154 lines
6.4 KiB
Python
Executable File
154 lines
6.4 KiB
Python
Executable File
#!/usr/bin/env python
|
|
|
|
#
|
|
# (C) Copyright 2010 KA1RBI
|
|
#
|
|
# apply CQPSK demodulator and P25 decoder to a sample capture file.
|
|
#
|
|
# input file is a sampled complex signal, default rate=96k
|
|
#
|
|
# Example usage:
|
|
# cqpsk-demod-file.py -i samples/trunk-control-complex-96KSS.dat -c 25300 -g 22
|
|
#
|
|
# FIXME: many of the blocks in this program should be moved to a hier block
|
|
#
|
|
|
|
import sys
|
|
import os
|
|
import math
|
|
from gnuradio import gr, gru, audio, eng_notation, repeater
|
|
from gnuradio.eng_option import eng_option
|
|
from optparse import OptionParser
|
|
|
|
from math import pi
|
|
|
|
class my_top_block(gr.top_block):
|
|
def __init__(self):
|
|
gr.top_block.__init__(self)
|
|
parser = OptionParser(option_class=eng_option)
|
|
|
|
parser.add_option("-1", "--one-channel", action="store_true", default=False, help="software synthesized Q channel")
|
|
parser.add_option("-a", "--agc", action="store_true", default=False, help="automatic gain control (overrides --gain)")
|
|
parser.add_option("-c", "--calibration", type="eng_float", default=0, help="freq offset")
|
|
parser.add_option("-d", "--debug", action="store_true", default=False, help="allow time at init to attach gdb")
|
|
parser.add_option("-C", "--costas-alpha", type="eng_float", default=0.125, help="Costas alpha")
|
|
parser.add_option("-g", "--gain", type="eng_float", default=1.0)
|
|
parser.add_option("-i", "--input-file", type="string", default="in.dat", help="specify the input file")
|
|
parser.add_option("-I", "--imbe", action="store_true", default=False, help="output IMBE codewords")
|
|
parser.add_option("-L", "--low-pass", type="eng_float", default=6.5e3, help="low pass cut-off", metavar="Hz")
|
|
parser.add_option("-o", "--output-file", type="string", default="out.dat", help="specify the output file")
|
|
parser.add_option("-p", "--polarity", action="store_true", default=False, help="use reversed polarity")
|
|
parser.add_option("-r", "--raw-symbols", type="string", default=None, help="dump decoded symbols to file")
|
|
parser.add_option("-s", "--sample-rate", type="int", default=96000, help="input sample rate")
|
|
parser.add_option("-t", "--tone-detect", action="store_true", default=False, help="use experimental tone detect algorithm")
|
|
parser.add_option("-v", "--verbose", action="store_true", default=False, help="additional output")
|
|
parser.add_option("-6", "--k6k", action="store_true", default=False, help="use 6K symbol rate")
|
|
(options, args) = parser.parse_args()
|
|
|
|
sample_rate = options.sample_rate
|
|
if options.k6k:
|
|
symbol_rate = 6000
|
|
else:
|
|
symbol_rate = 4800
|
|
samples_per_symbol = sample_rate // symbol_rate
|
|
|
|
IN = gr.file_source(gr.sizeof_gr_complex, options.input_file)
|
|
|
|
if options.one_channel:
|
|
C2F = gr.complex_to_float()
|
|
F2C = gr.float_to_complex()
|
|
|
|
# osc./mixer for mixing signal down to approx. zero IF
|
|
LO = gr.sig_source_c (sample_rate, gr.GR_COS_WAVE, options.calibration, 1.0, 0)
|
|
MIXER = gr.multiply_cc()
|
|
|
|
# get signal into normalized range (-1.0 - +1.0)
|
|
if options.agc:
|
|
AMP = gr.feedforward_agc_cc(16, 1.0)
|
|
else:
|
|
AMP = gr.multiply_const_cc(options.gain)
|
|
|
|
lpf_taps = gr.firdes.low_pass(1.0, sample_rate, options.low_pass, options.low_pass * 0.1, gr.firdes.WIN_HANN)
|
|
|
|
decim_amt = 1
|
|
if options.tone_detect:
|
|
if sample_rate != 96000:
|
|
print "warning, only 96K has been tested."
