.gov%2Fnistpubs%2FSpecialPublications%2FNIST.SP.330-2019.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AFrequency" class="Z3988"></span> sub§2.3.4, Table 4.</span> </li> </ol></div> <div class="mw-heading mw-heading2"><h2 id="Sources">Sources</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=18" title="Edit section: Sources"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDavies1997" class="citation book cs1">Davies, A. (1997). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=j2mN2aIs2YIC&pg=RA1-PA275"><i>Handbook of Condition Monitoring: Techniques and Methodology</i></a>. New York: Springer. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-412-61320-3" title="Special:BookSources/978-0-412-61320-3"><bdi>978-0-412-61320-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Handbook+of+Condition+Monitoring%3A+Techniques+and+Methodology&rft.place=New+York&rft.pub=Springer&rft.date=1997&rft.isbn=978-0-412-61320-3&rft.aulast=Davies&rft.aufirst=A.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3Dj2mN2aIs2YIC%26pg%3DRA1-PA275&rfr_id=info%3Asid%2Fen.wikipedia.org%3AFrequency" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSerwayFaughn1989" class="citation book cs1">Serway, Raymond A.; Faughn, Jerry S. (1989). <span class="id-lock-registration" title="Free registration required"><a rel="nofollow" class="external text" href="https://archive.org/details/collegephysics00serw/mode/2up?q=frequency"><i>College Physics</i></a></span>. London: Thomson/Brooks-Cole. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-05344-0-814-5" title="Special:BookSources/978-05344-0-814-5"><bdi>978-05344-0-814-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=College+Physics&rft.place=London&rft.pub=Thomson%2FBrooks-Cole&rft.date=1989&rft.isbn=978-05344-0-814-5&rft.aulast=Serway&rft.aufirst=Raymond+A.&rft.au=Faughn%2C+Jerry+S.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fcollegephysics00serw%2Fmode%2F2up%3Fq%3Dfrequency&rfr_id=info%3Asid%2Fen.wikipedia.org%3AFrequency" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFYoung1999" class="citation book cs1">Young, Ian R. (1999). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=ph7GKZZGjyYC&q=ocean+waves"><i>Wind Generated Ocean Waves</i></a>. Elsevere Ocean Engineering. Vol. 2. Oxford: Elsevier. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-08-043317-2" title="Special:BookSources/978-0-08-043317-2"><bdi>978-0-08-043317-2</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Wind+Generated+Ocean+Waves&rft.place=Oxford&rft.series=Elsevere+Ocean+Engineering&rft.pub=Elsevier&rft.date=1999&rft.isbn=978-0-08-043317-2&rft.aulast=Young&rft.aufirst=Ian+R.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3Dph7GKZZGjyYC%26q%3Docean%2Bwaves&rfr_id=info%3Asid%2Fen.wikipedia.org%3AFrequency" class="Z3988"></span></li></ul> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=19" title="Edit section: Further reading"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation book cs1">Giancoli, D.C. (1988). <i>Physics for Scientists and Engineers</i> (2nd ed.). Prentice Hall. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-13-669201-0" title="Special:BookSources/978-0-13-669201-0"><bdi>978-0-13-669201-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Physics+for+Scientists+and+Engineers&rft.edition=2nd&rft.pub=Prentice+Hall&rft.date=1988&rft.isbn=978-0-13-669201-0&rft.aulast=Giancoli&rft.aufirst=D.C.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AFrequency" class="Z3988"></span></li></ul> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Frequency&action=edit&section=20" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1;min-width:0}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}</style><style data-mw-deduplicate="TemplateStyles:r1237033735">@media print{body.ns-0 .mw-parser-output .sistersitebox{display:none!important}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}</style><div class="side-box side-box-right plainlinks sistersitebox"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"> <div class="side-box-flex"> <div class="side-box-image"><span class="noviewer" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/9/99/Wiktionary-logo-en-v2.svg/40px-Wiktionary-logo-en-v2.