[time-nuts] ? phase comparison or other device

Dr Bruce Griffiths bruce.griffiths at xtra.co.nz
Sat Jun 30 19:22:06 EDT 2007

Pete wrote:
> Magnus,
> This discussion is why I have allowed the ADA4899-1 to saturate in the ZCD
> posted earlier. The transition times up & down in the second stage are 350 
> to
> 400 ns; thus I believe the <50ns overload recovery doesn't degrade the
> measured jitter. With 500MHz 'scope bandwidth, the 1KHz squarewave
> output has <1% over/under shoot & appears noise free at the zero crossing.
> The output transitions are fast enough for my HP 5370A to  show < 1ns
> jitter over 1K or 10K samples.
> Regards,
> Pete Rawson 

Try measuring your circuits output noise spectrum.
Also measure the temperature dependance of its input output phase shift.
What does this tell you about how stable its temperature needs to be to 
limit the phase shift change to a few nanosconds, or even a microsecond?


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