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/resampler.py | 128 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 128 insertions(+)
create mode 100755 gr-filter/examples/resampler.py
(limited to 'gr-filter/examples/resampler.py')
diff --git a/gr-filter/examples/resampler.py b/gr-filter/examples/resampler.py
new file mode 100755
index 0000000000..395e095cbd
--- /dev/null
+++ b/gr-filter/examples/resampler.py
@@ -0,0 +1,128 @@
+#!/usr/bin/env python
+#
+# Copyright 2009,2012 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
+from gnuradio import filter
+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)
+
+class mytb(gr.top_block):
+ def __init__(self, fs_in, fs_out, fc, N=10000):
+ gr.top_block.__init__(self)
+
+ rerate = float(fs_out) / float(fs_in)
+ print "Resampling from %f to %f by %f " %(fs_in, fs_out, rerate)
+
+ # Creating our own taps
+ taps = gr.firdes.low_pass_2(32, 32, 0.25, 0.1, 80)
+
+ self.src = gr.sig_source_c(fs_in, gr.GR_SIN_WAVE, fc, 1)
+ #self.src = gr.noise_source_c(gr.GR_GAUSSIAN, 1)
+ self.head = gr.head(gr.sizeof_gr_complex, N)
+
+ # A resampler with our taps
+ self.resamp_0 = filter.pfb.arb_resampler_ccf(rerate, taps,
+ flt_size=32)
+
+ # A resampler that just needs a resampling rate.
+ # Filter is created for us and designed to cover
+ # entire bandwidth of the input signal.
+ # An optional atten=XX rate can be used here to
+ # specify the out-of-band rejection (default=80).
+ self.resamp_1 = filter.pfb.arb_resampler_ccf(rerate)
+
+ self.snk_in = gr.vector_sink_c()
+ self.snk_0 = gr.vector_sink_c()
+ self.snk_1 = gr.vector_sink_c()
+
+ self.connect(self.src, self.head, self.snk_in)
+ self.connect(self.head, self.resamp_0, self.snk_0)
+ self.connect(self.head, self.resamp_1, self.snk_1)
+
+def main():
+ fs_in = 8000
+ fs_out = 20000
+ fc = 1000
+ N = 10000
+
+ tb = mytb(fs_in, fs_out, fc, N)
+ tb.run()
+
+
+ # Plot PSD of signals
+ nfftsize = 2048
+ fig1 = pylab.figure(1, figsize=(10,10), facecolor="w")
+ sp1 = fig1.add_subplot(2,1,1)
+ sp1.psd(tb.snk_in.data(), NFFT=nfftsize,
+ noverlap=nfftsize/4, Fs = fs_in)
+ sp1.set_title(("Input Signal at f_s=%.2f kHz" % (fs_in/1000.0)))
+ sp1.set_xlim([-fs_in/2, fs_in/2])
+
+ sp2 = fig1.add_subplot(2,1,2)
+ sp2.psd(tb.snk_0.data(), NFFT=nfftsize,
+ noverlap=nfftsize/4, Fs = fs_out,
+ label="With our filter")
+ sp2.psd(tb.snk_1.data(), NFFT=nfftsize,
+ noverlap=nfftsize/4, Fs = fs_out,
+ label="With auto-generated filter")
+ sp2.set_title(("Output Signals at f_s=%.2f kHz" % (fs_out/1000.0)))
+ sp2.set_xlim([-fs_out/2, fs_out/2])
+ sp2.legend()
+
+ # Plot signals in time
+ Ts_in = 1.0/fs_in
+ Ts_out = 1.0/fs_out
+ t_in = scipy.arange(0, len(tb.snk_in.data())*Ts_in, Ts_in)
+ t_out = scipy.arange(0, len(tb.snk_0.data())*Ts_out, Ts_out)
+
+ fig2 = pylab.figure(2, figsize=(10,10), facecolor="w")
+ sp21 = fig2.add_subplot(2,1,1)
+ sp21.plot(t_in, tb.snk_in.data())
+ sp21.set_title(("Input Signal at f_s=%.2f kHz" % (fs_in/1000.0)))
+ sp21.set_xlim([t_in[100], t_in[200]])
+
+ sp22 = fig2.add_subplot(2,1,2)
+ sp22.plot(t_out, tb.snk_0.data(),
+ label="With our filter")
+ sp22.plot(t_out, tb.snk_1.data(),
+ label="With auto-generated filter")
+ sp22.set_title(("Output Signals at f_s=%.2f kHz" % (fs_out/1000.0)))
+ r = float(fs_out)/float(fs_in)
+ sp22.set_xlim([t_out[r * 100], t_out[r * 200]])
+ sp22.legend()
+
+ pylab.show()
+
+if __name__ == "__main__":
+ main()
+
--
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