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/99/Wiktionary-logo-en-v2.svg/60px-Wiktionary-logo-en-v2.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/99/Wiktionary-logo-en-v2.svg/80px-Wiktionary-logo-en-v2.svg.png 2x" data-file-width="512" data-file-height="512" /></span></span></div> <div class="side-box-text plainlist">Look up <i><b><a href="https://en.wiktionary.org/wiki/frequency" class="extiw" title="wiktionary:frequency">frequency</a></b></i> or <i><b><a href="https://en.wiktionary.org/wiki/often" class="extiw" title="wiktionary:often">often</a></b></i> in Wiktionary, the free dictionary.</div></div> </div> <ul><li><a rel="nofollow" class="external text" href="http://www.sengpielaudio.com/calculator-notenames.htm">Keyboard frequencies = naming of notes – The English and American system versus the German system</a></li> <li><a rel="nofollow" class="external text" href="http://onlinetonegenerator.com">A frequency generator with sound, useful for hearing tests</a></li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist li::after{content:" · ";font-weight:bold}.mw-parser-output .hlist dd:last-child::after,.mw-parser-output .hlist dt:last-child::after,.mw-parser-output .hlist li:last-child::after{content:none}.mw-parser-output .hlist dd dd:first-child::before,.mw-parser-output .hlist dd dt:first-child::before,.mw-parser-output .hlist dd li:first-child::before,.mw-parser-output .hlist dt dd:first-child::before,.mw-parser-output .hlist dt dt:first-child::before,.mw-parser-output .hlist dt li:first-child::before,.mw-parser-output .hlist li dd:first-child::before,.mw-parser-output .hlist li dt:first-child::before,.mw-parser-output .hlist li li:first-child::before{content:" (";font-weight:normal}.mw-parser-output .hlist dd dd:last-child::after,.mw-parser-output .hlist dd dt:last-child::after,.mw-parser-output .hlist dd li:last-child::after,.mw-parser-output .hlist dt dd:last-child::after,.mw-parser-output .hlist dt dt:last-child::after,.mw-parser-output .hlist dt li:last-child::after,.mw-parser-output .hlist li dd:last-child::after,.mw-parser-output .hlist li dt:last-child::after,.mw-parser-output .hlist li li:last-child::after{content:")";font-weight:normal}.mw-parser-output .hlist ol{counter-reset:listitem}.mw-parser-output .hlist ol>li{counter-increment:listitem}.mw-parser-output .hlist ol>li::before{content:" "counter(listitem)"\a0 "}.mw-parser-output .hlist dd ol>li:first-child::before,.mw-parser-output .hlist dt ol>li:first-child::before,.mw-parser-output .hlist li ol>li:first-child::before{content:" ("counter(listitem)"\a0 "}</style><style data-mw-deduplicate="TemplateStyles:r1236075235">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"></div><div role="navigation" class="navbox" aria-labelledby="Acoustics" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="3"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Acoustics" title="Template:Acoustics"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Acoustics" title="Template talk:Acoustics"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Acoustics" title="Special:EditPage/Template:Acoustics"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Acoustics" style="font-size:114%;margin:0 4em"><a href="/wiki/Acoustics" title="Acoustics">Acoustics</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Acoustical_engineering" title="Acoustical engineering">Acoustical engineering</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Architectural_acoustics" title="Architectural acoustics">Architectural acoustics</a></li> <li><a href="/wiki/Monochord" title="Monochord">Monochord</a></li> <li><a href="/wiki/Reverberation" title="Reverberation">Reverberation</a></li> <li><a href="/wiki/Soundproofing" title="Soundproofing">Soundproofing</a></li> <li><a href="/wiki/String_vibration" title="String vibration">String vibration</a></li> <li><a href="/wiki/Sympathetic_resonance" title="Sympathetic