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#!/usr/bin/env python
#
# Copyright 2010 Free Software Foundation, Inc.
#
# This file is part of GNU Radio
#
# GNU Radio is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3, or (at your option)
# any later version.
#
# GNU Radio is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with GNU Radio; see the file COPYING. If not, write to
# the Free Software Foundation, Inc., 51 Franklin Street,
# Boston, MA 02110-1301, USA.
#
from gnuradio import gr, blks2
import sys
try:
import scipy
except ImportError:
print "Error: Program requires scipy (see: www.scipy.org)."
sys.exit(1)
try:
import pylab
except ImportError:
print "Error: Program requires matplotlib (see: matplotlib.sourceforge.net)."
sys.exit(1)
def main():
N = 1000000
fs = 8000
freqs = [100, 200, 300, 400, 500]
nchans = 7
sigs = list()
fmtx = list()
for fi in freqs:
s = gr.sig_source_f(fs, gr.GR_SIN_WAVE, fi, 1)
fm = blks2.nbfm_tx (fs, 4*fs, max_dev=10000, tau=75e-6)
sigs.append(s)
fmtx.append(fm)
syntaps = gr.firdes.low_pass_2(len(freqs), fs, fs/float(nchans)/2, 100, 100)
print "Synthesis Num. Taps = %d (taps per filter = %d)" % (len(syntaps),
len(syntaps)/nchans)
chtaps = gr.firdes.low_pass_2(len(freqs), fs, fs/float(nchans)/2, 100, 100)
print "Channelizer Num. Taps = %d (taps per filter = %d)" % (len(chtaps),
len(chtaps)/nchans)
filtbank = gr.pfb_synthesis_filterbank_ccf(nchans, syntaps)
channelizer = blks2.pfb_channelizer_ccf(nchans, chtaps)
noise_level = 0.01
head = gr.head(gr.sizeof_gr_complex, N)
noise = gr.noise_source_c(gr.GR_GAUSSIAN, noise_level)
addnoise = gr.add_cc()
snk_synth = gr.vector_sink_c()
tb = gr.top_block()
tb.connect(noise, (addnoise,0))
tb.connect(filtbank, head, (addnoise, 1))
tb.connect(addnoise, channelizer)
tb.connect(addnoise, snk_synth)
snk = list()
for i,si in enumerate(sigs):
tb.connect(si, fmtx[i], (filtbank, i))
for i in xrange(nchans):
snk.append(gr.vector_sink_c())
tb.connect((channelizer, i), snk[i])
tb.run()
if 1:
channel = 1
data = snk[channel].data()[1000:]
f1 = pylab.figure(1)
s1 = f1.add_subplot(1,1,1)
s1.plot(data[10000:10200] )
s1.set_title(("Output Signal from Channel %d" % channel))
fftlen = 2048
winfunc = scipy.blackman
#winfunc = scipy.hamming
f2 = pylab.figure(2)
s2 = f2.add_subplot(1,1,1)
s2.psd(data, NFFT=fftlen,
Fs = nchans*fs,
noverlap=fftlen/4,
window = lambda d: d*winfunc(fftlen))
s2.set_title(("Output PSD from Channel %d" % channel))
f3 = pylab.figure(3)
s3 = f3.add_subplot(1,1,1)
s3.psd(snk_synth.data()[1000:], NFFT=fftlen,
Fs = nchans*fs,
noverlap=fftlen/4,
window = lambda d: d*winfunc(fftlen))
s3.set_title("Output of Synthesis Filter")
pylab.show()
if __name__ == "__main__":
main()
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