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From: larry@kitty.UUCP (Larry Lippman)
Newsgroups: net.analog
Subject: Re: Re: Television over the telephone?  Is it possible?
Message-ID: <640@kitty.UUCP>
Date: Wed, 11-Dec-85 21:25:08 EST
Article-I.D.: kitty.640
Posted: Wed Dec 11 21:25:08 1985
Date-Received: Tue, 17-Dec-85 03:53:48 EST
References: <1148@gitpyr.UUCP> <382@unccvax.unccvax.UUCP> <743@petrus.UUCP>
Organization: Recognition Research Corp., Clarence, NY
Lines: 27

> > > Does anyone out there know if it is possible to transmit a [standard,
> > > full-motion color]
> > > television signal over a standard telephone line?  It seems to
> 
> By the way, the Shannon limit on a typical analog voice line is roughly 30
> kilobit/s. Of course, if the channel is being digitized and sent at 56 or 64
> kilobit/s, than that also sets an ultimate limit assuming all other noise
> sources could be removed.

	Transmission of television images over 3 KHz telephone lines has been
possible for a number of years using what are known as `slow-scan' converters.
Transmission of motion in real time is not possible, however.  I have used
equipment manufactured by Colorado Video Inc. of Boulder, Co. for this purpose;
CVI has a number of off-the-shelf slow-scan products with resolutions as great
as 1024 x 1024 pixels with 8 shades of grey.  I have also used scan converters
made by Hughes Aircraft Industrial Products Division (Carlsbad, Ca.) and by
Tektronix for this purpose.
	All of the above products are monochrome only, and I am not aware of
any off-the-shelf color scan converters for this purpose; however, there is no
reason why a color scan converter cannot be built.

===  Larry Lippman @ Recognition Research Corp., Clarence, New York        ===
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