From 8a0ead8481c2418560dd98d8bb64c82842a76bcc Mon Sep 17 00:00:00 2001
From: Tom Rondeau <trondeau@vt.edu>
Date: Tue, 19 Jun 2012 21:32:37 -0400
Subject: filter: Moved over PFB examples.
---
gr-filter/examples/reconstruction.py | 164 +++++++++++++++++++++++++++++++++++
1 file changed, 164 insertions(+)
create mode 100755 gr-filter/examples/reconstruction.py
(limited to 'gr-filter/examples/reconstruction.py')
diff --git a/gr-filter/examples/reconstruction.py b/gr-filter/examples/reconstruction.py
new file mode 100755
index 0000000000..9e38f3669c
--- /dev/null
+++ b/gr-filter/examples/reconstruction.py
@@ -0,0 +1,164 @@
+#!/usr/bin/env python
+#
+# Copyright 2010,2012 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, digital
+from gnuradio import filter
+
+try:
+ import scipy
+ from scipy import fftpack
+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)
+
+fftlen = 8192
+
+def main():
+ N = 10000
+ fs = 2000.0
+ Ts = 1.0/fs
+ t = scipy.arange(0, N*Ts, Ts)
+
+ # When playing with the number of channels, be careful about the filter
+ # specs and the channel map of the synthesizer set below.
+ nchans = 10
+
+ # Build the filter(s)
+ bw = 1000
+ tb = 400
+ proto_taps = filter.firdes.low_pass_2(1, nchans*fs,
+ bw, tb, 80,
+ filter.firdes.WIN_BLACKMAN_hARRIS)
+ print "Filter length: ", len(proto_taps)
+
+
+ # Create a modulated signal
+ npwr = 0.01
+ data = scipy.random.randint(0, 256, N)
+ rrc_taps = filter.firdes.root_raised_cosine(1, 2, 1, 0.35, 41)
+
+ src = gr.vector_source_b(data.astype(scipy.uint8).tolist(), False)
+ mod = digital.bpsk_mod(samples_per_symbol=2)
+ chan = gr.channel_model(npwr)
+ rrc = filter.fft_filter_ccc(1, rrc_taps)
+
+ # Split it up into pieces
+ channelizer = filter.pfb.channelizer_ccf(nchans, proto_taps, 2)
+
+ # Put the pieces back together again
+ syn_taps = [nchans*t for t in proto_taps]
+ synthesizer = filter.pfb_synthesizer_ccf(nchans, syn_taps, True)
+ src_snk = gr.vector_sink_c()
+ snk = gr.vector_sink_c()
+
+ # Remap the location of the channels
+ # Can be done in synth or channelizer (watch out for rotattions in
+ # the channelizer)
+ synthesizer.set_channel_map([ 0, 1, 2, 3, 4,
+ 15, 16, 17, 18, 19])
+
+ tb = gr.top_block()
+ tb.connect(src, mod, chan, rrc, channelizer)
+ tb.connect(rrc, src_snk)
+
+ vsnk = []
+ for i in xrange(nchans):
+ tb.connect((channelizer,i), (synthesizer, i))
+
+ vsnk.append(gr.vector_sink_c())
+ tb.connect((channelizer,i), vsnk[i])
+
+ tb.connect(synthesizer, snk)
+ tb.run()
+
+ sin = scipy.array(src_snk.data()[1000:])
+ sout = scipy.array(snk.data()[1000:])
+
+
+ # Plot original signal
+ fs_in = nchans*fs
+ f1 = pylab.figure(1, figsize=(16,12), facecolor='w')
+ s11 = f1.add_subplot(2,2,1)
+ s11.psd(sin, NFFT=fftlen, Fs=fs_in)
+ s11.set_title("PSD of Original Signal")
+ s11.set_ylim([-200, -20])
+
+ s12 = f1.add_subplot(2,2,2)
+ s12.plot(sin.real[1000:1500], "o-b")
+ s12.plot(sin.imag[1000:1500], "o-r")
+ s12.set_title("Original Signal in Time")
+
+ start = 1
+ skip = 4
+ s13 = f1.add_subplot(2,2,3)
+ s13.plot(sin.real[start::skip], sin.imag[start::skip], "o")
+ s13.set_title("Constellation")
+ s13.set_xlim([-2, 2])
+ s13.set_ylim([-2, 2])
+
+ # Plot channels
+ nrows = int(scipy.sqrt(nchans))
+ ncols = int(scipy.ceil(float(nchans)/float(nrows)))
+
+ f2 = pylab.figure(2, figsize=(16,12), facecolor='w')
+ for n in xrange(nchans):
+ s = f2.add_subplot(nrows, ncols, n+1)
+ s.psd(vsnk[n].data(), NFFT=fftlen, Fs=fs_in)
+ s.set_title("Channel {0}".format(n))
+ s.set_ylim([-200, -20])
+
+ # Plot reconstructed signal
+ fs_out = 2*nchans*fs
+ f3 = pylab.figure(3, figsize=(16,12), facecolor='w')
+ s31 = f3.add_subplot(2,2,1)
+ s31.psd(sout, NFFT=fftlen, Fs=fs_out)
+ s31.set_title("PSD of Reconstructed Signal")
+ s31.set_ylim([-200, -20])
+
+ s32 = f3.add_subplot(2,2,2)
+ s32.plot(sout.real[1000:1500], "o-b")
+ s32.plot(sout.imag[1000:1500], "o-r")
+ s32.set_title("Reconstructed Signal in Time")
+
+ start = 2
+ skip = 4
+ s33 = f3.add_subplot(2,2,3)
+ s33.plot(sout.real[start::skip], sout.imag[start::skip], "o")
+ s33.set_title("Constellation")
+ s33.set_xlim([-2, 2])
+ s33.set_ylim([-2, 2])
+
+ pylab.show()
+
+
+if __name__ == "__main__":
+ try:
+ main()
+ except KeyboardInterrupt:
+ pass
+
--
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