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Keith956 · 22nd Oct 2021, 10:03 am

Richard,
I managed to get a Jupiter T board and Isotemp VCXO working with a similar arrangement to your circuit (dividing the Isotemp 10MHz output down to 10KHz and locking to the Jupiter).

It seems stable to 11 digits on my HP53132A that has its own OXCO after a hour or so's warmup. 10MHz +/- 5mHz or better, the variance may be the 53132A, but without another GPSDO to compare I've no way of knowing.

A question: why did you use a CD4046 PLL rather than the James Miller 7486 XOR as a phase comparator? I've tried both and can't see any obvious difference in performance.

Keith

22nd Oct 2021, 10:03 am	#21
Keith956 Heptode Join Date: Jun 2019 Location: Oxfordshire Posts: 740	Re: Finally a GPSDO that works Richard, I managed to get a Jupiter T board and Isotemp VCXO working with a similar arrangement to your circuit (dividing the Isotemp 10MHz output down to 10KHz and locking to the Jupiter). It seems stable to 11 digits on my HP53132A that has its own OXCO after a hour or so's warmup. 10MHz +/- 5mHz or better, the variance may be the 53132A, but without another GPSDO to compare I've no way of knowing. A question: why did you use a CD4046 PLL rather than the James Miller 7486 XOR as a phase comparator? I've tried both and can't see any obvious difference in performance. Keith