slightly ot: DAT clock deviation

[danial stocks]

>
>Does anybody know about usuall DAT clock jitter and drift specs?
>I mean the sampling frequency should be 48.00000 kHz, but
>there will be offset, drift (temperature) and long term drift (aging).
>I'm especially interested in short term drift (1s-100s).
>
most decent DAT machines should be XTL locked for all clock/sampler 
functions. as such, drift should be of the order of stability as is an XTL 
osc {10 ppm? not sure..} if you want better, you could open the DAT up and 
put some heat insulation around the XTL. Jitter, dont know, it will be a 
function of the internal on chip dividers - tho it shouldn't be too bad as 
these usually are a direct divide rather than PLL. Experiments I've done on 
CD players indicate you can inject an external signal into the xtl clock 
[removing the xtl and associated components first] so I'd imagine you could 
do the same mod on DAT's , tho I've never had the oppourtunity to try it 
out. Thus if you like, you could perhaps drive it from a diy mega stable 
clock srce, or make it pitch controlled [this works really well on CD 
walkmans!!]
Cheers,
Dan
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