{"id":15278,"date":"2025-04-17T10:10:33","date_gmt":"2025-04-17T02:10:33","guid":{"rendered":"https:\/\/www.premlink.net\/?p=15278"},"modified":"2026-04-03T13:57:26","modified_gmt":"2026-04-03T05:57:26","slug":"%d1%87%d1%82%d0%be-%d1%82%d0%b0%d0%ba%d0%be%d0%b5-%d0%be%d1%82%d0%bd%d0%be%d1%88%d0%b5%d0%bd%d0%b8%d0%b5-%d0%bd%d0%b5%d1%81%d1%83%d1%89%d0%b5%d0%b9-%d0%ba-%d1%88%d1%83%d0%bc%d1%83-cnr","status":"publish","type":"post","link":"https:\/\/www.premlink.net\/ru\/what-is-carrier-to-noise-ratio-cnr\/","title":{"rendered":"\u041f\u043e\u043d\u0438\u043c\u0430\u043d\u0438\u0435 \u043e\u0442\u043d\u043e\u0448\u0435\u043d\u0438\u044f \u043d\u0435\u0441\u0443\u0449\u0435\u0439 \u043a \u0448\u0443\u043c\u0443 (CNR) \u0432 \u043a\u0430\u0431\u0435\u043b\u044c\u043d\u043e\u043c \u0442\u0435\u043b\u0435\u0432\u0438\u0434\u0435\u043d\u0438\u0438: \u0424\u043e\u0440\u043c\u0443\u043b\u044b, \u0440\u0430\u0441\u0447\u0435\u0442\u044b \u0438 \u043e\u043f\u0442\u0438\u043c\u0438\u0437\u0430\u0446\u0438\u044f"},"content":{"rendered":"\n<figure class=\"wp-block-image size-full\"><img fetchpriority=\"high\" decoding=\"async\" width=\"600\" height=\"365\" src=\"https:\/\/www.premlink.net\/wp-content\/uploads\/2025\/04\/CNR.jpg\" alt=\"Carrier-to-Noise Ratio\" class=\"wp-image-16618\" srcset=\"https:\/\/www.premlink.net\/wp-content\/uploads\/2025\/04\/CNR.jpg 600w, https:\/\/www.premlink.net\/wp-content\/uploads\/2025\/04\/CNR-500x304.jpg 500w, https:\/\/www.premlink.net\/wp-content\/uploads\/2025\/04\/CNR-300x183.jpg 300w, https:\/\/www.premlink.net\/wp-content\/uploads\/2025\/04\/CNR-18x12.jpg 18w, https:\/\/www.premlink.net\/wp-content\/uploads\/2025\/04\/CNR-480x292.jpg 480w\" sizes=\"(max-width: 600px) 100vw, 600px\" \/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">What is Carrier-to-Noise Ratio (CNR)? <\/h2>\n\n\n\n<p>Carrier-to-Noise Ratio (CNR) is a critical measurement of the noise power in a specific bandwidth relative to the video carrier level in the same bandwidth for NTSC\/PAL Channels. Carrier-to-Noise Ratio (CNR) is typically specified over a 4MHz band\u2014the video portion of the channel. In modern HFC (Hybrid Fiber-Coaxial) and FTTH networks, CNR is a decisive factor in determining the clarity of analog and digital video signals delivered to the end-user.<\/p>\n\n\n\n<p>Carrier-to-Noise Ratio (CNR) is an important parameter for high-performance CATV products, such as <strong><a href=\"https:\/\/www.premlink.net\/optical-node\/\">optical receiver<\/a>, <a href=\"https:\/\/www.premlink.net\/catv-edfa-eydfa\/\">EDFA\/EYDFA amplifier<\/a>, and optical transmitter<\/strong>.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" style=\"font-size:19px\"><strong>How to Calculate Carrier-to-Noise Ratio (CNR)?<\/strong><\/h3>\n\n\n\n<p>CNR adds on a power basis. If the amplifier input level and the <strong>Noise Figure (NF)<\/strong> are known, CNR can be calculated with the following formulas.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" style=\"font-size:19px\"><strong>CNR for a Single Amplifier:<\/strong> <\/h3>\n\n\n\n<p>CNR = Input Level (dBmV) + 59 \u2013 NF <\/p>\n\n\n\n<p><em>(NF = Noise Figure)<\/em><\/p>\n\n\n\n<h3 class=\"wp-block-heading\" style=\"font-size:19px\"><strong>To add similar CNR figures (Cascade Optimization):<\/strong> <\/h3>\n\n\n\n<p>CNRs = CNR\u2080 \u2013 10logN <em>(N = Number of CNR Figures)<\/em><\/p>\n\n\n\n<h3 class=\"wp-block-heading\" style=\"font-size:19px\"><strong>To add dissimilar CNR figures:<\/strong> <\/h3>\n\n\n\n<p>CNRs = \u221210 log\u2081\u2080 [ 10^(-CNR\u2081\/10) + 10^(-CNR\u2082\/10) + &#8230; + 10^(-CNR\u2099\/10) ]<\/p>\n\n\n\n<p><strong>Where:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>CNR\u2080, CNRn:<\/strong> CNR (dB) of a Single Amplifier (n=1, 2, 