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fmtest.py
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#!/usr/bin/env python
#
# Copyright 2009,2012,2013 Free Software Foundation, Inc.
#
# This file is part of GNU Radio
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
#
from __future__ import print_function
from __future__ import division
from __future__ import unicode_literals
from gnuradio import gr
from gnuradio import blocks
from gnuradio import filter
from gnuradio import analog
from gnuradio import channels
import sys, math, time
import numpy
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 = analog.nbfm_tx(audio_rate, if_rate, max_dev=5e3,
tau=75e-6, fh=0.925*if_rate/2.0)
# Local oscillator
lo = analog.sig_source_c(if_rate, # sample rate
analog.GR_SIN_WAVE, # waveform type
lo_freq, # frequency
1.0, # amplitude
0) # DC Offset
mixer = blocks.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 = blocks.add_cc()
for n in range(self._N):
sig = analog.sig_source_f(self._audio_rate, analog.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 = blocks.head(gr.sizeof_gr_complex, self._nsamples)
self.snk_tx = blocks.vector_sink_c()
self.channel = channels.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 range(self._M):
self.fmdet.append(analog.nbfm_rx(self._audio_rate, self._chan_rate))
self.squelch.append(analog.standard_squelch(self._audio_rate*10))
self.snks.append(blocks.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 = numpy.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*numpy.log10(abs(numpy.fft.fftshift(X)))
f_in = numpy.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 = numpy.arange(0, Tmax, Ts)
x_in = numpy.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(numpy.floor(numpy.sqrt(fm.num_rx_channels())))
Nrows = int(numpy.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 range(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*numpy.log10(abs(numpy.fft.fftshift(X)))
X_o = 10.0*numpy.log10(abs(X))
#f_o = numpy.arange(-fs_o/2.0, fs_o/2.0, fs_o/float(X_o.size))
f_o = numpy.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 = numpy.arange(0, Tmax, Ts)
x_t = numpy.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()