Over the last few weeks I've been playing around with an inexpensive frequency counter that I purchased from ebay for $12. (Translation of PDF Manual attached below) It appears to have a TCXO and displays eight digits. I have (translated) PDF docs for it and it has a decent level of configure-ability. Its supposed to be able to measure frequencies to 2.4 GHz, but I have no idea what it can actually go to in reality.
Anyway, Ive also read a bit about the use of the PIC microprocessor for simple transformations - accurate to picosecond level using these unique it seems PIC chips. Their uses include these described on the leapsecond.com site,
http://www.leapsecond.com/pic/picpet.htm or maybe this is better..
http://leapsecond.com/pic/picpet2.htm http://www.leapsecond.com/pic/http://www.leapsecond.com/pic/picdiv.htmThese are frequency dividers which can be used to derive precise intervals from a 10 MHz standard..
pd03.asm / pd03.hex / PD03 -- "4-pin" 10^3 frequency divider (10 MHz to 10 kHz)
pd04.asm / pd04.hex / PD04 -- "4-pin" 10^4 frequency divider (10 MHz to 1 kHz)
pd05.asm / pd05.hex / PD05 -- "4-pin" 10^5 frequency divider (10 MHz to 100 Hz)
pd06.asm / pd06.hex / PD06 -- "4-pin" 10^6 frequency divider (10 MHz to 10 Hz)
pd07.asm / pd07.hex / PD07 -- "4-pin" 10^7 frequency divider (10 MHz to 1 Hz)
pd08.asm / pd08.hex / PD08 -- "4-pin" 5x10^6 frequency divider (5 MHz to 1 Hz)
pd09.asm / pd09.hex / PD09 -- "4-pin" 10 MHz to 1PPS frequency divider (20 us pulse)
pd10.asm / pd10.hex / PD10 -- "4-pin" 10 MHz to 1PPS frequency divider (10 ms pulse)
pd11.asm / pd11.hex / PD11 -- 10 MHz to 1PPS frequency divider (3 pulse widths), with sync
pd12.asm / pd12.hex / PD12 -- 5 MHz to 1PPS frequency divider (3 pulse widths), with sync
pd13.asm / pd13.hex / PD13 -- 10 MHz to three frequencies divider (1-10-100 Hz), with sync
pd14.asm / pd14.hex / PD14 -- 5 MHz to three frequencies divider (1-10-100 Hz), with sync
pd15.asm / pd15.hex / PD15 -- 10 MHz to three frequencies divider (1-1000-10000 Hz), with sync
pd16.asm / pd16.hex / PD16 -- 5/10 MHz to four frequencies divider (1-10-100-1000 Hz)
pd17.asm / pd17.hex / PD17 -- 1/2.5/5/10 MHz to 1PPS frequency divider (100 ms), with sync
pd18.asm / pd18.hex / PD18 -- 1/2.5/5/10 MHz to 1PPS frequency divider (10 ms), with sync
pd26.asm / pd26.hex / PD26 -- 10 MHz to 1PPS divider, with sync and micro-step
pd27.asm / pd27.hex / PD27 -- 10 MHz to 1PPS divider, with sync and milli-step
pd28.asm / pd28.hex / PD28 -- 10 MHz to sidereal 1PPS divider, with sync and milli-step
The PicPets speak to a microcomputer via a UART.. An out of the box RPI usually has two UARTS, but then you can of course tell a RPI to use additional GPIOs as yet more UARTS if you need more...
The PICs seem like a simple, cheap way to make a great many transforms and timestamp events with timing related value possible in a way that minimizes quantization error..
I also got a low cost (True Position) GPSDO for $42 on ebay. (see thread at
https://www.eevblog.com/forum/projects/gpsdo-loss-of-satellitesfix-troubleshooting/ )
Which is quite a decent GPSDO, as far as I can tell so far. It is getting typically five sats with an indoor antenna and seven if my antenna is outside in the middle of my yard.. But deer like to run through my yard and kept knocking it over.. So now its back inside
It seems to work okay with an indoor antenna once its been going for a while..
it can serve as a 10 MHz standard of known accuracy.
But thats the problem, I have no way of measuring anything else that well, really, yet. As I went looking for counter/timers I found either old classic equipment thats either huge too big for my tiny desk area, or so old its likely to not be as reliable as I'd like it to be. Other equipment will likely require repairs.. If certain parts die they are 'unobtainium'
At the same time I have this new frequency counter that cost $12 thats right on frequency.. I have this surplus GPSDO that I venture to say is likely as good as the timebases that cost $600 that went into the classic HP 5335a Because it has GPS atomic clocks to reference itself to. These PIC chips are also super accurate.
They arent about to become hard to source in the immediate future.
I don't really know much about precise timing at all, besides what Ive read. I'm not some kind of technical whiz at all. I just like learning and saving money and having fun with science and electronics and computers, cheaply.
This has led to my thinking that - why cant it be possible to make a full featured universal counter timer to measure other stuff, using these fairly modern, really cheap elements, and do it right, for less? It seems like all the elements are there? Also, the specs of a device making use of modern hardware in the most cost effective manner possible may end up being as good or perhaps better than the old classic equipment, because silicon and mass production, and using this approach might be less likely to suddenly break or fail and not be fixable.
An open source project like the AVR TransistorTester for time and frequency measurement makes a lot of sense.