Clock Crystal Accuracy

[poynton]

.
I know that the frequency of my CD player is 16.9344MHz.

What difference would it make using a clock oscillator with a frequency of 16.9340MHz?


Andy

 

[martin clark]

That's 400ppm low.

Somewhere in the back of my mind I thought Red Book cd recommends +/-200ppm; I might be wrong on that.

Practically, as a clock in a standalone CD player - no issue at all: - it's the close-in LF phase noise ('goodness' of teh clock source) that seems to make a difference. *

that said, if you plan on using he result as a transport to a dac - probably won't matter, but it might depending on how tight/ exactly how that dac is programmed to lock to the datastream.


* musically - 400ppm low average is likely >= 2dec places below what even the finest human sense of pitch can perceive; so no issue at all, muscally

 

[martin clark]

Edit - got my maths wrong; that's only 25ppm out. Don't worry about it.

 

[Mike P]

Martin is right (as usual).

What matters for audio (assuming use as a single box player) is 'jitter' of the clock signal. As long as it's within sensible tolerances the absolute frequency of the clock being a tiny amount out doesn't matter, it won't be audible.