resonance">Sympathetic resonance</a></li></ul> </div></td><td class="noviewer navbox-image" rowspan="5" style="width:1px;padding:0 0 0 2px"><div><div class="plainlist"><ul><li><span typeof="mw:File"><a href="/wiki/File:Spectrogram_showing_shared_partials.png" class="mw-file-description"><img alt="A spectrogram of a violin playing a note and then a perfect fifth above it. The shared partials are highlighted by the white dashes." src="//upload.wikimedia.org/wikipedia/commons/thumb/2/26/Spectrogram_showing_shared_partials.png/80px-Spectrogram_showing_shared_partials.png" decoding="async" width="80" height="67" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/26/Spectrogram_showing_shared_partials.png/120px-Spectrogram_showing_shared_partials.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/26/Spectrogram_showing_shared_partials.png/160px-Spectrogram_showing_shared_partials.png 2x" data-file-width="300" data-file-height="250" /></a></span></li><li><span style="font-size:85%;"><a href="/wiki/Spectrogram" title="Spectrogram">Spectrogram</a></span></li></ul></div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Psychoacoustics" title="Psychoacoustics">Psychoacoustics</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Pitch_(music)" title="Pitch (music)">Pitch</a> <ul><li><a href="/wiki/Bark_scale" title="Bark scale">Bark scale</a></li> <li><a href="/wiki/Mel_scale" title="Mel scale">Mel scale</a></li></ul></li> <li><a href="/wiki/Equal-loudness_contour" title="Equal-loudness contour">Equal-loudness contour</a> <ul><li><a href="/wiki/Fletcher%E2%80%93Munson_curves" class="mw-redirect" title="Fletcher–Munson curves">Fletcher–Munson curves</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Audio_frequency" title="Audio frequency">Audio frequency</a> and <a href="/wiki/Pitch_(music)" title="Pitch (music)">pitch</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Beat_(acoustics)" title="Beat (acoustics)">Beat</a></li> <li><a href="/wiki/Formant" title="Formant">Formant</a></li> <li><a href="/wiki/Fundamental_frequency" title="Fundamental frequency">Fundamental frequency</a></li> <li><a href="/wiki/Frequency_spectrum" class="mw-redirect" title="Frequency spectrum">Frequency spectrum</a> <ul><li><a href="/wiki/Harmonic_spectrum" title="Harmonic spectrum">harmonic spectrum</a></li></ul></li> <li><a href="/wiki/Harmonic" title="Harmonic">Harmonic</a> <ul><li><a href="/wiki/Harmonic_series_(music)" title="Harmonic series (music)">Series</a></li> <li><a href="/wiki/Inharmonicity" title="Inharmonicity">Inharmonicity</a></li> <li><a href="/wiki/Missing_fundamental" title="Missing fundamental">Missing fundamental</a></li></ul></li> <li><a href="/wiki/Combination_tone" title="Combination tone">Combination tone</a></li> <li><a href="/wiki/Mersenne%27s_laws" title="Mersenne's laws">Mersenne's laws</a></li> <li><a href="/wiki/Overtone" title="Overtone">Overtone</a></li> <li><a href="/wiki/Acoustic_resonance" title="Acoustic resonance">Resonance</a></li> <li><a href="/wiki/Standing_wave" title="Standing wave">Standing wave</a> <ul><li><a href="/wiki/Node_(physics)" title="Node (physics)">Node</a></li></ul></li> <li><a href="/wiki/Undertone_series" title="Undertone series">Subharmonic</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Acousticians</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/John_Backus_(acoustician)" title="John Backus (acoustician)">John Backus</a></li> <li><a href="/wiki/Jens_Blauert" title="Jens Blauert">Jens Blauert</a></li> <li><a href="/wiki/Ernst_Chladni" title="Ernst Chladni">Ernst Chladni</a></li> <li><a href="/wiki/Hermann_von_Helmholtz" title="Hermann von Helmholtz">Hermann von Helmholtz</a></li> <li><a href="/wiki/Carleen_Hutchins" title="Carleen Hutchins">Carleen Hutchins</a></li> <li><a href="/wiki/Franz_Melde" title="Franz Melde">Franz Melde</a></li> <li><a href="/wiki/Marin_Mersenne" title="Marin Mersenne">Marin Mersenne</a></li> <li><a href="/wiki/Werner_Meyer-Eppler" title="Werner Meyer-Eppler">Werner Meyer-Eppler</a></li> <li><a href="/wiki/John_William_Strutt,_3rd_Baron_Rayleigh" title="John