[sdiy] any ideas on how to do a quantizer with AVR?

[David Brown]

I didn't implement it with an AVR, but I did with my Basic 
Stamp.  The information is on my computervoltagesource page.
http://modularsynthesis.com/cvs/cvs.htm

You'll want a good DAC for the output.  I used a quad DAC interfaced 
via SPI to the processor.

Digitize the input, truncate it to the nearest semitone, and output 
it to the DAC.  Repeat in a loop.  Optionally, I added input 
hysteresis in software to avoid bouncing between semitones due to 
input noise.  It requires that the input voltage move 2~3 steps which 
is 2~3 mV in my system to recognize a change.  It's a small 
percentage of a semitone.

The trick was to make the DAC reference voltage 10.666 volts so that 
semitones are exactly on value every 32 steps.  This eliminates the 
additional digitization errors due to the DAC resolution.

Dave

At 12:38 PM 1/26/2011, dan snazelle wrote:
>I have found one pic project that uses assembler But so far I cant 
>find any  AVR or Arduino or C projects.
>
>I always figured a quantizer would be very easy to do with an AVR 
>but now I am not so sure.
>
>Does anyone have any ideas on how to implement it on a basic block level?
>
>thanks
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