Hi. I've been trying to learn the technical details of 8VSB modulation (and demodulation) used in North America's digital television broadcasts. But the only material I can find on the web are high-level simplified summaries of 8VSB modulation. At this point I'm interested in learning more about (1) the technical characteristics of a TV transmitter's filter that produces the final modulated 8VSB vestigial sideband RF signal, and (2) how to demodulate an 8VSB RF signal.
Do any of you guys know of a web site that provides the information I seek? Thanks.
Here are a couple links for you. Wayne Bretl did a lot of stuff on VSB at Zenith.
You "came through" again! Thanks a lot.
Twenty years ago such tutorials were pretty easy to come across, because it was all new and exciting. Now it's pretty widely recognized that there are no real advantages to 8VSB compared to anything else, except that it appealed to the old guys on the committee because it kind of resembled NTSC spectrally.
8VSB is essentially 8-ASK with the redundant half of the spectrum mostly filtered away, but not completely, hence "vesitigial", and small pilot tone added. It can be demodulated in a quadrature demodulator and then detected on one axis of the constellation. There are other tricks and other demodulation architectures, and I don't know for certain whether most implementations use a particular architecture or not.
The defining specification is ATSC A/53, and it used to be that some of the better modulation literature was associated with the IP block vendors, but I think the market is pretty small now or something, as I'm not seeing a lot out there now.
It does seem to be a bit elusive. There used to be some good papers, books, etc., and if I dig up a reference I'll pass it along.
Hi Eric. Quadrature demodulator huh? That answers one of my questions. Thanks for the information!!