William Strutt, 3rd Baron Rayleigh">Lord Rayleigh</a></li> <li><a href="/wiki/Joseph_Sauveur" title="Joseph Sauveur">Joseph Sauveur</a></li> <li><a href="/wiki/D._Van_Holliday" title="D. Van Holliday">D. Van Holliday</a></li> <li><a href="/wiki/Thomas_Young_(scientist)" title="Thomas Young (scientist)">Thomas Young</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Related topics</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Echo" title="Echo">Echo</a></li> <li><a href="/wiki/Infrasound" title="Infrasound">Infrasound</a></li> <li><a href="/wiki/Sound" title="Sound">Sound</a></li> <li><a href="/wiki/Ultrasound" title="Ultrasound">Ultrasound</a></li> <li><a href="/wiki/Musical_acoustics" title="Musical acoustics">Musical acoustics</a> <ul><li><a href="/wiki/Piano_acoustics" title="Piano acoustics">Piano</a></li> <li><a href="/wiki/Violin_acoustics" title="Violin acoustics">Violin</a></li></ul></li></ul> </div></td></tr><tr><td class="navbox-abovebelow hlist" colspan="3"><div> <ul><li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:Acoustics" title="Category:Acoustics">Category</a></li></ul> </div></td></tr></tbody></table></div> <style data-mw-deduplicate="TemplateStyles:r1130092004">.mw-parser-output .portal-bar{font-size:88%;font-weight:bold;display:flex;justify-content:center;align-items:baseline}.mw-parser-output .portal-bar-bordered{padding:0 2em;background-color:#fdfdfd;border:1px solid #a2a9b1;clear:both;margin:1em auto 0}.mw-parser-output .portal-bar-related{font-size:100%;justify-content:flex-start}.mw-parser-output .portal-bar-unbordered{padding:0 1.7em;margin-left:0}.mw-parser-output .portal-bar-header{margin:0 1em 0 0.5em;flex:0 0 auto;min-height:24px}.mw-parser-output .portal-bar-content{display:flex;flex-flow:row wrap;flex:0 1 auto;padding:0.15em 0;column-gap:1em;align-items:baseline;margin:0;list-style:none}.mw-parser-output .portal-bar-content-related{margin:0;list-style:none}.mw-parser-output .portal-bar-item{display:inline-block;margin:0.15em 0.2em;min-height:24px;line-height:24px}@media screen and (max-width:768px){.mw-parser-output .portal-bar{font-size:88%;font-weight:bold;display:flex;flex-flow:column wrap;align-items:baseline}.mw-parser-output .portal-bar-header{text-align:center;flex:0;padding-left:0.5em;margin:0 auto}.mw-parser-output .portal-bar-related{font-size:100%;align-items:flex-start}.mw-parser-output .portal-bar-content{display:flex;flex-flow:row wrap;align-items:center;flex:0;column-gap:1em;border-top:1px solid #a2a9b1;margin:0 auto;list-style:none}.mw-parser-output .portal-bar-content-related{border-top:none;margin:0;list-style:none}}.mw-parser-output .navbox+link+.portal-bar,.mw-parser-output .navbox+style+.portal-bar,.mw-parser-output .navbox+link+.portal-bar-bordered,.mw-parser-output .navbox+style+.portal-bar-bordered,.mw-parser-output .sister-bar+link+.portal-bar,.mw-parser-output .sister-bar+style+.portal-bar,.mw-parser-output .portal-bar+.navbox-styles+.navbox,.mw-parser-output .portal-bar+.navbox-styles+.sister-bar{margin-top:-1px}</style><div class="portal-bar noprint metadata noviewer portal-bar-bordered" role="navigation" aria-label="Portals"><span class="portal-bar-header"><a href="/wiki/Wikipedia:Contents/Portals" title="Wikipedia:Contents/Portals">Portal</a>:</span><ul class="portal-bar-content"><li class="portal-bar-item"><span class="nowrap"><span typeof="mw:File"><a href="/wiki/File:Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg" class="mw-file-description"><img alt="icon" src="//upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/17px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png" decoding="async" width="17" height="19" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/26px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/34px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png 2x" data-file-width="530" data-file-height="600" /></a></span> </span><a href="/wiki/Portal:Physics" title="Portal:Physics">Physics</a></li></ul></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox authority-control" aria-label="Navbox" style="padding:3px"><table class="nowraplinks hlist navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Help:Authority_control" title="Help:Authority control">Authority control databases</a>: National <span class="mw-valign-text-top noprint" typeof="mw:File/Frameless"><a href="https://www.wikidata.org/wiki/Q11652#identifiers" title="Edit this at Wikidata"><img alt="Edit this at Wikidata" src="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/10px-OOjs_UI_icon_edit-ltr-progressive.