|
|
print "other rates may require theta to be reviewed/adjusted."
|
|
step_size = 7.5e-8
|
|
theta = -4 # optimum timing sampling point
|
|
cic_length = 48
|
|
DEMOD = repeater.tdetect_cc(samples_per_symbol, step_size, theta, cic_length)
|
|
else:
|
|
# decim by 2 to get 48k rate
|
|
samples_per_symbol /= 2 # for DECIM
|
|
sample_rate /= 2 # for DECIM
|
|
decim_amt = 2
|
|
# create Gardner/Costas loop
|
|
# the loop will not work if the sample levels aren't normalized (above)
|
|
timing_error_gain = 0.025 # loop error gain
|
|
gain_omega = 0.25 * timing_error_gain * timing_error_gain
|
|
alpha = options.costas_alpha
|
|
beta = 0.125 * alpha * alpha
|
|
fmin = -0.025 # fmin and fmax are in radians/s
|
|
fmax = 0.025
|
|
DEMOD = repeater.gardner_costas_cc(samples_per_symbol, timing_error_gain, gain_omega, alpha, beta, fmax, fmin)
|
|
DECIM = gr.fir_filter_ccf (decim_amt, lpf_taps)
|
|
|
|
# probably too much phase noise etc to attempt coherent demodulation
|
|
# so we use differential
|
|
DIFF = gr.diff_phasor_cc()
|
|
|
|
# take angle of the phase difference (in radians)
|
|
TOFLOAT = gr.complex_to_arg()
|
|
|
|
# convert from radians such that signal is in [-3, -1, +1, +3]
|
|
RESCALE = gr.multiply_const_ff(1 / (pi / 4.0))
|
|
|
|
# optional polarity reversal (should be unnec. - now autodetected)
|
|
p = 1.0
|
|
if options.polarity:
|
|
p = -1.0
|
|
POLARITY = gr.multiply_const_ff(p)
|
|
|
|
# hard decision at specified points
|
|
levels = [-2.0, 0.0, 2.0, 4.0 ]
|
|
SLICER = repeater.fsk4_slicer_fb(levels)
|
|
|
|
# assemble received frames and route to Wireshark via UDP
|
|
hostname = "127.0.0.1"
|
|
port = 23456
|
|
debug = 0
|
|
if options.verbose:
|
|
debug = 255
|
|
do_imbe = False
|
|
if options.imbe:
|
|
do_imbe = True
|
|
do_output = True # enable block's output stream
|
|
do_msgq = False # msgq output not yet implemented
|
|
msgq = gr.msg_queue(2)
|
|
DECODER = repeater.p25_frame_assembler(hostname, port, debug, do_imbe, do_output, do_msgq, msgq)
|
|
|
|
OUT = gr.file_sink(gr.sizeof_char, options.output_file)
|
|
|
|
if options.one_channel:
|
|
self.connect(IN, C2F, F2C, (MIXER, 0))
|
|
else:
|
|
self.connect(IN, (MIXER, 0))
|
|
self.connect(LO, (MIXER, 1))
|
|
self.connect(MIXER, AMP, DECIM, DEMOD, DIFF, TOFLOAT, RESCALE, POLARITY, SLICER, DECODER, OUT)
|
|
|
|
if options.raw_symbols:
|
|
SINKC = gr.file_sink(gr.sizeof_char, options.raw_symbols)
|
|
self.connect(SLICER, SINKC)
|
|
|
|
if options.debug:
|
|
print 'Ready for GDB to attach (pid = %d)' % (os.getpid(),)
|
|
raw_input("Press 'Enter' to continue...")
|
|
|
|
if __name__ == "__main__":
|
|
try:
|
|
my_top_block().run()
|
|
except KeyboardInterrupt:
|
|
tb.stop()
|