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[Discuss-gnuradio] My First HDTV screenshot from USRP
From: |
mao mao |
Subject: |
[Discuss-gnuradio] My First HDTV screenshot from USRP |
Date: |
Sun, 2 Apr 2006 21:45:26 -0700 (PDT) |
Hi,
Finally, I got my first HDTV screenshot tonight. It's
from KTVU's "The Loop".
Here's how I did it:
1) Download ATSC stream off USRP with the following
parameters:
TVRX's rf freq = 725e6
USRP's center freq = 43.75e6
Decim = 8
TVRX's Gain = 88;
USRP's format = 0x300
Mux = 0xf0f0f0f0
See ktvu-complex.png for the FFT pic
2) Upsample 8Ms/s complex data to 40Ms/s complex data:
for every sample in the 8Ms/s data, add 4 zeros, then
followed by a lowpass filter.
3) Downsample 40Ms complex data to 20Ms/s complex
data:
remove every other sample from the 40Ms/s sample data
4) Frequency Translate the center frequency from 0Hz
to 5.75MHz
5) Keep the In-phase part of the 20Ms/s complex data
to get 20Ms/s real data:
See ktvu-real.png for the FFT pic
6) Feed the 20Ms/s real data into Gnuradio 0.9's
atsc_rx.
Voila! The finally screenshot is here: ktvu-The
Loop.jpg
Cheers!
Mao
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- [Discuss-gnuradio] My First HDTV screenshot from USRP,
mao mao <=
- Re: [Discuss-gnuradio] My First HDTV screenshot from USRP, Eric Blossom, 2006/04/03
- Re: [Discuss-gnuradio] My First HDTV screenshot from USRP, Charles Swiger, 2006/04/03
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- [Discuss-gnuradio] State of HDTV 2, Charles Swiger, 2006/04/05
- Re: [Discuss-gnuradio] State of HDTV 2, Eric Blossom, 2006/04/05
- Re: [Discuss-gnuradio] State of HDTV 2, Charles Swiger, 2006/04/06