PA1DSP - A simple RX script
      PA1DSP 


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            BasicDSP

            Fun with BasicDSP

            A simple RX script

            A PLL example

      A simple receiver script for BasicDSP
      The following script will receive LSB. By changing ‘audio = f2_out*cos1(y) 
      - f4_out*sin1(y)’ to ‘audio = f2_out*cos1(y) + f4_out*sin1(y)’, it will 
      receive USB.
      Slider1 controls the receive frequency, Slider2 controls the IF bandwidth 
      and Slider3 controls the volume. Be careful! The gain of this receiver is 
      high -- watch your ears! It has NO AGC!
      # set the samplerate to 48000 samples per second
      samplerate = 48000
      # down-convert to 1st IF:
      # z is a sawtooch oscillator
      # (ai,aq) form the mixer output
      # (ini, inq) are the soundcard's inputs
      z = mod1(z+slider1);
      ai = ini * cos1(z) - inq*sin1(z)
      aq = inq * cos1(z) + ini*sin1(z)
      # filter IF:
      # two RC-like filters, slider2 controls the bandwidth
      # I branch filter
      f1_out = f1_out - slider2*(f1_out - ai)
      f2_out = f2_out - slider2*(f2_out - f1_out)
      # Q branch filter
      f3_out = f3_out - slider2*(f3_out - aq)
      f4_out = f4_out - slider2*(f4_out - f3_out)
      # down-convert to audio using a second mixer
      y = mod1(y+0.0275)
      audio = f2_out*cos1(y) - f4_out*sin1(y)
      # send audio to output of soundcard
      # slider3 controls the volume
      uitL = audio * slider3 * 50
      uitR = audio * slider3 * 50
      A .WAV file containing SSB I/Q recordings you can use with BasicDSP can be 
      found on the Flex Radio website. Look under ‘Audio I/Q’.



       © 2006-2009  Niels Moseley     email: n.a.moseley at alumnus.utwente.nl