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Article #162Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
From: Green Xenon [Radium]
Date: Sun, 23 Sep 2007 21:29
Date: Sun, 23 Sep 2007 21:29
30 lines
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2469 bytes
Hi: One major reason the luminance signals of television are broadcasted on an AM-carrier instead of FM is because FM requires large amounts of bandwidth. Is there a way to use FM video without hogging so much bandwidth? Quotes from http://groups.google.com/group/sci.electronics.basics/msg/0c013cf5371da8dc?hl=en& : >Multiple-level quadrature modulation, >"constellation modulation", >is most common for packing >lots of bits per Hz of bandwidth. >The more you pack, >the better the s/n ratio has to be. >http://en.wikipedia.org/wiki/Quadrature_amplitude_modulation >http://en.wikipedia.org/wiki/Constellation_diagram Does this mean that Quadrature Modulation and Constellation Modulation can -- at least in theory -- be applied to FM video so that excessive bandwidth is not needed? If so, then what would be the minimum radio-frequency required to transmit the video signal? Thanks, Radium
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X-Google-Thread: f928c,7e05cb8426dfb96,start X-Google-Thread: 1133a5,7e05cb8426dfb96,start X-Google-Thread: 115947,7e05cb8426dfb96,start X-Google-Thread: 1118be,7e05cb8426dfb96,start X-Google-Thread: ffcae,7e05cb8426dfb96,start X-Google-Thread: 107cee,7e05cb8426dfb96,start X-Google-Thread: f508e,7e05cb8426dfb96,start X-Google-Thread: f7d8a,7e05cb8426dfb96,start X-Google-Thread: fdad6,7e05cb8426dfb96,start X-Google-Attributes: gidf928c,gid1133a5,gid115947,gid1118be,gidffcae,gid107cee,gidf508e,gidf7d8a,gidfdad6,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: arc1-ca.pugleaf.net!g2news2.google.com!news1.google.com!border1.nntp.dca.giganews.com!nntp.giganews.com!nx01.iad01.newshosting.com!newshosting.com!post02.iad01!roadrunner.com!not-for-mail Date: Sun, 23 Sep 2007 14:29:50 -0700 From: "Green Xenon [Radium]" <glucegen1@excite.com> User-Agent: Mozilla/5.0 (Windows; U; Win98; en-US; rv:1.8b) Gecko/20050217 MIME-Version: 1.0 Newsgroups: uk.tech.digital-tv,rec.video.production,uk.media.tv.misc,sci.electronics.components,uk.tech.broadcast,sci.electronics.misc,aus.radio.broadcast,ba.broadcast,alt.radio.broadcasting Subject: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue? Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Lines: 30 Message-ID: <46f6d850$0$11068$4c368faf@roadrunner.com> Organization: Road Runner High Speed Online http://www.rr.com NNTP-Posting-Host: 75.84.20.87 X-Complaints-To: abuse@rr.com