[time-nuts] from Sputnik to CD

Thomas A. Frank ka2cdk at cox.net
Sat Oct 6 19:17:19 EDT 2007

> If the sample rate is 44.1 kHz then the adev below 1 s, even
> down to 10 us, or jitter, or the phase noise above 1 kHz are
> they key parameters; not long-term drift. In this case I'd take
> a nice 10811A over a typical Rb any day. Does anyone know
> for sure, or am I off base here?


I think you've hit the nail on the head here.  Jitter is most likely 
the key parameter; a little bit of drift probably would not be noticed.

I wonder if the real problem is not the noise that would be generated 
by jitter, but phase errors between channels?  The ear is quite good at 
determining the phase of arriving signals; if, during playback the 
timing jumped between the decoding of the left and right channel some 
interesting artifacts might appear, and they would not be -90dB, they 
would be at the level of the playback signal being an actual error in 
the reproduction.

I will say that I wish the 'record' companies would put a little more 
effort into the accuracy of their clocks.  I've come across CD's that 
were obviously recorded with a control clock that was in error, since 
on playback the actual sound was 'slow' (and yes, I tried it on several 
players to make sure it was really the CD).

But no one has commented on the song...

Another Tom

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