Measuring pulse shorter than 1 microsecond


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Volhout
Guru

Joined: 05/03/2018
Location: Netherlands
Posts: 2027
Posted: 07:00am 07 Sep 2022      

Just for my understanding, can you elaborate a bit ?

1/ Are you using micromite or picomite (picomite has a PIO (hardware block) that could help you with this).
2/ You are measuring period (1us) once per 100ms. IS this a 1us pulse that repeats every 100ms, or is it a continuous clock that you want to measure and update your reading every 100ms?
3/ What is the desired resolution when measuring the 1us period. You talk about averaging a number that is 39,40 or 41 ? (40MHz clock).

I think what you want is possible using a picomite, that has a PIO state machine that can measure your signal with a clock of 62.5MHz, with 2 clocks per per sample, this is 31.25MHz (not 40), so a single period would give a reading of 31.

In case it is a continuous clock, you could also count 100 cycles (100ms). You would need 3 clocks per sample. In that case the virtual resolution would be 20.833*100=2GHz.

Regards,

Volhout
Edited 2022-09-07 17:01 by Volhout