[time-nuts] Frequency counter questions

[Jerry Hancock]

Hello,  I would like to find a person that would be able to answer some frequency counter questions I have.  

Basically, I am thinking of building my own using one of the high end STM32F7 boards as the counter.  I would like it to count reliably to 12 digits (e.g. 30,000,000.001x hz).  I am not worried about input conditioning as I have a circuit that is suitable for my needs.  Most of my questions have to do with using a prescaler on the front (divide by N where what is N) to get to the desired resolution when using multiples of the PPS coming from my GPSDO.  Gate times could be as long as needed to get the resolution.  So what prescaler do I need and what gate time is required are the first two questions.  I suggest if someone is willing to help that they either reply here with an email address or send a note to meters at hanler dot com.  This is for my own non-commercial use.

Thanks!

Jerry