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584Firmware update

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  • scott@opentrac.org
    Jun 2, 2006
      Ok, latest version is posted. I dug up a revised version of the FSK
      modulator I wrote for the OpenTracker around the end of 2004. It never
      worked right and I gave up on it at the time, but I took another look at it
      and found two bugs - an overlooked flag, and an improperly generated sine
      table. Fixed those and it's working great now.

      The new code expands the PWM output to 7 bits resolution from 4. This
      should produce slightly cleaner audio, but it also provides some extra room
      for scaling.

      The TXLEVEL command is now implemented, and will scale the audio level over
      a fairly wide range. I wouldn't take it below about 32 though, or
      quantization noise might start being a problem.

      I'll have to see if I've got a radio around here that requires a high audio
      drive level, and see if I can get the tracker to work on both that and a
      regular radio with the same hardware setup. At the very least, I'll hook it
      up to a real 'scope tomorrow and see what I can get for usable voltage
      ranges.

      Scott
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