3,\u2026N)<\/li>\n\n\n\n<li><strong>CNRs:<\/strong> Total System CNR (dB)<\/li>\n\n\n\n<li><strong>59:<\/strong> Thermal Noise in 4MHz Bandwidth (dBmV)<\/li>\n\n\n\n<li><strong>N:<\/strong> Number of Amplifiers in Cascade<\/li>\n\n\n\n<li><strong>NF:<\/strong> Noise Figure (dB)<\/li>\n<\/ul>\n\n\n\n<p>Note: Input level must be in dBmV. If the Noise Figure does not include the equalizer at the amplifier input, it is recommended to add 1dB to the Noise Figure, which will decrease the overall CNR by approximately 1dB. Remember: Every time you double a cascade of similar amplifiers, the CNR degrades by 3dB.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" style=\"font-size:26px\"><strong>The Impact of CNR on Modern RF Overlay &amp; XGSPON Networks<\/strong><\/h2>\n\n\n\n<p>In the era of Next-Gen PON (XGSPON and 50G-PON), Carrier-to-Noise Ratio (CNR) remains the &#8220;Gold Standard&#8221; for RF Video Overlay quality. When integrating 1550nm video signals with high-speed data, maintaining a high CNR is essential to prevent &#8220;snow&#8221; or graininess in analog channels and &#8220;tiling&#8221; or bit errors in digital QAM channels.<\/p>\n\n\n\n<p>Key factors affecting CNR in FTTH deployments include:<\/p>\n\n\n\n<ol start=\"1\" class=\"wp-block-list\">\n<li>Optical Launch Power: Higher power from the EYDFA generally improves CNR, but must be balanced against fiber non-linearities.<\/li>\n\n\n\n<li>Receiver Responsivity: The quality of the photodiode in the optical receiver directly dictates the CNR threshold.<\/li>\n\n\n\n<li>WDM Isolation: Superior isolation in WDM PON EDFAs ensures that data wavelengths do not leak into the video spectrum, preserving the carrier integrity.<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\" style=\"font-size:26px\"><strong>CNR vs. MER: What is the Difference?<\/strong><\/h2>\n\n\n\n<p>While Carrier-to-Noise Ratio (CNR) measures the ratio of the carrier to the noise floor before demodulation, MER (Modulation Error Ratio) is used for digital signals (<a href=\"https:\/\/info.support.huawei.com\/info-finder\/encyclopedia\/en\/QAM.html\" target=\"_blank\" rel=\"noopener\">QAM<\/a>) to measure the &#8220;health&#8221; of the constellation. For engineers, a stable CNR is the foundation\u2014if the CNR is poor at the optical level, the MER will inevitably fail at the subscriber&#8217;s Set-Top Box (STB).<\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>What is Carrier-to-Noise Ratio (CNR)? Carrier-to-Noise Ratio (CNR) is a critical measurement of the noise power in a specific bandwidth [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":15279,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[46],"tags":[],"class_list":["post-15278","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-knowledge-center"],"_links":{"self":[{"href":"https:\/\/www.premlink.net\/ru\/wp-json\/wp\/v2\/posts\/15278","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.premlink.net\/ru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.premlink.net\/ru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.premlink.net\/ru\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.premlink.net\/ru\/wp-json\/wp\/v2\/comments?post=15278"}],"version-history":[{"count":0,"href":"https:\/\/www.premlink.net\/ru\/wp-json\/wp\/v2\/posts\/15278\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.premlink.net\/ru\/wp-json\/wp\/v2\/media\/15279"}],"wp:attachment":[{"href":"https:\/\/www.premlink.net\/ru\/wp-json\/wp\/v2\/media?parent=15278"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.premlink.net\/ru\/wp-json\/wp\/v2\/categories?post=15278"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.premlink.net\/ru\/wp-json\/wp\/v2\/tags?post=15278"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}