Frequency Measurement


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CaptainBoing

Guru

Joined: 07/09/2016
Location: United Kingdom
Posts: 1230
Posted: 08:39pm 22 Jun 2018      

I built a Frequency meter with a USB serial interface on an old euro card.

I wanted it absolutley perfect to whole Hz and used a "gold" TCXO at 12.288MHz 100ppb as the reference XTAL and divided it down to give a very precise 1 second gate into that same 8154.

It was more involved than that one above because I divided down using discrete counter chips (4017s !), I didn't want to rely on a processor clock for the gate, but it is incredibly accurate and good from 0Hz to about 70MHz in 1Hz increments

I have a small vid of it working here. https://www.youtube.com/watch?v=pakCeRi2fJQ&t=97s

If you are interetsed, I can bundle the circuit schematics in Eagle and post them. It was originally powered by a PIC16F877 but was the subject of a brain transplant to a 44pin micromite. It has given sterling service and is a daily driver for me.

I intend to put a frequency generator in the same case... one day... just need to get round to it.Edited by CaptainBoing 2018-06-24