[opendtv] Re: Specs for coupon program-compliant STBs
- From: Richard Hollandsworth <holl_ands@xxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Mon, 12 Mar 2007 18:57:35 -0700 (PDT)
Seems NTIA backed off Field Ensemble spec requirement (only 30 out of 50) wrt
current capabilities.
ATI submitted test results for two of their (unnamed) ATSC Demodulators (the
best Receiver "D" was released in mid-2004):
[Sounds like Xilleon (e.g. 240) and Theater chips....]
http://gullfoss2.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6517693762
The two ATI products ("C" and "D") successfully decoded (two or fewer errors)
37 to 39
out of 47 (valid) field ensembles, so they easily exceed NTIA requirement.
If you look at Fig 6-1 on pg 6-6, you'll see that there are two distinctive
groups.
Ten of the HDTV's tested successfully decoded 35 to 39
field ensembles.
Hmmm---seems to be in the ballpark of the ATI Receiver "C" and "D" test
results...
Most of the other HDTV's and ALL of the tested OTA STB's were in the low
performance
group where the best decoded only 8 to 11, except for one HDTV and
one OTA STB that mustered 14 to 16.
Since the LG LST-4200A was generally recognized as being the "best performer"
OTA STBs
at the time of the test, I have speculated that it's LGDT3302 may be the
"better" OTA STB.
And the LGDT3303 5thGen chip is hopefully in one or more of the better
performance HDTV's.
Since the FCC report states that one OTA STB had an EIA/CEA-909 Smart Antenna
interface, one of the lower performing OTA STB's must be my Sylvania 6900DTE
(aka Funai STB-400) with the older ATI NXT2004 ATSC Decoder chip.
PS: I have never seen anything other than the CRC Test Report wrt Samsung
"Gemini"
ATSC Decoder chip (38 of 50 passed)....with ALPS tuner.
I think "Gemini" was a "code name" for the ATI Xilleon 240H (Receiver "C"?),
as used in the Samsung STB-H260F OTA STB....which uses ALPS TDQU3-001A tuner.
PS: The Samsung S5H1409/1410 chips are recent Samsung chips, but the initial
data sheets (rev 1.0) are dtg Mar2005 and CRC Test Report is dtg Aug2005...too
soon...
CRC also found -45 to +50 usec multipath range vice -37 to + 47 usec claimed
for Samsung chips.
holl_ands
==========================================
"Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx> wrote: Mark Aitken wrote:
> the -5dBm is for a single signal, not multiple. The concerns regarding
> front end overload do not change. It would have been nice to address
> that one (wonder if they supply a cheap pad...which does not solve
> everything but can be a good first step...Zenith used to supply them
> with earlier DTV devices...). Could be worse (NO requirement), but
> certainly a starting place of some known level of performance...
Look on the bright side. At least it's 3 dB better than A/74 recommends.
It's also 10 dB better than NORDIG recommends.
The 5th gen Zenith, coupled to whatever tuner it was tested with by the
CRC, goes between -2.3 dBm to -78.5 dBm, so the dynamic range is shifted
up compared with this NTIA spec. Not enough sensitivity, in the version
tested in 2003.
The Samsung Gemini as tested by the CRC goes from at least +1.5 dBm (the
limit of CRC's test equipment) to -84.7 dBm, which is beyond A/74 and
beyond the NTIA spec on both sides.
Also, the Gemini passes the field ensembles test, by their criterion (no
glitches in 30 of the 50 environments). No info on the Zenith 5th gen
wrt these ensembles.
Too bad the CRC didn't test the ATI Xilleon 240, which seems to be the
popular low-cost choice.
Although this dynamic range question really only applies to the tuner.
The Xceive 5000 and the Microtune 2131 can both handle the needed
dynamic range.
Bert
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