Newsgroups: comp.robotics
Path: brunix!news.Brown.EDU!noc.near.net!gateway-gw!newshost!wpns
From: wpns@newshost.pictel.com (Willie Smith)
Subject: Re: Help! Looking for a Spread Spectrum Video Link
Message-ID: <1993Dec19.170454.6033@newshost.pictel.com>
Organization: PictureTel Corporation
References: <CI4xLG.AFD@freenet.carleton.ca> <1993Dec16.173053.17135@mksol.dseg.ti.com>
Date: Sun, 19 Dec 1993 17:04:54 GMT
Lines: 26

strohm@mksol.dseg.ti.com (john r strohm) writes:
(Wayne Mercer) writes:
>>We are looking for a Spread Spectrum video link for a tele-robotics
>>application.  If you know of a company that makes such a beast,
>>we would appreciate your sharing the knowledge.

>Plain video is about 4 MHz wide.  Spreading it out, you are looking at
>more like 40 MHz wide, or more: your transmitter and receiver RF paths
>have to be flat across that bandwidth.  That is a pretty tall order.

Well, unless you use video compression (where you can get the bitrate
down to around a hundred kilobits, hence around a hundred kilohertz of
bandwidth), video _does_ take a lot of bandwidth.  However, satellite
TV is FM video with very wide bandwidth, so the hardware exists.  I'd
have to second John's question though:

>Why does it have to be Spread Spectrum?

How far do you have to transmit?  For really short distances I've used
a 900 MHz VCR extender gizmo, but for the big robot I use Amateur TV
at 915 MHz.  If it's non-commercial in nature, try amateur radio!


-- 
Willie Smith	wpns@pictel.com		N1JBJ@amsat.org
She's writing a formal letter of complaint to the Internet Administration!
