[time-nuts] Generating a solid PPS from 10Mhz source - finetuned start

Xavier Bestel xavier.bestel at free.fr
Mon Jan 25 13:55:20 UTC 2016

Hi Guys,

Le mercredi 13 janvier 2016 à 09:22 +0000, Jerome Blaha a écrit :
> Hey Guys,
> Is there an easy circuit to build that can consistently deliver a 1
> PPS from a 10MHz source with excellent resolution and
> repeatability?  My first application is to test different 10MHz
> oscillators without a TIC always attached and then compare the PPS
> output change over time against a master GPSDO PPS with an HP53132A.
> The circuit used for PPS generation would have to deliver consistent
> PPS output with preferably not more than 100ps noise or jitter,
> assuming a perfect source.  I'm totally guessing that for this
> resolution, the PPS would have to be generated and accurate to within
> 0.001Hz every second.  If this is too difficult, maybe the
> integration time can be increased to generate one pulse every
> 10second or every 100,000,000.00 cycles?
> Finally, is a square 10Mhz reference any better in this case than a
> sinusoidal input for generating the PPS?

What would it take to make that PPS adjustable with a step <= 1ns ?
I see that the PIC solution has a mean of "arming" the 1PPS to let it
start at the desired time, but the granularity would be of course
10MHz. For example are there easy-to-use programmable delays to reach
the missing precision ?


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