{"id":1095,"date":"2018-12-20T08:00:38","date_gmt":"2018-12-20T13:00:38","guid":{"rendered":"http:\/\/blog.pasternack.com\/?p=1095"},"modified":"2018-12-18T09:00:05","modified_gmt":"2018-12-18T14:00:05","slug":"an-introduction-to-phase-locked-loops-and-rf-oscillators","status":"publish","type":"post","link":"\/blog\/rf-components\/rf-oscillators\/an-introduction-to-phase-locked-loops-and-rf-oscillators\/","title":{"rendered":"An Introduction to Phase-Locked-Loops and RF Oscillators"},"content":{"rendered":"<p>In most RF systems, the production, transmission, and reception of a radio frequency signal is accomplished by way of a transmitter which amplifies and modulates the signal and a receiver system which feeds the signal into the mixer circuits to enable frequency conversion and demodulation. An oscillator is a circuit that generates a repetitive waveform, often an amplifier, with positive feedback. To control the rate of waveform repetition, frequency selection is accomplished by using capacitors and inductors or resistor and capacitor combinations. Phase-Locked-Loops (PLL) are an important class of oscillator which compares the oscillator output with a reference signal and generates a control voltage based upon the phase difference. The control voltage is then used to \u201clock\u201d in the phase of the output signal.<\/p>\n<p><strong>Basic PLL Components<\/strong><\/p>\n<p>In other words, a PLL, is an electronic circuit that locks the phase of the output to the input by way of a negative feedback system that synchronizes the voltage controlled oscillator (VCO) output signal to the phase of a reference input signal. A PLL is made of a variable frequency oscillator which generates a periodic signal and a phase detector which compares the phase of that signal with the phase of the input periodic signal, adjusting the oscillator to keep the phases matched by way of a feedback loop. PLLs can be either analog or digital circuits and have a similar structure made up of four basic elements:<\/p>\n<p>\u2022 Phase comparator\/detector which is a circuit block component that detects and compares \u00a0a phase of two signals and generates a voltage based on the phase difference between the two signals; it generates the phase difference between input signals,<\/p>\n<p>\u2022 Loop filter that filters phase comparator output and filters out signals from the voltage controlled oscillator (VCO) line and moderates the stability of the PLL by canceling high frequencies and keeping DC components away from the error signal,<\/p>\n<p>\u2022 Voltage controlled oscillator (VCO) is the circuit block that generates the output radio frequency signal and is controlled by the error signal from the phase comparator\/detector, and<\/p>\n<p>\u2022 Feedback path which may include a frequency divider that directs the operational frequency band for the loop from the output signal to the phase detector.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-1096 \" src=\"\/blog\/wp-content\/uploads\/2018\/12\/PLL-Components-1024x258.png\" alt=\"\" width=\"516\" height=\"139\" \/><\/p>\n<p>&nbsp;<\/p>\n<p><strong>PLL Applications <\/strong><\/p>\n<p>PLLs are used in many radio frequency applications and are necessary components in radio frequency equipment including radio receivers, test equipment, demodulators, and frequency synthesizers. Applications include:<\/p>\n<p>\u2022 FM demodulation\/AM demodulation<\/p>\n<p>\u2022 Indirect frequency synthesizers.<\/p>\n<p>\u2022 Signal recovery<\/p>\n<p>\u2022 Timing distribution<\/p>\n<p><strong>Types of PLLs <\/strong><\/p>\n<p>\u2022 Analog Phase-Locked Loops (PLL\/APLL)<\/p>\n<p style=\"padding-left: 30px;\">First-Order PLL where the loop Filter frequency response is equal to single pole LP filter<\/p>\n<p style=\"padding-left: 30px;\">Second-Order PLL has greater flexibility and complexity<\/p>\n<p style=\"padding-left: 30px;\">Used in communication applications<\/p>\n<p>\u2022 Digital Phase-Locked Loops (DPLL\/ADPLL)<\/p>\n<p style=\"padding-left: 30px;\">A DPLL has a digital phase detector and an analog VCO and loop filter<\/p>\n<p style=\"padding-left: 30px;\">An All-Digital PLL (ADPLL) has all digital components<\/p>\n<p style=\"padding-left: 30px;\">Used in non-communication