Posted: Sat Jun 26, 2004 1:36 pm
I stumbled across this going through HDTV Magazine stuff... from 1999 I believe...
Motorola is the world's largest supplier of COFDM demodulation chips and is therefore uniquely qualified to comment on COFDM and 8-VSB demodulation. Extensive Comparisons of the 8-VSB modulation scheme with other technologies, including the COFDM method adopted by the Digital Video Broadcast (DVB) committee in Europe, were carried out by the ATSC, the FCC's advisory committee. The primary Key reasons for selecting 8-VSB for DTV/HDTV transmission in the United States include the ability to readily fit a full ATSC packet stream of 19.4 Mbps into a single 6 MHz channel, the channel bandwidth standard for terrestrial broadcasting in the United States; power efficiency, allowing broadcasters to achieve coverage equivalent to current analog signals with less transmitter power; reduced peak-to-average power ratio, which further reduces the required power rating of transmitter power amplifiers; and robust immunity to impulse noise interference.
While it was generally known that 8-VSB could be susceptible to multipath interference (interference from multiple signals arriving at an antenna at different times due to obstacles such as buildings or automobiles) in extreme circumstances, this was not judged to be an impeding factor. Recently, however, tests with off-the-air DTV signals in highly populated urban locations demonstrated reception problems with first generation receivers , whichthat were significant enough for some broadcasters to declare believe the FCC
Motorola is the world's largest supplier of COFDM demodulation chips and is therefore uniquely qualified to comment on COFDM and 8-VSB demodulation. Extensive Comparisons of the 8-VSB modulation scheme with other technologies, including the COFDM method adopted by the Digital Video Broadcast (DVB) committee in Europe, were carried out by the ATSC, the FCC's advisory committee. The primary Key reasons for selecting 8-VSB for DTV/HDTV transmission in the United States include the ability to readily fit a full ATSC packet stream of 19.4 Mbps into a single 6 MHz channel, the channel bandwidth standard for terrestrial broadcasting in the United States; power efficiency, allowing broadcasters to achieve coverage equivalent to current analog signals with less transmitter power; reduced peak-to-average power ratio, which further reduces the required power rating of transmitter power amplifiers; and robust immunity to impulse noise interference.
While it was generally known that 8-VSB could be susceptible to multipath interference (interference from multiple signals arriving at an antenna at different times due to obstacles such as buildings or automobiles) in extreme circumstances, this was not judged to be an impeding factor. Recently, however, tests with off-the-air DTV signals in highly populated urban locations demonstrated reception problems with first generation receivers , whichthat were significant enough for some broadcasters to declare believe the FCC