content: #!/usr/bin/env python
  #
  # Copyright 2009 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
  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),      # Input signature
                                  gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature
  
          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 = gr.firdes.low_pass_2(1, self._if_rate, bw, t_bw,
                                            attenuation_dB=100,
                                            window=gr.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 = blks2.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()
  