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/15px-OOjs_UI_icon_edit-ltr-progressive.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/20px-OOjs_UI_icon_edit-ltr-progressive.svg.png 2x" data-file-width="20" data-file-height="20" /></a></span></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"><ul><li><span class="uid"><a rel="nofollow" class="external text" href="https://d-nb.info/gnd/4121292-7">Germany</a></span></li></ul></div></td></tr></tbody></table></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Frequency&oldid=1258830676">https://en.wikipedia.org/w/index.php?title=Frequency&oldid=1258830676</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Category</a>: <ul><li><a href="/wiki/Category:Frequency" title="Category:Frequency">Frequency</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden categories: <ul><li><a href="/wiki/Category:Articles_with_short_description" title="Category:Articles with short description">Articles with short description</a></li><li><a href="/wiki/Category:Short_description_is_different_from_Wikidata" title="Category:Short description is different from Wikidata">Short description is different from Wikidata</a></li><li><a href="/wiki/Category:All_articles_with_unsourced_statements" title="Category:All articles with unsourced statements">All articles with unsourced statements</a></li><li><a href="/wiki/Category:Articles_with_unsourced_statements_from_April_2024" title="Category:Articles with unsourced statements from April 2024">Articles with unsourced statements from April 2024</a></li><li><a href="/wiki/Category:Articles_with_unsourced_statements_from_July_2023" title="Category:Articles with unsourced statements from July 2023">Articles with unsourced statements from July 2023</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> This page was last edited on 21 November 2024, at 21:39<span class="anonymous-show"> (UTC)</span>.</li> <li id="footer-info-copyright">Text is available under the <a href="/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License" title="Wikipedia:Text of the Creative Commons Attribution-ShareAlike 4.0 International License">Creative Commons Attribution-ShareAlike 4.0 License</a>; additional terms may apply. By using this site, you agree to the <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use" class="extiw" title="foundation:Special:MyLanguage/Policy:Terms of Use">Terms of Use</a> and <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy" class="extiw" title="foundation:Special:MyLanguage/Policy:Privacy policy">Privacy Policy</a>. Wikipedia® is a registered trademark of the <a rel="nofollow" class="external text" href="https://wikimediafoundation.org/">Wikimedia Foundation, Inc.</a>, a non-profit organization.</li> </ul> <ul id="footer-places"> <li id="footer-places-privacy"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy">Privacy policy</a></li> <li id="footer-places-about"><a href="/wiki/Wikipedia:About">About Wikipedia</a></li> <li id="footer-places-disclaimers"><a href="/wiki/Wikipedia:General_disclaimer">Disclaimers</a></li> <li id="footer-places-contact"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us">Contact Wikipedia</a></li> <li id="footer-places-wm-codeofconduct"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct">Code of Conduct</a></li> <li id="footer-places-developers"><a href="https://developer.wikimedia.org">Developers</a></li> <li id="footer-places-statslink"><a href="https://stats.wikimedia.org/#/en.wikipedia.org">Statistics</a></li> <li id="footer-places-cookiestatement"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement">Cookie statement</a></li> <li id="footer-places-mobileview"><a href="//en.m.wikipedia.org/w/index.php?title=Frequency&mobileaction=toggle_view_mobile" class="noprint stopMobileRedirectToggle">Mobile view</a></li> </ul> <ul id="footer-icons" class="noprint"> <li id="footer-copyrightico"><a href="https://wikimediafoundation.