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#!/usr/bin/env python
#
# Copyright 2010,2012,2013 Free Software Foundation, Inc.
#
# This file is part of GNU Radio
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
#
from gnuradio import gr, digital
from gnuradio import filter
from gnuradio import blocks
from gnuradio.fft import window
import sys
import numpy
try:
from gnuradio import channels
except ImportError:
print("Error: Program requires gr-channels.")
sys.exit(1)
try:
from matplotlib import pyplot
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 = numpy.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,
window.WIN_BLACKMAN_hARRIS)
print("Filter length: ", len(proto_taps))
# Create a modulated signal
npwr = 0.01
data = numpy.random.randint(0, 256, N)
rrc_taps = filter.firdes.root_raised_cosine(1, 2, 1, 0.35, 41)
src = blocks.vector_source_b(data.astype(numpy.uint8).tolist(), False)
mod = digital.psk_mod(samples_per_symbol=2)
chan = channels.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 = blocks.vector_sink_c()
snk = blocks.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 range(nchans):
tb.connect((channelizer, i), (synthesizer, i))
vsnk.append(blocks.vector_sink_c())
tb.connect((channelizer, i), vsnk[i])
tb.connect(synthesizer, snk)
tb.run()
sin = numpy.array(src_snk.data()[1000:])
sout = numpy.array(snk.data()[1000:])
# Plot original signal
fs_in = nchans * fs
f1 = pyplot.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 = 2
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(numpy.sqrt(nchans))
ncols = int(numpy.ceil(float(nchans) / float(nrows)))
f2 = pyplot.figure(2, figsize=(16, 12), facecolor='w')
for n in range(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 = pyplot.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 = 0
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])
pyplot.show()
if __name__ == "__main__":
try:
main()
except KeyboardInterrupt:
pass
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