uPD1771C noise puzzle



LFSR feeding a delta-modulated logarithmic DAC???
Evil 80's reverse engineering protection???
Alien message?

Comments

  1. It looks like rising exponentials on the positive side, decaying exponentials on the negative side. Not that hard to create with digital logic, though probably time consuming to exactly recreate.

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  2. Hi

    Sure, but the precise steps heights and the distance between gap 'resets' is controlled by two or more clocks. This chip really needs decapping.

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  3. I took a crack at it. I think one clock can certainly get you something similar.
    http://8bc.org/forums/viewtopic.php?pid=327085#p327085

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