[vorbis] Copy protected CDs (off-topic)

[Dan Hollis]

On Wed, 20 Dec 2000, Gregory Maxwell wrote:
> You can see this drift on a CDR very easily: Create a CDR with pulses at a
> 1khz rate, hook a wideband scope to your cd player output and attach a high
> accuracy 1khz source (a desktop lab time source is useful here, a 1MHz out
> from a survey grade GPS into a down convery would probably work) to the
> trigger.
> Watch the pulse dance around.

Have you tried this with a test CD pressed from glass master also?

I think you will see the pulse dance around also. This is because even
on great CD players, the motor speed varies. So you've proven that gee, we
can see motor speed varying on a CD player! Wow!

Now, attach the oscilloscope to the DAC clock. That's a better test.

-Dan

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