applications<\/p>\n<p>\u2022 Software Phase-Locked Loops (SPLL\/ASPLL)<\/p>\n<p style=\"padding-left: 30px;\">Mostly used for clock\/data recovery<\/p>\n<p style=\"padding-left: 30px;\">High flexibility such that many PLLs can be software implemented<\/p>\n<p>\u2022 Neuronal Phase-Locked Loops (NPLL)<\/p>\n<p style=\"padding-left: 30px;\">Artificial Neural Network (ANN) is a component in the feedback loop<\/p>\n<p style=\"padding-left: 30px;\">Used for automatic speech recognition and temporal coding in biomedical simulations of the brain<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In most RF systems, the production, transmission, and reception of a radio frequency signal is accomplished by way of a transmitter which amplifies and modulates the signal and a receiver system which feeds the signal into the mixer circuits to enable frequency conversion and demodulation. An oscillator is a circuit that generates a repetitive waveform, ..<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[441],"tags":[444,443,442],"class_list":["post-1095","post","type-post","status-publish","format-standard","hentry","category-rf-oscillators","tag-phase-locked-loops","tag-pll","tag-rf-oscillators"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.7 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>An Introduction to Phase-Locked-Loops and RF Oscillators - Pasternack Blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"\/blog\/rf-components\/rf-oscillators\/an-introduction-to-phase-locked-loops-and-rf-oscillators\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"An Introduction to Phase-Locked-Loops and RF Oscillators - Pasternack Blog\" \/>\n<meta property=\"og:description\" content=\"In most RF systems, the production, transmission, and reception of a radio frequency signal is accomplished by way of a transmitter which amplifies and modulates the signal and a receiver system which feeds the signal into the mixer circuits to enable frequency conversion and demodulation. An oscillator is a circuit that generates a repetitive waveform, [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"\/blog\/rf-components\/rf-oscillators\/an-introduction-to-phase-locked-loops-and-rf-oscillators\/\" \/>\n<meta property=\"og:site_name\" content=\"Pasternack Blog\" \/>\n<meta property=\"article:published_time\" content=\"2018-12-20T13:00:38+00:00\" \/>\n<meta property=\"og:image\" content=\"\/blog\/wp-content\/uploads\/2018\/12\/PLL-Components-1024x258.png\" \/>\n<meta name=\"author\" content=\"Peter McNeil\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Peter McNeil\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"3 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/blog.pasternack.com\\\/rf-components\\\/rf-oscillators\\\/an-introduction-to-phase-locked-loops-and-rf-oscillators\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/blog.pasternack.com\\\/rf-components\\\/rf-oscillators\\\/an-introduction-to-phase-locked-loops-and-rf-oscillators\\\/\"},\"author\":{\"name\":\"Peter McNeil\",\"@id\":\"https:\\\/\\\/blog.pasternack.com\\\/#\\\/schema\\\/person\\\/326df634ca01e2e320234e9aab876e02\"},\"headline\":\"An Introduction to Phase-Locked-Loops and RF Oscillators\",\"datePublished\":\"2018-12-20T13:00:38+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/blog.pasternack.com\\\/rf-components\\\/rf-oscillators\\\/an-introduction-to-phase-locked-loops-and-rf-oscillators\\\/\"},\"wordCount\":530,\"image\":{\"@id\":\"https:\\\/\\\/blog.pasternack.com\\\/rf-components\\\/rf-oscillators\\\/an-introduction-to-phase-locked-loops-and-rf-oscillators\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/blog.pasternack.com\\\/wp-content\\\/uploads\\\/2018\\\/12\\\/PLL-Components-1024x258.png\",\"keywords\":[\"Phase-Locked-Loops\",\"PLL\",\"RF Oscillators\"],\"articleSection\":[\"RF Oscillators\"],\"inLanguage\":\"en-US\"},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/blog.pasternack.com\\\/rf-components\\\/rf-oscillators\\\/an-introduction-to-phase-locked-loops-and-rf-oscillators\\\/\",\"url\":\"https:\\\/\\\/blog.pasternack.com\\\/rf-components\\\/rf-oscillators\\\/an-introduction-to-phase-locked-loops-and-rf-oscillators\\\/\",\"name\":\"An Introduction to Phase-Locked-Loops and RF Oscillators - Pasternack