John Shutt wrote: > > If you only use 25 percent more FEC, you are not creating a > > much more robust bitstream, John. But look at your > > documentation and see that they mention 1/2 or 2/3 FEC > > (presumably total) and 16-QAM or QPSK. Not 64-QAM. > > Creating a more robust stream for mobile is optional. COFDM > already has quite an advantage in receviabilty. It is the > time slicing that saves power. John, I understand about time slicing. The bit rate question is the one that didn't make sense to me. Your complaint was about how much b/s you "lose" compared with a single wide channel. Same-o same-o with any scheme. For reception with cell phones, unless you count of very high C/N, you will have to have a more robust stream than 64-QAM 3/4 FEC and 1/16 GI, simply because the antenna is going to be far from ideal. So if you want to allow reception on cell phones of a special stream to be market-wide, you're going to want a more robust stream than the wide stream meant for fixed receivers. > You could use HM modulation, or you could just stay with a > single modulation method. for the same data hit, you get a > better received signal for the entire stream. Whatever approach you use, the total bit rate will be less than it was before. The same applies to HM. But again, this assumes that the robustness of the wide stream is to be retained. It's not fair to complain about features in one system that are basically identical to those of another system. The fundamental difference between E-VSB and the other methods is that E-VSB relies on much more FEC, rather than also relying on reduced constellation. How these approaches compare would be interesting to see in real life. 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.