Tom Clark, K3IO wrote: > If you have a 10 MHz oscillator, simply feed it into the "D" > input into a latch clocked by the de-sawtoothed GPS 1PPS. The output of > the latch is a 0 or 1 depending on the precise phase of the oscillator. > You want this latched 0/1 measurement to average to ½ over a long term > (seconds). As the statistics deviate from a 50/50 split, you tweak the > oscillator. The ~1 nsec of residual noise from the sawtooth corrected > GPS rcvr acts a natural dither. No counters, no ramps, no big A/D > converter -- it couldn't be simpler! And if the 10MHz (=> 100 nsec phase > ambiguity) is too fine for your oscillator, then divide it to 5 MHz > (=>200 nsec) or 1 MHz (=> 1µsec). This should be good enough to pull in > a xtal that is off by 1:10e6. > Tom
How does one do robust statistical filtering of outliers when one uses this technique?? Bruce > I hope these comments helped a bit -- 73, Tom > _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
