Tom Barry wrote: > It appears that after FEC overhead in order to get mobile or good > multi path reception it would only have 4-5 mbps of payload. Did I > understand that correctly? If so then it obviously doesn't do > anything for HDTV reception since with MPEG-2 that is certainly > not enough for HD. You are looking at the turbo coding option, with 1/2 or 1/4 rate, which is by far the most onerous. It seems to me that you can use the SRS option to achieve good training in rapidly shifting echo, and still have plenty of good HDTV space available. And backward compatibility. > But I guess A-VSB is really only for mobile. I don't see that in the presentation. It's also for fixed reception. > Can anybody say what throughput can be expected for mobile > reception on a 6 mhz channels using the various DVB or OFDM > options? Is A-VSB competitive here? I see it as a more adjustable form of HM than COFDM offers. Meaning, the robust channel can be tuned to much lower bit rates than 4.5 Mb/s, leaving more room for HDTV, and the robust channel can also provide for very competitive C/N margins compared with COFDM. Look at the numbers. A 1/4 rate turbo-coded channel (but still using 8-VSB symbols), with single antenna, gives you 4.5 dB of C/N. This is similar to HM COFDM, QPSK in otherwise 16-QAM. But it's better than HM QPSK in 64-QAM. And with diversity antennas, you're down to the 1.7 dB C/N, but I don't have the COFDM numbers to compare that to. Overall, I'd say competitive, and that's what makes it interesting. ---- quote ----- .... SAMSUNG DOES NOT BELIEVE THAT RALEIGH CHANNEL PERFORMANCE WILL EVER HAPPEN BY JUST RECEIVE-SIDE ONLY IMPROVEMENTS. [emphasis added] ---- /quote --- > Is Raleigh channel performance something we need in gen-x receivers > to handle dynamic multi path properly? That and more. Rayleigh means that there is no dominant path. An example is Brazil E. I thought that 5th gen receivers were actually okay in this department. In any event, using the SRS technique should certainly help here, and that's fully backward compatible. Bert ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.