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#!/usr/bin/env python
#
# Copyright 2009,2010,2012 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, optfir
import filter_swig as filter
class channelizer_ccf(gr.hier_block2):
'''
Make a Polyphase Filter channelizer (complex in, complex out, floating-point taps)
This simplifies the interface by allowing a single input stream to connect to this block.
It will then output a stream for each channel.
'''
def __init__(self, numchans, taps=None, oversample_rate=1, atten=100):
gr.hier_block2.__init__(self, "pfb_channelizer_ccf",
gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
gr.io_signature(numchans, numchans, gr.sizeof_gr_complex)) # Output signature
self._nchans = numchans
self._oversample_rate = oversample_rate
if taps is not None:
self._taps = taps
else:
# Create a filter that covers the full bandwidth of the input signal
bw = 0.4
tb = 0.2
ripple = 0.1
made = False
while not made:
try:
self._taps = optfir.low_pass(1, self._nchans, bw, bw+tb, ripple, atten)
made = True
except RuntimeError:
ripple += 0.01
made = False
print("Warning: set ripple to %.4f dB. If this is a problem, adjust the attenuation or create your own filter taps." % (ripple))
# Build in an exit strategy; if we've come this far, it ain't working.
if(ripple >= 1.0):
raise RuntimeError("optfir could not generate an appropriate filter.")
self.s2ss = gr.stream_to_streams(gr.sizeof_gr_complex, self._nchans)
self.pfb = filter.pfb_channelizer_ccf(self._nchans, self._taps,
self._oversample_rate)
self.connect(self, self.s2ss)
for i in xrange(self._nchans):
self.connect((self.s2ss,i), (self.pfb,i))
self.connect((self.pfb,i), (self,i))
def set_channel_map(self, newmap):
self.pfb.set_channel_map(newmap)
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