[time-nuts] Gate propagation delay jitter
SAIDJACK at aol.com
SAIDJACK at aol.com
Tue Apr 10 19:50:45 EDT 2007
In a message dated 4/10/2007 14:33:17 Pacific Daylight Time,
bruce.griffiths at xtra.co.nz writes:
Yes ground bounce can play havoc with the effective switching thresholds.
One would expect this effect to be much worse with single ended clocks.
Bruce
Hi Bruce,
not to give away too much, but in our Jackson-Labs Fury GPSDO we compensate
for VDD bounce as well by having fully-differential circuits with special
current balancing circuitry.
Thus not only do clocks have to be differential, but every output of the
circuit should be differential as well to balance the VDD currents.
This helps prevent feeding noise into the VDD rails, which can show up at
other IC's. We were able to completely get rid of spurs in our phase noise
measurements with this technique.
bye,
Said
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