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/static/images/footer/wikimedia-button.svg" width="84" height="29" alt="Wikimedia Foundation" loading="lazy"></a></li> <li id="footer-poweredbyico"><a href="https://www.mediawiki.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/w/resources/assets/poweredby_mediawiki.svg" alt="Powered by MediaWiki" width="88" height="31" loading="lazy"></a></li> </ul> </footer> </div> </div> </div> <div class="vector-settings" id="p-dock-bottom"> <ul></ul> </div><script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-f69cdc8f6-rbglq","wgBackendResponseTime":192,"wgPageParseReport":{"limitreport":{"cputime":"0.696","walltime":"0.933","ppvisitednodes":{"value":2777,"limit":1000000},"postexpandincludesize":{"value":59159,"limit":2097152},"templateargumentsize":{"value":4466,"limit":2097152},"expansiondepth":{"value":14,"limit":100},"expensivefunctioncount":{"value":16,"limit":500},"unstrip-depth":{"value":1,"limit":20},"unstrip-size":{"value":70706,"limit":5000000},"entityaccesscount":{"value":1,"limit":400},"timingprofile":["100.00% 748.543 1 -total"," 13.46% 100.757 2 Template:Refn"," 12.81% 95.901 1 Template:Cite_journal"," 12.38% 92.703 1 Template:Acoustics"," 11.98% 89.704 1 Template:Navbox"," 11.85% 88.674 1 Template:Infobox_physical_quantity"," 11.50% 86.083 1 Template:Infobox"," 8.86% 66.317 2 Template:Reflist"," 8.19% 61.326 1 Template:Short_description"," 6.67% 49.915 2 Template:Cn"]},"scribunto":{"limitreport-timeusage":{"value":"0.441","limit":"10.000"},"limitreport-memusage":{"value":11415256,"limit":52428800},"limitreport-logs":"anchor_id_list = table#1 {\n [\"CITEREFBoreman\"] = 1,\n [\"CITEREFCondon2003\"] = 1,\n [\"CITEREFDavies1997\"] = 1,\n [\"CITEREFLombardi2007\"] = 1,\n [\"CITEREFNewellTiesinga2019\"] = 1,\n [\"CITEREFPilhofer2007\"] = 1,\n [\"CITEREFSerwayFaughn1989\"] = 1,\n [\"CITEREFYoung1999\"] = 1,\n [\"Definition\"] = 1,\n [\"Definitions\"] = 1,\n [\"Frequency_of_waves\"] = 1,\n [\"Unit\"] = 1,\n [\"Units\"] = 1,\n}\ntemplate_list = table#1 {\n [\"!\"] = 2,\n [\"=\"] = 1,\n [\"Acoustics\"] = 1,\n [\"Anchor\"] = 2,\n [\"Authority control\"] = 1,\n [\"Cite book\"] = 6,\n [\"Cite journal\"] = 1,\n [\"Cite report\"] = 1,\n [\"Cite web\"] = 6,\n [\"Cn\"] = 2,\n [\"Colend\"] = 1,\n [\"Cols\"] = 1,\n [\"Further\"] = 1,\n [\"Infobox physical quantity\"] = 1,\n [\"Main\"] = 1,\n [\"Main article\"] = 3,\n [\"Math\"] = 2,\n [\"Multiple image\"] = 1,\n [\"Music\"] = 1,\n [\"Nowrap\"] = 4,\n [\"Overline\"] = 1,\n [\"Pi\"] = 2,\n [\"Portal bar\"] = 1,\n [\"Redirect\"] = 1,\n [\"Reflist\"] = 2,\n [\"Refn\"] = 2,\n [\"See also\"] = 2,\n [\"Sfn\"] = 5,\n [\"Short description\"] = 1,\n [\"Ublist\"] = 2,\n [\"Val\"] = 4,\n [\"Wiktionary\"] = 1,\n}\narticle_whitelist = table#1 {\n}\n"},"cachereport":{"origin":"mw-web.codfw.main-f69cdc8f6-7gxbk","timestamp":"20241122140354","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"Frequency","url":"https:\/\/en.wikipedia.org\/wiki\/Frequency","sameAs":"http:\/\/www.wikidata.org\/entity\/Q11652","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q11652","author":{"@type":"Organization","name":"Contributors to Wikimedia projects"},"publisher":{"@type":"Organization","name":"Wikimedia Foundation, Inc.","logo":{"@type":"ImageObject","url":"https:\/\/www.wikimedia.org\/static\/images\/wmf-hor-googpub.png"}},"datePublished":"2001-05-10T21:39:38Z","dateModified":"2024-11-21T21:39:18Z","image":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/1\/1b\/%E0%B8%A5%E0%B8%B9%E0%B8%81%E0%B8%95%E0%B8%B8%E0%B9%89%E0%B8%A1%E0%B8%98%E0%B8%A3%E0%B8%A3%E0%B8%A1%E0%B8%8A%E0%B8%B2%E0%B8%95%E0%B8%B4.gif","headline":"number of occurrences or cycles per time"}</script> </body> </html>