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[Discuss-gnuradio] SSB demodulation
From: |
cswiger |
Subject: |
[Discuss-gnuradio] SSB demodulation |
Date: |
Wed, 8 Sep 2004 09:07:11 -0400 (EDT) |
Hi All - I'm making wild stabs are writing modules to demod SSB
with REAL+IMAG or REAL-IMAG for upper and lower sideband, simply
by cloning David Carr's gr_complex_mag module:
gr_complex_mag:
for (int i = 0; i < noutput_items; i++){
float ans = std::abs (in[i]);
out[i] = ans;
I have compiled gr_complex_sum:
for (int i = 0; i < noutput_items; i++){
gr_complex in_c = in[i];
float ans = in_c.real() + in_c.imag();
out[i] = ans;
and gr_complex_dif is same except for in_c.real() - in_c.imag();
Now testing those out I'm getting a lot of noise and getting audio
out on both sidebands, setting the radio for 950Khz and listening
to an unmodulated sine 1K above and below 950Khz I get these:
http://www.widomaker.com/~cswiger/949Khz_sum.jpg
http://www.widomaker.com/~cswiger/949Khz_dif.jpg
http://www.widomaker.com/~cswiger/951Khz_sum.jpg
http://www.widomaker.com/~cswiger/951Khz_dif.jpg
Anything obviously wrong that accounts for the noise and signal
on both sidebands? The tones are correct, 1Khz (32 points/cycle
at 32Ksps).
Tks
--Chuck
- [Discuss-gnuradio] SSB demodulation,
cswiger <=