From 5640f0e1a70b7af2d26f03e886cab447a18d2cc5 Mon Sep 17 00:00:00 2001 From: max Date: Tue, 29 May 2012 15:17:27 +0000 Subject: [PATCH] add tone detect option git-svn-id: http://op25.osmocom.org/svn/trunk@299 65a5c917-d112-43f1-993d-58c26a4786be --- python/cqpsk-demod-file.py | 40 +++++++++++++++++++++++--------------- 1 file changed, 24 insertions(+), 16 deletions(-) diff --git a/python/cqpsk-demod-file.py b/python/cqpsk-demod-file.py index 529ade3..2cc6e8a 100755 --- a/python/cqpsk-demod-file.py +++ b/python/cqpsk-demod-file.py @@ -34,10 +34,11 @@ class my_top_block(gr.top_block): 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=12.5e3, help="low pass cut-off", metavar="Hz") + 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("-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") (options, args) = parser.parse_args() @@ -61,20 +62,27 @@ class my_top_block(gr.top_block): lpf_taps = gr.firdes.low_pass(1.0, sample_rate, options.low_pass, options.low_pass * 0.1, gr.firdes.WIN_HANN) - # decim by 2 to get 48k rate - DECIM = gr.fir_filter_ccf (2, lpf_taps) - sample_rate /= 2 # for DECIM - samples_per_symbol /= 2 # for DECIM - - # 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 - GARDNER_COSTAS = repeater.gardner_costas_cc(samples_per_symbol, timing_error_gain, gain_omega, alpha, beta, fmax, fmin) + decim_amt = 1 + if options.tone_detect: + 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 @@ -117,7 +125,7 @@ class my_top_block(gr.top_block): else: self.connect(IN, (MIXER, 0)) self.connect(LO, (MIXER, 1)) - self.connect(MIXER, AMP, DECIM, GARDNER_COSTAS, DIFF, TOFLOAT, RESCALE, POLARITY, SLICER, DECODER, OUT) + self.connect(MIXER, AMP, DECIM, DEMOD, DIFF, TOFLOAT, RESCALE, POLARITY, SLICER, DECODER, OUT) if options.debug: print 'Ready for GDB to attach (pid = %d)' % (os.getpid(),)