Guru
Joined: 07/09/2016
Location: United KingdomPosts: 2170
| 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.