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Don Pearce[_3_] Don Pearce[_3_] is offline
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Default Class D power amplifier---what about class-D CD?

On Thu, 8 Oct 2009 05:11:34 -0700, "William Sommerwerck"
wrote:

When you say digital, do you mean store the data as a number,
as is done now, and feed it to a DAC, the output of which is a
pulse width rather than a voltage? If so, that could be done with
the CDs we have right now.


Here we go...

When I say "digital", I mean "quantized" -- there is only a finite number of
possible pulse widths.

This is doable right now, and in fact was done 30 years ago, with the
original LaserDisks, which used a form of analog pulse-width modulation.


OK, I get it. But why would the possible number of pulse widths be
finite (apart from quantum effects of course)? You can theoretically
make a pit any arbitrary length. Of course you would instantly be at
the mercy of scratches and dirt. Error correction would be a thing of
the past.

d