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What is CD Quality?
A high quality Compact Disc is one that will play in every drive, every
time, with performance and lifetime appropriate to the application.
How can I measure CD Quality?
Because the Compact Disc format is standardized, you can ensure the quality
of a CD by making sure that all parameters are well within the specification.
The specification for all CD's is the so-called "Red Book".
Any disc made to this spec should play in every drive every time, and
have a long lifetime.
Unfortunately, the Red Book specifies more than 50 different parameters.
To measure each of these would require a million dollars worth of test
equipment and a PhD to run it! The good news is that there are things
you can do at a modest cost that will greatly increase the probability
of making high quality discs.
There are two elements to measuring disc quality: Error rates and pit
geometry.
Error measurements
The easiest way to get a picture of disc quality is to measure error rates.
Most serious defects will cause an increase in error rates. By looking
at both the quantity and severity of errors, you can get a pretty good
picture of disc quality. Playback errors can be caused by two things:
Localized defects, and poor pit geometry.
Pit Geometry
In order for a disc to play, the reflected laser beam must generate track-following
and focus servo signals so that the player can follow the track and stay
focused. Generation of the proper servo signals is completely dependent
on the size and shape of the pits on the disc. Without the proper "pit
geometry", the disc will not play reliably.
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