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AD9548 - 1PPS Quantisation Error Compensation

Question asked by Fred1 on Apr 9, 2012
Latest reply on Apr 12, 2012 by Fred1

Hi,

 

I am wondering if there is a way to compensate for quantization errors on an 1PPS pulse from a GPS receiver.

 

Most GPS receivers add a quantization error to the 1PPS output because their internal oscillator is not locked to GPS. This timing error can be read from the GPS receiver and represents the timing error of the following time pulse in [ps]. This would give the system approx. 1 second reaction time to "adjust" the AD9548 for the timing error of the next 1PPS via serial port. Being able to do that would reduce the jitter of the 1PPS reference input from approx. +/-30ns to +/-15ns RMS according to the receiver datasheet. I would expect this has some effect on the stability of the filtered output frequency of the AD9548.

 

Any ideas if that can be done and if that would lead to an improved stability of the AD9548 clock output?

 

Regards,

Fred

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