Blog\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/blog.pasternack.com\\\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\\\/\\\/blog.pasternack.com\\\/rf-components\\\/rf-oscillators\\\/an-introduction-to-phase-locked-loops-and-rf-oscillators\\\/#primaryimage\"},\"image\":{\"@id\":\"https:\\\/\\\/blog.pasternack.com\\\/rf-components\\\/rf-oscillators\\\/an-introduction-to-phase-locked-loops-and-rf-oscillators\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/blog.pasternack.com\\\/wp-content\\\/uploads\\\/2018\\\/12\\\/PLL-Components-1024x258.png\",\"datePublished\":\"2018-12-20T13:00:38+00:00\",\"author\":{\"@id\":\"https:\\\/\\\/blog.pasternack.com\\\/#\\\/schema\\\/person\\\/326df634ca01e2e320234e9aab876e02\"},\"breadcrumb\":{\"@id\":\"https:\\\/\\\/blog.pasternack.com\\\/rf-components\\\/rf-oscillators\\\/an-introduction-to-phase-locked-loops-and-rf-oscillators\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/blog.pasternack.com\\\/rf-components\\\/rf-oscillators\\\/an-introduction-to-phase-locked-loops-and-rf-oscillators\\\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/blog.pasternack.com\\\/rf-components\\\/rf-oscillators\\\/an-introduction-to-phase-locked-loops-and-rf-oscillators\\\/#primaryimage\",\"url\":\"https:\\\/\\\/blog.pasternack.com\\\/wp-content\\\/uploads\\\/2018\\\/12\\\/PLL-Components.png\",\"contentUrl\":\"https:\\\/\\\/blog.pasternack.com\\\/wp-content\\\/uploads\\\/2018\\\/12\\\/PLL-Components.png\",\"width\":1173,\"height\":296},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/blog.pasternack.com\\\/rf-components\\\/rf-oscillators\\\/an-introduction-to-phase-locked-loops-and-rf-oscillators\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"\u00a0\u00a0Pasternack Blog\",\"item\":\"https:\\\/\\\/blog.pasternack.com\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"An Introduction to Phase-Locked-Loops and RF Oscillators\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/blog.pasternack.com\\\/#website\",\"url\":\"https:\\\/\\\/blog.pasternack.com\\\/\",\"name\":\"Pasternack Blog\",\"description\":\"The Engineer&#039;s RF Source\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/blog.pasternack.com\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Person\",\"@id\":\"https:\\\/\\\/blog.pasternack.com\\\/#\\\/schema\\\/person\\\/326df634ca01e2e320234e9aab876e02\",\"name\":\"Peter McNeil\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/03b2ed3f5bdaec4dd3b873feef39d6c5c3b938be0ba443afd079064fc755279c?s=96&d=mm&r=g\",\"url\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/03b2ed3f5bdaec4dd3b873feef39d6c5c3b938be0ba443afd079064fc755279c?s=96&d=mm&r=g\",\"contentUrl\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/03b2ed3f5bdaec4dd3b873feef39d6c5c3b938be0ba443afd079064fc755279c?s=96&d=mm&r=g\",\"caption\":\"Peter McNeil\"},\"sameAs\":[\"http:\\\/\\\/blog.pasternack.com\"],\"url\":\"https:\\\/\\\/blog.pasternack.com\\\/author\\\/pete_mcneil\\\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"An Introduction to Phase-Locked-Loops and RF Oscillators - Pasternack Blog","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"\/blog\/rf-components\/rf-oscillators\/an-introduction-to-phase-locked-loops-and-rf-oscillators\/","og_locale":"en_US","og_type":"article","og_title":"An Introduction to Phase-Locked-Loops and RF Oscillators - Pasternack Blog","og_description":"In most RF systems, the production, transmission, and reception of a radio frequency signal is accomplished by way of a transmitter which amplifies and modulates the signal and a receiver system which feeds the signal into the mixer circuits to enable frequency conversion and demodulation. An oscillator is a circuit that generates a repetitive waveform, [&hellip;]","og_url":"\/blog\/rf-components\/rf-oscillators\/an-introduction-to-phase-locked-loops-and-rf-oscillators\/","og_site_name":"Pasternack Blog","article_published_time":"2018-12-20T13:00:38+00:00","og_image":[{"url":"\/blog\/wp-content\/uploads\/2018\/12\/PLL-Components-1024x258.png","type":"","width":"","height":""}],"author":"Peter McNeil","twitter_misc":{"Written by":"Peter McNeil","Est. reading time":"3 