code: def mono_FM(x,fs=2.4e6,file_name='test.wav'):
      
      b = signal.firwin(64,2*200e3/float(fs))
      # Filter and decimate (should be polyphase)
      y = signal.lfilter(b,1,x)
      z = ss.downsample(y,10)
      # Apply complex baseband discriminator
      z_bb = discrim(z)
      # Design 2nd decimation lowpass filter (fc = 12 KHz)
      bb = signal.firwin(64,2*12e3/(float(fs)/10))
      # Filter and decimate
      zz_bb = signal.lfilter(bb,1,z_bb)
      # Decimate by 5
      z_out = ss.downsample(zz_bb,5)
      # Save to wave file
      ss.to_wav(file_name, 48000, z_out/2)
      print('Done!')
      return z_bb, z_out
docs: Decimate complex baseband input by 10
      Design 1st decimation lowpass filter (f_c = 200 KHz)