diff options
Diffstat (limited to 'gr-digital')
| -rwxr-xr-x | gr-digital/examples/example_timing.py | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/gr-digital/examples/example_timing.py b/gr-digital/examples/example_timing.py new file mode 100755 index 000000000..5e4d6edf7 --- /dev/null +++ b/gr-digital/examples/example_timing.py @@ -0,0 +1,157 @@ +#!/usr/bin/env python + +from gnuradio import gr, digital +from gnuradio import eng_notation +from gnuradio.eng_option import eng_option +from optparse import OptionParser + +try: + import scipy +except ImportError: + print "Error: could not import scipy (http://www.scipy.org/)" + sys.exit(1) + +try: + import pylab +except ImportError: + print "Error: could not import pylab (http://matplotlib.sourceforge.net/)" + sys.exit(1) + +from scipy import fftpack + +class example_timing(gr.top_block): + def __init__(self, N, sps, rolloff, ntaps, bw, noise, foffset, toffset, poffset): + gr.top_block.__init__(self) + + rrc_taps = gr.firdes.root_raised_cosine( + sps, sps, 1.0, rolloff, ntaps) + + gain = scipy.pi/100.0 + nfilts = 32 + rrc_taps_rx = gr.firdes.root_raised_cosine( + nfilts, sps*nfilts, 1.0, rolloff, ntaps*nfilts) + + data = 2.0*scipy.random.randint(0, 2, N) - 1.0 + data = scipy.exp(1j*poffset) * data + + self.src = gr.vector_source_c(data.tolist(), False) + self.rrc = gr.interp_fir_filter_ccf(sps, rrc_taps) + self.chn = gr.channel_model(noise, foffset, toffset) + self.off = gr.fractional_interpolator_cc(0.20, 1.0) + self.clk = gr.pfb_clock_sync_ccf(sps, gain, rrc_taps_rx, + nfilts, nfilts/2, 3.5) + + self.taps = self.clk.get_taps() + self.dtaps = self.clk.get_diff_taps() + + self.vsnk_src = gr.vector_sink_c() + self.vsnk_clk = gr.vector_sink_c() + self.vsnk_err = gr.vector_sink_f() + self.vsnk_rat = gr.vector_sink_f() + self.vsnk_phs = gr.vector_sink_f() + + self.connect(self.src, self.rrc, self.chn, self.off, self.clk, self.vsnk_clk) + self.connect(self.off, self.vsnk_src) + self.connect((self.clk,1), self.vsnk_err) + self.connect((self.clk,2), self.vsnk_rat) + self.connect((self.clk,3), self.vsnk_phs) + + +def main(): + parser = OptionParser(option_class=eng_option, conflict_handler="resolve") + parser.add_option("-N", "--nsamples", type="int", default=2000, + help="Set the number of samples to process [default=%default]") + parser.add_option("-S", "--sps", type="int", default=4, + help="Set the samples per symbol [default=%default]") + parser.add_option("-r", "--rolloff", type="eng_float", default=0.35, + help="Set the rolloff factor [default=%default]") + parser.add_option("-W", "--bandwidth", type="eng_float", default=2*scipy.pi/100.0, + help="Set the loop bandwidth [default=%default]") + parser.add_option("-n", "--ntaps", type="int", default=45, + help="Set the number of taps in the filters [default=%default]") + parser.add_option("", "--noise", type="eng_float", default=0.0, + help="Set the simulation noise voltage [default=%default]") + parser.add_option("-f", "--foffset", type="eng_float", default=0.0, + help="Set the simulation's normalized frequency offset (in Hz) [default=%default]") + parser.add_option("-t", "--toffset", type="eng_float", default=1.0, + help="Set the simulation's timing offset [default=%default]") + parser.add_option("-p", "--poffset", type="eng_float", default=0.0, + help="Set the simulation's phase offset [default=%default]") + (options, args) = parser.parse_args () + + # Adjust N for the interpolation by sps + options.nsamples = options.nsamples // options.sps + + # Set up the program-under-test + put = example_timing(options.nsamples, options.sps, options.rolloff, + options.ntaps, options.bandwidth, options.noise, + options.foffset, options.toffset, options.poffset) + put.run() + + data_src = scipy.array(put.vsnk_src.data()[20:]) + data_clk = scipy.array(put.vsnk_clk.data()[20:]) + + data_err = scipy.array(put.vsnk_err.data()[20:]) + data_rat = scipy.array(put.vsnk_rat.data()[20:]) + data_phs = scipy.array(put.vsnk_phs.data()[20:]) + + # Plot the clock recovery loop's error + f1 = pylab.figure(1, figsize=(12,10), facecolor='w') + s1 = f1.add_subplot(2,2,1) + s1.plot(data_err) + #s1.plot(data_rat, 'r') + s1.set_title("Clock Recovery Loop Error") + s1.set_xlabel("Samples") + s1.set_ylabel("Error") + + # Plot the clock recovery loop's error + f1 = pylab.figure(1, figsize=(12,10), facecolor='w') + s2 = f1.add_subplot(2,2,2) + s2.plot(data_phs) + s2.set_title("Clock Recovery Loop Filter Phase") + s2.set_xlabel("Samples") + s2.set_ylabel("Filter Phase") + + # Plot the IQ symbols + s3 = f1.add_subplot(2,2,3) + s3.plot(data_src.real, data_src.imag, "o") + s3.plot(data_clk.real, data_clk.imag, "rx") + s3.set_title("IQ") + s3.set_xlabel("Real part") + s3.set_ylabel("Imag part") + s3.set_xlim([-2, 2]) + s3.set_ylim([-2, 2]) + + # Plot the symbols in time + s4 = f1.add_subplot(2,2,4) + s4.plot(data_src.real, "o-") + s4.plot(data_clk.real, "rx-") + s4.set_title("Symbols") + s4.set_xlabel("Samples") + s4.set_ylabel("Real Part of Signals") + + + diff_taps = put.dtaps + ntaps = len(diff_taps[0]) + nfilts = len(diff_taps) + t = scipy.arange(0, ntaps*nfilts) + + f3 = pylab.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*scipy.log10(abs(fftpack.fftshift(fftpack.fft(d, 10000)))) + s31.plot(t[i::nfilts].real, d, "-o") + s32.plot(D) + + pylab.show() + +if __name__ == "__main__": + try: + main() + except KeyboardInterrupt: + pass + |