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#!/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, blks2
from gnuradio import filter
import sys, math, time
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)
class fmtx(gr.hier_block2):
def __init__(self, lo_freq, audio_rate, if_rate):
gr.hier_block2.__init__(self, "build_fm",
gr.io_signature(1, 1, gr.sizeof_float),
gr.io_signature(1, 1, gr.sizeof_gr_complex))
fmtx = blks2.nbfm_tx (audio_rate, if_rate, max_dev=5e3, tau=75e-6)
# Local oscillator
lo = gr.sig_source_c (if_rate, # sample rate
gr.GR_SIN_WAVE, # waveform type
lo_freq, #frequency
1.0, # amplitude
0) # DC Offset
mixer = gr.multiply_cc ()
self.connect (self, fmtx, (mixer, 0))
self.connect (lo, (mixer, 1))
self.connect (mixer, self)
class fmtest(gr.top_block):
def __init__(self):
gr.top_block.__init__(self)
self._nsamples = 1000000
self._audio_rate = 8000
# Set up N channels with their own baseband and IF frequencies
self._N = 5
chspacing = 16000
freq = [10, 20, 30, 40, 50]
f_lo = [0, 1*chspacing, -1*chspacing, 2*chspacing, -2*chspacing]
self._if_rate = 4*self._N*self._audio_rate
# Create a signal source and frequency modulate it
self.sum = gr.add_cc ()
for n in xrange(self._N):
sig = gr.sig_source_f(self._audio_rate, gr.GR_SIN_WAVE, freq[n], 0.5)
fm = fmtx(f_lo[n], self._audio_rate, self._if_rate)
self.connect(sig, fm)
self.connect(fm, (self.sum, n))
self.head = gr.head(gr.sizeof_gr_complex, self._nsamples)
self.snk_tx = gr.vector_sink_c()
self.channel = blks2.channel_model(0.1)
self.connect(self.sum, self.head, self.channel, self.snk_tx)
# Design the channlizer
self._M = 10
bw = chspacing/2.0
t_bw = chspacing/10.0
self._chan_rate = self._if_rate / self._M
self._taps = filter.firdes.low_pass_2(1, self._if_rate, bw, t_bw,
attenuation_dB=100,
window=filter.firdes.WIN_BLACKMAN_hARRIS)
tpc = math.ceil(float(len(self._taps)) / float(self._M))
print "Number of taps: ", len(self._taps)
print "Number of channels: ", self._M
print "Taps per channel: ", tpc
self.pfb = filter.pfb.channelizer_ccf(self._M, self._taps)
self.connect(self.channel, self.pfb)
# Create a file sink for each of M output channels of the filter and connect it
self.fmdet = list()
self.squelch = list()
self.snks = list()
for i in xrange(self._M):
self.fmdet.append(blks2.nbfm_rx(self._audio_rate, self._chan_rate))
self.squelch.append(blks2.standard_squelch(self._audio_rate*10))
self.snks.append(gr.vector_sink_f())
self.connect((self.pfb, i), self.fmdet[i], self.squelch[i], self.snks[i])
def num_tx_channels(self):
return self._N
def num_rx_channels(self):
return self._M
def main():
fm = fmtest()
tstart = time.time()
fm.run()
tend = time.time()
if 1:
fig1 = pylab.figure(1, figsize=(12,10), facecolor="w")
fig2 = pylab.figure(2, figsize=(12,10), facecolor="w")
fig3 = pylab.figure(3, figsize=(12,10), facecolor="w")
Ns = 10000
Ne = 100000
fftlen = 8192
winfunc = scipy.blackman
# Plot transmitted signal
fs = fm._if_rate
d = fm.snk_tx.data()[Ns:Ns+Ne]
sp1_f = fig1.add_subplot(2, 1, 1)
X,freq = sp1_f.psd(d, NFFT=fftlen, noverlap=fftlen/4, Fs=fs,
window = lambda d: d*winfunc(fftlen),
visible=False)
X_in = 10.0*scipy.log10(abs(fftpack.fftshift(X)))
f_in = scipy.arange(-fs/2.0, fs/2.0, fs/float(X_in.size))
p1_f = sp1_f.plot(f_in, X_in, "b")
sp1_f.set_xlim([min(f_in), max(f_in)+1])
sp1_f.set_ylim([-120.0, 20.0])
sp1_f.set_title("Input Signal", weight="bold")
sp1_f.set_xlabel("Frequency (Hz)")
sp1_f.set_ylabel("Power (dBW)")
Ts = 1.0/fs
Tmax = len(d)*Ts
t_in = scipy.arange(0, Tmax, Ts)
x_in = scipy.array(d)
sp1_t = fig1.add_subplot(2, 1, 2)
p1_t = sp1_t.plot(t_in, x_in.real, "b-o")
#p1_t = sp1_t.plot(t_in, x_in.imag, "r-o")
sp1_t.set_ylim([-5, 5])
# Set up the number of rows and columns for plotting the subfigures
Ncols = int(scipy.floor(scipy.sqrt(fm.num_rx_channels())))
Nrows = int(scipy.floor(fm.num_rx_channels() / Ncols))
if(fm.num_rx_channels() % Ncols != 0):
Nrows += 1
# Plot each of the channels outputs. Frequencies on Figure 2 and
# time signals on Figure 3
fs_o = fm._audio_rate
for i in xrange(len(fm.snks)):
# remove issues with the transients at the beginning
# also remove some corruption at the end of the stream
# this is a bug, probably due to the corner cases
d = fm.snks[i].data()[Ns:Ne]
sp2_f = fig2.add_subplot(Nrows, Ncols, 1+i)
X,freq = sp2_f.psd(d, NFFT=fftlen, noverlap=fftlen/4, Fs=fs_o,
window = lambda d: d*winfunc(fftlen),
visible=False)
#X_o = 10.0*scipy.log10(abs(fftpack.fftshift(X)))
X_o = 10.0*scipy.log10(abs(X))
#f_o = scipy.arange(-fs_o/2.0, fs_o/2.0, fs_o/float(X_o.size))
f_o = scipy.arange(0, fs_o/2.0, fs_o/2.0/float(X_o.size))
p2_f = sp2_f.plot(f_o, X_o, "b")
sp2_f.set_xlim([min(f_o), max(f_o)+0.1])
sp2_f.set_ylim([-120.0, 20.0])
sp2_f.grid(True)
sp2_f.set_title(("Channel %d" % i), weight="bold")
sp2_f.set_xlabel("Frequency (kHz)")
sp2_f.set_ylabel("Power (dBW)")
Ts = 1.0/fs_o
Tmax = len(d)*Ts
t_o = scipy.arange(0, Tmax, Ts)
x_t = scipy.array(d)
sp2_t = fig3.add_subplot(Nrows, Ncols, 1+i)
p2_t = sp2_t.plot(t_o, x_t.real, "b")
p2_t = sp2_t.plot(t_o, x_t.imag, "r")
sp2_t.set_xlim([min(t_o), max(t_o)+1])
sp2_t.set_ylim([-1, 1])
sp2_t.set_xlabel("Time (s)")
sp2_t.set_ylabel("Amplitude")
pylab.show()
if __name__ == "__main__":
main()
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