<br><br><div class="gmail_quote">On Fri, May 9, 2008 at 7:33 PM, Dan Ritter <<a href="mailto:dsr-myth@tao.merseine.nu">dsr-myth@tao.merseine.nu</a>> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="Ih2E3d">On Fri, May 09, 2008 at 07:16:51PM -0400, Chris Ribe wrote:<br>
><br>
> This is true, but it would be much more difficult to provide multiple<br>
> streams from a single backend if you were feeding ATSC streams. Without the<br>
> ability to have independent frontends, such a system would be of limited<br>
> appeal. Also, consider that very few TVs have multiple ATSC tuners, so you<br>
> would need to work around the problem of still allowing those TVs to watch<br>
> off ait TV.<br>
<br>
</div>It's just a transport for video and audio; the frontend still<br>
needs to exist somewhere.</blockquote><div><br>Yes, so unless you have a very high monitor-to-frontend ratio, it isn't going to be cost competitive with a simple set top box that plugs into the network and outputs video. <br>
<br> <br></div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><br>
But as to your second point -- an ATSC channel is the same 6 MHz<br>
as an NTSC channel; once you've produced it, probably at a<br>
standard 'channel 3' setting, can't you use a $50 modulator<br>
(<a href="http://www.smarthome.com/7764.html" target="_blank">http://www.smarthome.com/7764.html</a> is the first to hand) to<br>
assign it to a dead channel that you create with a notch filter? Add<br>
another frontend, add another modulator. You should be able to<br>
handle four or five channels that way.<br>
<div class="Ih2E3d"></div></blockquote><div><br>No, that won't work. The modulation schemes are substantially incompatible. A 6Mhz NTSC band contains separate signals for luma, chroma, and audio. If you fed an RF modulator like the one you linked with a SMPTE-310 (baseband ATSC, roughly speaking) signal on the video input, it would output an undecodable mangled signal. <br>
<br>This isn't to say that an ATSC compatible RF modulator need be any more expensive than an NTSC model, just that currently available NTSC models wouldn't work. </div></div><br>-chris <br><br>-- <br>Chris Ribe<br>
TV/IT Engineer<br>WCJB-TV/DT Gainesville, FL<br>(352) 416 0648<br><a href="mailto:cribe@wcjb.com">cribe@wcjb.com</a>