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"\/blog\/rf-components\/rf-oscillators\/an-introduction-to-phase-locked-loops-and-rf-oscillators\/#article","isPartOf":{"@id":"\/blog\/rf-components\/rf-oscillators\/an-introduction-to-phase-locked-loops-and-rf-oscillators\/"},"author":{"name":"Peter McNeil","@id":"\/blog\/#\/schema\/person\/326df634ca01e2e320234e9aab876e02"},"headline":"An Introduction to Phase-Locked-Loops and RF Oscillators","datePublished":"2018-12-20T13:00:38+00:00","mainEntityOfPage":{"@id":"\/blog\/rf-components\/rf-oscillators\/an-introduction-to-phase-locked-loops-and-rf-oscillators\/"},"wordCount":530,"image":{"@id":"\/blog\/rf-components\/rf-oscillators\/an-introduction-to-phase-locked-loops-and-rf-oscillators\/#primaryimage"},"thumbnailUrl":"\/blog\/wp-content\/uploads\/2018\/12\/PLL-Components-1024x258.png","keywords":["Phase-Locked-Loops","PLL","RF Oscillators"],"articleSection":["RF Oscillators"],"inLanguage":"en-US"},{"@type":"WebPage","@id":"\/blog\/rf-components\/rf-oscillators\/an-introduction-to-phase-locked-loops-and-rf-oscillators\/","url":"\/blog\/rf-components\/rf-oscillators\/an-introduction-to-phase-locked-loops-and-rf-oscillators\/","name":"An Introduction to Phase-Locked-Loops and RF Oscillators - Pasternack Blog","isPartOf":{"@id":"\/blog\/#website"},"primaryImageOfPage":{"@id":"\/blog\/rf-components\/rf-oscillators\/an-introduction-to-phase-locked-loops-and-rf-oscillators\/#primaryimage"},"image":{"@id":"\/blog\/rf-components\/rf-oscillators\/an-introduction-to-phase-locked-loops-and-rf-oscillators\/#primaryimage"},"thumbnailUrl":"\/blog\/wp-content\/uploads\/2018\/12\/PLL-Components-1024x258.png","datePublished":"2018-12-20T13:00:38+00:00","author":{"@id":"\/blog\/#\/schema\/person\/326df634ca01e2e320234e9aab876e02"},"breadcrumb":{"@id":"\/blog\/rf-components\/rf-oscillators\/an-introduction-to-phase-locked-loops-and-rf-oscillators\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["\/blog\/rf-components\/rf-oscillators\/an-introduction-to-phase-locked-loops-and-rf-oscillators\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"\/blog\/rf-components\/rf-oscillators\/an-introduction-to-phase-locked-loops-and-rf-oscillators\/#primaryimage","url":"\/blog\/wp-content\/uploads\/2018\/12\/PLL-Components.png","contentUrl":"\/blog\/wp-content\/uploads\/2018\/12\/PLL-Components.png","width":1173,"height":296},{"@type":"BreadcrumbList","@id":"\/blog\/rf-components\/rf-oscillators\/an-introduction-to-phase-locked-loops-and-rf-oscillators\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"\u00a0\u00a0Pasternack Blog","item":"\/blog\/"},{"@type":"ListItem","position":2,"name":"An Introduction to Phase-Locked-Loops and RF Oscillators"}]},{"@type":"WebSite","@id":"\/blog\/#website","url":"\/blog\/","name":"Pasternack Blog","description":"The Engineer&#039;s RF Source","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"\/blog\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Person","@id":"\/blog\/#\/schema\/person\/326df634ca01e2e320234e9aab876e02","name":"Peter McNeil","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/secure.gravatar.com\/avatar\/03b2ed3f5bdaec4dd3b873feef39d6c5c3b938be0ba443afd079064fc755279c?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/03b2ed3f5bdaec4dd3b873feef39d6c5c3b938be0ba443afd079064fc755279c?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/03b2ed3f5bdaec4dd3b873feef39d6c5c3b938be0ba443afd079064fc755279c?s=96&d=mm&r=g","caption":"Peter McNeil"},"sameAs":["http:\/\/blog.pasternack.com"],"url":"\/blog\/author\/pete_mcneil\/"}]}},"post_mailing_queue_ids":[],"_links":{"self":[{"href":"\/blog\/wp-json\/wp\/v2\/posts\/1095","targetHints":{"allow":["GET"]}}],"collection":[{"href":"\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"\/blog\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"\/blog\/wp-json\/wp\/v2\/comments?post=1095"}],"version-history":[{"count":8,"href":"\/blog\/wp-json\/wp\/v2\/posts\/1095\/revisions"}],"predecessor-version":[{"id":1104,"href":"\/blog\/wp-json\/wp\/v2\/posts\/1095\/revisions\/1104"}],"wp:attachment":[{"href":"\/blog\/wp-json\/wp\/v2\/media?parent=1095"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"\/blog\/wp-json\/wp\/v2\/categories?post=1095"},{"taxonomy":"post_tag","embeddable":true,"href":"\/blog\/wp-json\/wp\/v2\/tags?post=1095"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}