#!/usr/bin/env python
#
# Copyright 2011-2013 Free Software Foundation, Inc.
#
# This file is part of GNU Radio
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
#
from gnuradio import gr, digital, filter
from gnuradio import blocks
from gnuradio import channels
from gnuradio import eng_notation
from gnuradio.eng_arg import eng_float, intx
from argparse import ArgumentParser
import sys
import numpy
try:
from matplotlib import pyplot
except ImportError:
print("Error: could not from matplotlib import pyplot (http://matplotlib.sourceforge.net/)")
sys.exit(1)
class example_timing(gr.top_block):
def __init__(self, N, sps, rolloff, ntaps, bw, noise,
foffset, toffset, poffset, mode=0):
gr.top_block.__init__(self)
rrc_taps = filter.firdes.root_raised_cosine(
sps, sps, 1.0, rolloff, ntaps)
gain = bw
nfilts = 32
rrc_taps_rx = filter.firdes.root_raised_cosine(
nfilts, sps * nfilts, 1.0, rolloff, ntaps * nfilts)
data = 2.0 * numpy.random.randint(0, 2, N) - 1.0
data = numpy.exp(1j * poffset) * data
self.src = blocks.vector_source_c(data.tolist(), False)
self.rrc = filter.interp_fir_filter_ccf(sps, rrc_taps)
self.chn = channels.channel_model(noise, foffset, toffset)
self.off = filter.mmse_resampler_cc(0.20, 1.0)
if mode == 0:
self.clk = digital.pfb_clock_sync_ccf(sps, gain, rrc_taps_rx,
nfilts, nfilts // 2, 1)
self.taps = self.clk.taps()
self.dtaps = self.clk.diff_taps()
self.delay = int(numpy.ceil(((len(rrc_taps) - 1) // 2 +
(len(self.taps[0]) - 1) // 2) // float(sps))) + 1
self.vsnk_err = blocks.vector_sink_f()
self.vsnk_rat = blocks.vector_sink_f()
self.vsnk_phs = blocks.vector_sink_f()
self.connect((self.clk, 1), self.vsnk_err)
self.connect((self.clk, 2), self.vsnk_rat)
self.connect((self.clk, 3), self.vsnk_phs)
else: # mode == 1
mu = 0.5
gain_mu = bw
gain_omega = 0.25 * gain_mu * gain_mu
omega_rel_lim = 0.02
self.clk = digital.clock_recovery_mm_cc(sps, gain_omega,
mu, gain_mu,
omega_rel_lim)
self.vsnk_err = blocks.vector_sink_f()
self.connect((self.clk, 1), self.vsnk_err)
self.vsnk_src = blocks.vector_sink_c()
self.vsnk_clk = blocks.vector_sink_c()
self.connect(self.src, self.rrc, self.chn,
self.off, self.clk, self.vsnk_clk)
self.connect(self.src, self.vsnk_src)
def main():
parser = ArgumentParser(conflict_handler="resolve")
parser.add_argument("-N", "--nsamples", type=int, default=2000,
help="Set the number of samples to process [default=%(default)r]")
parser.add_argument("-S", "--sps", type=int, default=4,
help="Set the samples per symbol [default=%(default)r]")
parser.add_argument("-r", "--rolloff", type=eng_float, default=0.35,
help="Set the rolloff factor [default=%(default)r]")
parser.add_argument("-W", "--bandwidth", type=eng_float, default=2 * numpy.pi / 100.0,
help="Set the loop bandwidth (PFB) or gain (M&M) [default=%(default)r]")
parser.add_argument("-n", "--ntaps", type=int, default=45,
help="Set the number of taps in the filters [default=%(default)r]")
parser.add_argument("--noise", type=eng_float, default=0.0,
help="Set the simulation noise voltage [default=%(default)r]")
parser.add_argument("-f", "--foffset", type=eng_float, default=0.0,
help="Set the simulation's normalized frequency offset (in Hz) [default=%(default)r]")
parser.add_argument("-t", "--toffset", type=eng_float, default=1.0,
help="Set the simulation's timing offset [default=%(default)r]")
parser.add_argument("-p", "--poffset", type=eng_float, default=0.0,
