Archived from groups: alt.tv.tech.hdtv (More info?)
The NAB show is on in Las Vegas so there is a lot of chatter on OpenDTV
forum about what is happening with DTV stuff. Here is Mark Schubin on
the latest test of 8-VSB receivers.
Quote from OpenDTV forum Al...
>That's what I don't understand. Why keep pounding on results
>>obtained with 1st generation chips? Who cares?
>>
Mark Schubin responds...
Agreed. Let's not pound on the first-generation chips. Let's examine
the 5th generation.
Victor Tawil of the Association for Maximum Service Television (MSTV)
presented a paper today on tests MSTV conducted in the Washington, D.C.
area using the Zenith 5th-generation chip. The tests were conducted in
a portion of Virginia, right across the river from Washington, that has
tall buildings. The sites were selected because they were considered
tough, so the percentages of success don't reflect percentages of the
overall population. All of the tests were conducted outdoors.
In 14 of the 78 tests, the signals were considered below threshold. I
don't know whether that means below 15.5 dB C/N or below threshold for
the necessary equalization (the 5th-generation Zenith requires 24 dB C/N
for the Brazil-E ensemble). In any case, those 14 were deleted and did
not count against the percentages. Of the rest, there was a 65% success
rate (fewer than four hits in three minutes); measured the old way
(fewer than 50 hits in three minutes) there would have been an 86%
acceptable rate.
That's the fifth-generation, not the first. Those of us who
participated in the old Sinclair trials would be hard pressed to come up
with one site that failed. I had one: it was inside the shielded
transmitter building. At no other site -- and Sinclair gave me carte
blanche to choose -- was there a failure.
Oh, well.
The 5th generation is certainly better than the 4th, and Zenith is
working on a 6th.
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