Pseudorandom Noise Shift registers....

[The Old Crow]

  FWIW, a PIC (microcontroller) chip can be programmed with a feedback
shift register algorithm.  The chip runs fast enough to generate white
noise on a port pin.  (Using the 8-pin PIC12C508 configured to run from
its internal oscillator, You get a $1.50 digital noise generator that only
needs power).  I've also programmed PICs to do up to 13-note tone
generation.  Neat little chip.

  Have a look at the code at www.aeug.org/~chip/noise.asm

  --Scott

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