help="Set the simulation's phase offset [default=%(default)r]")
parser.add_argument("-M", "--mode", type=int, default=0,
help="Set the recovery mode (0: polyphase, 1: M&M) [default=%(default)r]")
args = parser.parse_args()
# Adjust N for the interpolation by sps
args.nsamples = args.nsamples // args.sps
# Set up the program-under-test
put = example_timing(args.nsamples, args.sps, args.rolloff,
args.ntaps, args.bandwidth, args.noise,
args.foffset, args.toffset, args.poffset,
args.mode)
put.run()
if args.mode == 0:
data_src = numpy.array(put.vsnk_src.data()[20:])
data_clk = numpy.array(put.vsnk_clk.data()[20:])
data_err = numpy.array(put.vsnk_err.data()[20:])
data_rat = numpy.array(put.vsnk_rat.data()[20:])
data_phs = numpy.array(put.vsnk_phs.data()[20:])
f1 = pyplot.figure(1, figsize=(12, 10), facecolor='w')
# Plot the IQ symbols
s1 = f1.add_subplot(2, 2, 1)
s1.plot(data_src.real, data_src.imag, "bo")
s1.plot(data_clk.real, data_clk.imag, "ro")
s1.set_title("IQ")
s1.set_xlabel("Real part")
s1.set_ylabel("Imag part")
s1.set_xlim([-2, 2])
s1.set_ylim([-2, 2])
# Plot the symbols in time
delay = put.delay
m = len(data_clk.real)
s2 = f1.add_subplot(2, 2, 2)
s2.plot(data_src.real, "bs", markersize=10, label="Input")
s2.plot(data_clk.real[delay:], "ro", label="Recovered")
s2.set_title("Symbols")
s2.set_xlabel("Samples")
s2.set_ylabel("Real Part of Signals")
s2.legend()
# Plot the clock recovery loop's error
s3 = f1.add_subplot(2, 2, 3)
s3.plot(data_err, label="Error")
s3.plot(data_rat, 'r', label="Update rate")
s3.set_title("Clock Recovery Loop Error")
s3.set_xlabel("Samples")
s3.set_ylabel("Error")
s3.set_ylim([-0.5, 0.5])
s3.legend()
# Plot the clock recovery loop's error
s4 = f1.add_subplot(2, 2, 4)
s4.plot(data_phs)
s4.set_title("Clock Recovery Loop Filter Phase")
s4.set_xlabel("Samples")
s4.set_ylabel("Filter Phase")
diff_taps = put.dtaps
ntaps = len(diff_taps[0])
nfilts = len(diff_taps)
t = numpy.arange(0, ntaps * nfilts)
f3 = pyplot.figure(3, figsize=(12, 10), facecolor='w')
s31 = f3.add_subplot(2, 1, 1)
s32 = f3.add_subplot(2, 1, 2)
s31.set_title("Differential Filters")
s32.set_title("FFT of Differential Filters")
for i, d in enumerate(diff_taps):
D = 20.0 * \
numpy.log10(
1e-20 + abs(numpy.fft.fftshift(numpy.fft.fft(d, 10000))))
s31.plot(t[i::nfilts].real, d, "-o")
s32.plot(D)
s32.set_ylim([-120, 10])
# If testing the M&M clock recovery loop
else:
data_src = numpy.array(put.vsnk_src.data()[20:])
data_clk = numpy.array(put.vsnk_clk.data()[20:])
data_err = numpy.array(put.vsnk_err.data()[20:])
f1 = pyplot.figure(1, figsize=(12, 10), facecolor='w')
# Plot the IQ symbols
s1 = f1.add_subplot(2, 2, 1)
s1.plot(data_src.real, data_src.imag, "o")
s1.plot(data_clk.real, data_clk.imag, "ro")
s1.set_title("IQ")
s1.set_xlabel("Real part")
s1.set_ylabel("Imag part")
s1.set_xlim([-2, 2])
s1.set_ylim([-2, 2])
# Plot the symbols in time
s2 = f1.add_subplot(2, 2, 2)
s2.plot(data_src.real, "bs", markersize=10, label="Input")
s2.plot(data_clk.real, "ro", label="Recovered")
s2.set_title("Symbols")
s2.set_xlabel("Samples")
s2.set_ylabel("Real Part of Signals")
s2.legend()
# Plot the clock recovery loop's error
s3 = f1.add_subplot(2, 2, 3)
s3.plot(data_err)
s3.set_title("Clock Recovery Loop Error")
s3.set_xlabel("Samples")
s3.set_ylabel("Error")
pyplot.show()
if __name__ == "__main__":
try:
main()
except KeyboardInterrupt:
pass