ATSC real-time application?

I am quite interested in the ATSC project due to some previous HDTV R&D
experience.
I am not quite sure about the current status of this project.
According to my understanding, ATSC has a very high throughput
requirement
with a symbol rate=10.72M / sec
Considering this high symbol rate and the computationally intense
algorithm
in RS decoder, Equalizer, Viterbi, etc., I am just wondering how
powerful
the computer has to be to process all these in realtime?
What kind of computers have been used in the gr-atsc project to process
realtime HDTV?
Recalling that a PC do not have the luxury of parallel computation.
For instance, a 4.0G CPU has to process one symbol in 400 clock
durations,
which seems to be not enough.
Thanks

Kyle Z.

On Sat, 2006-10-28 at 01:19 +1000, Kyle Z. wrote:

I am quite interested in the ATSC project due to some previous HDTV
R&D experience.
I am not quite sure about the current status of this project.
According to my understanding, ATSC has a very high throughput
requirement with a symbol rate=10.72M / sec
Considering this high symbol rate and the computationally intense
algorithm in RS decoder, Equalizer, Viterbi, etc., I am just wondering
how powerful the computer has to be to process all these in realtime?
What kind of computers have been used in the gr-atsc project to
process realtime HDTV?

None that I know of. With a 4-cpu 2Ghz system with the processes
spread out so the total utilization is 80%, there’s still a maybe
(rough guess) 7:1 process-time to real-time ratio. At least I seem
to remember taking at least 14 hours to process a 2 hour movie. The
bottleneck (cpu running 99%) was still the gnuradio0.9 part from
bit-timing-loop to field-sync-demux. Once atsc is completely ported to
the 2.x framework more can be done to optimize things.

Recalling that a PC do not have the luxury of parallel computation. For
instance, a 4.0G CPU has to process one symbol in 400 clock durations,
which seems to be not enough.

That’s the question - is the most intensive atsc function too
much for a commonly available cpu to process in realtime?

On Fri, 2006-10-27 at 11:11 -0500, Meiners, Jason wrote:

Has anyone benchmarked the ATSC encode function? Can this be done in
real time? Decode is always harder to do than encode :slight_smile:

Actually, an HDTV transmitter function might fulfill a niche that
couldn’t be easily implemented otherwise. A pchdtv HD-5500 is
$130, but these can’t be cheap:

http://www.broadcast.harris.com/product_portfolio/product_details.asp?sku=WWWAPEX

Has anyone benchmarked the ATSC encode function? Can this be done in
real time? Decode is always harder to do than encode :slight_smile:

Will an RFX400 pass a 6MHz wide signal? (AD834X mixer)

Easily

Matt

On Fri, 2006-10-27 at 19:47 -0400, Charles S. wrote:

Actually it looks pretty good - the randomizer, Reed-Solomon encoder,
interleaver and Trellis Encoder already work in 2.x, all we need to
run in 0.9 is Field Sync Mux, Symbol Mapper and Weaver Mod head/tail -
drive a basic-TX and suitable analog upconverter and you have a low
power hi-def tv station :wink:

Will an RFX400 pass a 6MHz wide signal? (AD834X mixer)

Here’s the output of 0.9 atsc_tx re-sending some mpeg captured from a
local station (via a disk file, not realtime yet):

http://webpages.charter.net/cswiger/photos/atsc_tx_09.jpg

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