[time-nuts] 1PPS to 32.768 khz

Lee - N2LEE lee at n2lee.com
Wed Oct 19 10:15:14 EDT 2016

You guys are great. I especially like the more creative solutions that could take this project to a different level.

I should have known that my request was not a simple one. :)

While going from 1 PPS to 32.786 is not as easy as I had hoped what I find odd is that others must have been
looking for this same solution. Hard to believe an innovative chip designer has not solved this problem.

I have been able to find solutions that come close.
For example Epson /Seiko makes a RTC chip with a built in TCXO that will let you use the devices 32khz oscillator and
it allows for 1 PPS input. BUT (always a but) I don't think it corrects the oscillator just the RTC clock. (I think).


I have to tell you guys the recommendations I am getting are great even if they don't solve my exact solution.
The reason is you are giving me a lot to think about and research which means I am learning. I LOVE That ! :)

Keep the ideas coming and thanks for your patience.


On Oct 19, 2016, at 9:15 AM, Dave Martindale <dave.martindale at gmail.com> wrote:

> If the "big digital clock" doesn't display the time with fractional-second precision, then it only needs to be updated at 1 Hz, which can be done with the 1 PPS directly.  Consider replacing the 32 kHz crystal, divider chain, and microprocessor with a new microcontroller that takes 1 Hz input and drives the display in the same way.
> For an extra bonus, use a microcontroller with a serial port, and connect the GPS receiver serial output to the serial port on the micro.  Then you can decode the serial data stream from the GPS, and automatically set the clock to the correct time after a power failure - something the original clock could not do.  As a double bonus, make the clock display leap seconds correctly when they happen.
> - Dave
> On Tue, Oct 18, 2016 at 10:03 PM, Lee - N2LEE via time-nuts <time-nuts at febo.com> wrote:
> 1. Does anyone know of a device that will take a 1PPS GPS timing signal and generate a 32.768 kHz sine wave output ?
> I have big digital clock that uses an 8 bit micro processor and an external 32.768 crystal. Obviously the external crystal is
> awful for accuracy.

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