Re: Quick and dirty GPSDO build by F2DC and me.
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To better understand I did some simulations.
Once the measurement time is above 10 seconds the 100ns PPS jitter is no longer relevant given the measurement time and measurement frequency. Drift is a problem as the current feedback loop has no feed forward to compensate for a constant drift so the drift leads to a frequency error In the simulation I have been able to add the feed forward and the drift can be compensated. Its clear that temperature stability will be the main factor determining the frequency accuracy as the feed forward to compensate for the drift requires some measurements to measure the drift and if the drift changes a frequency error will persist In below chart the simulation tries to estimate the drift and correct for it but is unable to calculate the exact drift as the counting of the frequency and the correction of the frequency has limited accuracy. Delta is in Hz, Delta*100 is in 0.01Hz.? -- HBTE Files section:?/g/HBTE/files Erik, PD0EK |