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I returned to DIY electronics in 2009 after a 20 year pause by building a few kits to get in shape. This blog is for me to keep track of my progress.
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Digital Audio Signal Generator

Posted 15th August 2010 at 01:50 PM by alexcp
Updated 15th August 2010 at 04:18 PM by alexcp

This handy instrument is a version of the design published in Australian Silicon Chip (a subscription is required to view the details of the article). It is based on a dsPIC33 microcontroller, has TOSLINK and S/PDIF digital outputs (44.1k, 48k and 96k sample rates) and a stereo analog output. Output frequency, phase, attenuation, and other parameters are set by the keyboard. It produces sine, square, triangle, and sawtooth waves and has a variety of modes. It can be powered by an external DC source or a battery. The article claims low distortion for sinewave (less than .06%) and even lower with a good external DAC, but I did not have a chance to verify that just yet. Highly recommended.
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Posted in Instrumentation
Views 3837 Comments 4
Total Comments 4


  1. Old Comment
    wintermute's Avatar
    nice is it available in kit form from Jaycar or DSE? I've been thinking about building something that does square waves, this might fit the bill nicely.

    Posted 16th August 2010 at 03:08 AM by wintermute wintermute is offline
  2. Old Comment
    alexcp's Avatar
    PCBs seem to available from RCS Radio, but I am not sure about kits - maybe it is easier for you to talk to Silicon Chip directly.

    Note that any sigma-delta DAC, including the dsPIC's internal DAC that this generator uses for analog output, produces square waves with some distortion (looks like ringing).
    Posted 16th August 2010 at 05:56 AM by alexcp alexcp is offline
  3. Old Comment
    wintermute's Avatar
    ok thanks for the heads up on the square wave ringing! Cheers,

    Posted 16th August 2010 at 08:23 AM by wintermute wintermute is offline
  4. Old Comment
    Posted 31st October 2010 at 04:42 PM by heinz1 heinz1 is offline

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