Article View: uk.tech.digital-tv
Article #210Re: Y [Luminance] signal on FM carrier wave.
From: Roderick Stewart
Date: Sat, 03 Nov 2007 03:09
Date: Sat, 03 Nov 2007 03:09
29 lines
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2759 bytes
In article <472bb331$0$25644$4c368faf@roadrunner.com>, Green Xenon [Radium] wrote: > >>Anyways, again, the following is interesting but only� > >>theoretically-possible. Not gonna happen with today's technology: > >> > >>The original Y signal is converted to QAM. This QAM signal is then� > >>broadcasted on an FM radio carrier wave whose base frequency is 300 Hz.� > >>300 Hz is the lowest ULF frequency and the lowest frequency used by� > >>telephones. > > >� > >� > > Not gonna happen at all. If you try to modulate a 300Hz carrier with 5MHz� > > video you'll end up with a mess. > > So decrease the 5 MHz frequency to a frequency that is low enough not to� > cause any distortion on a 300 Hz carrier. It's not a frequency, it's a *range* of frequencies. 5MHz is roughly the bandwidth required for a standard TV signal. You can't reduce it without reducing the picture quality, and if you reduce it too far it wouldn't be recogniseable as a picture at all. 5MHz bandwidth just doesn't fit in the bandwidth available with a 300Hz carrier. It's like trying to route motorway traffic down a garden path, or funnel a river through a drinking straw; it simply doesn't fit; it's fundamentally impossible. Several people have tried to explain this to you already but you keep hoping there will be some magic solution and there isn't one. Rod.
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X-Google-Thread: f928c,ab81b61b65e80ebd X-Google-Thread: ffcae,ab81b61b65e80ebd X-Google-Thread: 107cee,ab81b61b65e80ebd X-Google-Thread: f7d8a,ab81b61b65e80ebd X-Google-Thread: fdad6,ab81b61b65e80ebd X-Google-Attributes: gidf928c,gidffcae,gid107cee,gidf7d8a,gidfdad6,public,usenet X-Google-Language: ENGLISH,ASCII Path: arc1-ca.pugleaf.net!g2news2.google.com!news2.google.com!news.glorb.com!news-in-01.newsfeed.easynews.com!news-in-02.newsfeed.easynews.com!easynews.com!easynews!sn-xt-sjc-02!sn-xt-sjc-11!sn-xt-sjc-06!sn-post-sjc-01!supernews.com!corp.supernews.com!not-for-mail From: Roderick Stewart <escapetime@removethisbit.beeb.net> Newsgroups: uk.tech.digital-tv,uk.tech.broadcast,sci.electronics.misc,ba.broadcast,alt.radio.broadcasting Subject: Re: Y [Luminance] signal on FM carrier wave. Date: Sat, 03 Nov 2007 03:09:53 -0000 Organization: Posted via Supernews, http://www.supernews.com Message-ID: <VA.000001a6.004e9a7b@removethisbit.beeb.net> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Newsreader: Virtual Access Open Source http://www.virtual-access.org/ Reply-To: escapetime@removethisbit.beeb.net References: <472b9a39$0$20584$4c368faf@roadrunner.com> <VA.000001a5.026b23b2@removethisbit.beeb.net> <472bb331$0$25644$4c368faf@roadrunner.com> X-Complaints-To: abuse@supernews.com Lines: 30