#!/usr/bin/env python # # Copyright 2009,2012 Free Software Foundation, Inc. # # This file is part of GNU Radio # # GNU Radio is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 3, or (at your option) # any later version. # # GNU Radio is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with GNU Radio; see the file COPYING. If not, write to # the Free Software Foundation, Inc., 51 Franklin Street, # Boston, MA 02110-1301, USA. # from gnuradio import gr, blks2 from gnuradio import filter import sys, math, time try: import scipy from scipy import fftpack except ImportError: print "Error: Program requires scipy (see: www.scipy.org)." sys.exit(1) try: import pylab except ImportError: print "Error: Program requires matplotlib (see: matplotlib.sourceforge.net)." sys.exit(1) class fmtx(gr.hier_block2): def __init__(self, lo_freq, audio_rate, if_rate): gr.hier_block2.__init__(self, "build_fm", gr.io_signature(1, 1, gr.sizeof_float), gr.io_signature(1, 1, gr.sizeof_gr_complex)) fmtx = blks2.nbfm_tx (audio_rate, if_rate, max_dev=5e3, tau=75e-6) # Local oscillator lo = gr.sig_source_c (if_rate, # sample rate gr.GR_SIN_WAVE, # waveform type lo_freq, #frequency 1.0, # amplitude 0) # DC Offset mixer = gr.multiply_cc () self.connect (self, fmtx, (mixer, 0)) self.connect (lo, (mixer, 1)) self.connect (mixer, self) class fmtest(gr.top_block): def __init__(self): gr.top_block.__init__(self) self._nsamples = 1000000 self._audio_rate = 8000 # Set up N channels with their own baseband and IF frequencies self._N = 5 chspacing = 16000 freq = [10, 20, 30, 40, 50] f_lo = [0, 1*chspacing, -1*chspacing, 2*chspacing, -2*chspacing] self._if_rate = 4*self._N*self._audio_rate # Create a signal source and frequency modulate it self.sum = gr.add_cc () for n in xrange(self._N): sig = gr.sig_source_f(self._audio_rate, gr.GR_SIN_WAVE, freq[n], 0.5) fm = fmtx(f_lo[n], self._audio_rate, self._if_rate) self.connect(sig, fm) self.connect(fm, (self.sum, n)) self.head = gr.head(gr.sizeof_gr_complex, self._nsamples) self.snk_tx = gr.vector_sink_c() self.channel = blks2.channel_model(0.1) self.connect(self.sum, self.head, self.channel, self.snk_tx) # Design the channlizer self._M = 10 bw = chspacing/2.0 t_bw = chspacing/10.0 self._chan_rate = self._if_rate / self._M self._taps = filter.firdes.low_pass_2(1, self._if_rate, bw, t_bw, attenuation_dB=100, window=filter.firdes.WIN_BLACKMAN_hARRIS) tpc = math.ceil(float(len(self._taps)) / float(self._M)) print "Number of taps: ", len(self._taps) print "Number of channels: ", self._M print "Taps per channel: ", tpc self.pfb = filter.pfb.channelizer_ccf(self._M, self._taps) self.connect(self.channel, self.pfb) # Create a file sink for each of M output channels of the filter and connect it self.fmdet = list() self.squelch = list() self.snks = list() for i in xrange(self._M): self.fmdet.append(blks2.nbfm_rx(self._audio_rate, self._chan_rate)) self.squelch.append(blks2.standard_squelch(self._audio_rate*10)) self.snks.append(gr.vector_sink_f()) self.connect((self.pfb, i), self.fmdet[i], self.squelch[i], self.snks[i]) def num_tx_channels(self): return self._N def num_rx_channels(self): return self._M def main(): fm = fmtest() tstart = time.time() fm.run() tend = time.time() if 1: fig1 = pylab.figure(1, figsize=(12,10), facecolor="w") fig2 = pylab.figure(2, figsize=(12,10), facecolor="w") fig3 = pylab.figure(3, figsize=(12,10), facecolor="w") Ns = 10000 Ne = 100000 fftlen = 8192 winfunc = scipy.blackman # Plot transmitted signal fs = fm._if_rate d = fm.snk_tx.data()[Ns:Ns+Ne] sp1_f = fig1.add_subplot(2, 1, 1) X,freq = sp1_f.psd(d, NFFT=fftlen, noverlap=fftlen/4, Fs=fs, window = lambda d: d*winfunc(fftlen), visible=False) X_in = 10.0*scipy.log10(abs(fftpack.fftshift(X))) f_in = scipy.arange(-fs/2.0, fs/2.0, fs/float(X_in.size)) p1_f = sp1_f.plot(f_in, X_in, "b") sp1_f.set_xlim([min(f_in), max(f_in)+1]) sp1_f.set_ylim([-120.0, 20.0]) sp1_f.set_title("Input Signal", weight="bold") sp1_f.set_xlabel("Frequency (Hz)") sp1_f.set_ylabel("Power (dBW)") Ts = 1.0/fs Tmax = len(d)*Ts t_in = scipy.arange(0, Tmax, Ts) x_in = scipy.array(d) sp1_t = fig1.add_subplot(2, 1, 2) p1_t = sp1_t.plot(t_in, x_in.real, "b-o") #p1_t = sp1_t.plot(t_in, x_in.imag, "r-o") sp1_t.set_ylim([-5, 5]) # Set up the number of rows and columns for plotting the subfigures Ncols = int(scipy.floor(scipy.sqrt(fm.num_rx_channels()))) Nrows = int(scipy.floor(fm.num_rx_channels() / Ncols)) if(fm.num_rx_channels() % Ncols != 0): Nrows += 1 # Plot each of the channels outputs. Frequencies on Figure 2 and # time signals on Figure 3 fs_o = fm._audio_rate for i in xrange(len(fm.snks)): # remove issues with the transients at the beginning # also remove some corruption at the end of the stream # this is a bug, probably due to the corner cases d = fm.snks[i].data()[Ns:Ne] sp2_f = fig2.add_subplot(Nrows, Ncols, 1+i) X,freq = sp2_f.psd(d, NFFT=fftlen, noverlap=fftlen/4, Fs=fs_o, window = lambda d: d*winfunc(fftlen), visible=False) #X_o = 10.0*scipy.log10(abs(fftpack.fftshift(X))) X_o = 10.0*scipy.log10(abs(X)) #f_o = scipy.arange(-fs_o/2.0, fs_o/2.0, fs_o/float(X_o.size)) f_o = scipy.arange(0, fs_o/2.0, fs_o/2.0/float(X_o.size)) p2_f = sp2_f.plot(f_o, X_o, "b") sp2_f.set_xlim([min(f_o), max(f_o)+0.1]) sp2_f.set_ylim([-120.0, 20.0]) sp2_f.grid(True) sp2_f.set_title(("Channel %d" % i), weight="bold") sp2_f.set_xlabel("Frequency (kHz)") sp2_f.set_ylabel("Power (dBW)") Ts = 1.0/fs_o Tmax = len(d)*Ts t_o = scipy.arange(0, Tmax, Ts) x_t = scipy.array(d) sp2_t = fig3.add_subplot(Nrows, Ncols, 1+i) p2_t = sp2_t.plot(t_o, x_t.real, "b") p2_t = sp2_t.plot(t_o, x_t.imag, "r") sp2_t.set_xlim([min(t_o), max(t_o)+1]) sp2_t.set_ylim([-1, 1]) sp2_t.set_xlabel("Time (s)") sp2_t.set_ylabel("Amplitude") pylab.show() if __name__ == "__main__": main()