B
budgie
- Jan 1, 1970
- 0
Well, it's probably jitter and "wobble" as well ....
I have a PLL with a 10MHz xtal oscillator, comparison frequency 10kHz, reference
source being a GPS receiver which outputs 10k. This all works very well, but I
was hoping to somehow quantify the residual phase variation, and without
requiring particularly elaborate gear.
I've done visual comparisons on the CRO with the OCXO timebase oscillator in my
frequency counter, which showed no discernible wobble in the phase relationship.
I've also fed the buffered 10MHz into the counter which resolves to 1Hz (1 sec
gate) and the variation in this "sampling" is the 1Hz you'd expect in a sampled
stream (10,000,000 or 10,000,001).
I've also listened to the 10MHz on a narrowband FM receiver 9comms test set) and
can't discern any change in the residual instrument noise when the oscillator is
on or off, but that only indicates that the comms test set has a noise floor.
I can work out the freq/voltage slope at the varicap and watch the control
voltage on a CRO, but that is going to incorporate additional effects into the
calculation.
Any suggestions welcome.
I have a PLL with a 10MHz xtal oscillator, comparison frequency 10kHz, reference
source being a GPS receiver which outputs 10k. This all works very well, but I
was hoping to somehow quantify the residual phase variation, and without
requiring particularly elaborate gear.
I've done visual comparisons on the CRO with the OCXO timebase oscillator in my
frequency counter, which showed no discernible wobble in the phase relationship.
I've also fed the buffered 10MHz into the counter which resolves to 1Hz (1 sec
gate) and the variation in this "sampling" is the 1Hz you'd expect in a sampled
stream (10,000,000 or 10,000,001).
I've also listened to the 10MHz on a narrowband FM receiver 9comms test set) and
can't discern any change in the residual instrument noise when the oscillator is
on or off, but that only indicates that the comms test set has a noise floor.
I can work out the freq/voltage slope at the varicap and watch the control
voltage on a CRO, but that is going to incorporate additional effects into the
calculation.
Any suggestions welcome.