Get a good microscope. All you see it pits, that's all the Laser sees.
A pit disperses the laser light so in that bit time there is no signal and
no pit reflects the light there is a signal. The signal in question is a 1
or a 0.



"Sidney Cadot" wrote in message
...
Hi all,

I am trying to gain an in-depth understanding of the digital encoding
used in compact discs, out of hobby interests. I think I got a grasp of
all the algorithms involved (CIRC encoding, EFM, and so on) but I would
like to verify my understanding by looking at the actual raw (analog)
signal as seen by the laser sensor in the CD's optical system.

For this purpose, it would be quite ideal to have access to a couple of
seconds worth of audio data as seen by the laser reflection pickup
sensor; something like 20 Msamples/sec at 8 bits/sample would be perfect
for me.

Would anybody know how I could get hold of this kind of data? I assume
that it is routinely produced by producers of CD hardware, but they will
probably not be keen to share :-)

Any pointers would be greatly appreciated.

Best regards,

Sidney Cadot
The Netherlands