[time-nuts] Generating a solid PPS from 10Mhz source
vilgotch at bigpond.net.au
Thu Jan 14 23:44:00 UTC 2016
Am I missing something here?
I understand the ease and fun of programming up an AVR as much as anyone but
surely this task could be accomplished easily with a chain of fast
synchronous TTL or CMOS dividers. A resynchronising FF could also be added
at the end to clean up the 1 pps if required. You wouldn't need to worry
about the maths or OBOBs either.
Admittedly you would need more PCB real estate but that shouldn't be a big
deal in most cases.
>> If anyone is interested in the equivalent functionality using an ATTiny25
>> (for instance, if you’re already heavily invested in AVR instead of PIC,
>> like I am), ping me. I’ve privately written code to solve almost the same
>> problem and it could easily be adapted into doing the same job.
>>>> 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?
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