3 ms·
So many great rabbit holes in this list. There are several that have blown years of my spare time. My one, at the moment is precision time keeping. Time nuts.
by mianos 2y ago
So many great rabbit holes in this list. There are several that have blown years of my spare time.
My one, at the moment is precision time keeping. Time nuts. I have a pile of oven controlled crystal oscillators, GPSs (even the full Ublox time specific LEA M8).
I got a BG7TBL counter and multiple cheap GPSDOs to test my own.
I have a DAC1220 20 bit DAC on an ESP32 disciplining a TCXO from an old phone base station by counting the 10Mhz using the PCNT and gated off the GPS 1PPS.
Meantime, I learnt the esp-idf so I could have more control over things. Everything done with the esp-idf is way way more stable than using the Arduino wrapper, no idea why, maybe later versions?
The disciplining/tracking parameters are exposed by http and mqtt and put into influx.
I have a 5.5 digit multiple meter (I repaired the classic HP 3478A). Maybe I need another digit, there goes another rabbit hole. Voltnuts.
- rapjr9 2y agoYou might explore clock hardware used in the film and music industries. Ranges from $200 temperature controlled audio clocks to very expensive video black generators. Some links to get started: https://www.sweetwater.com/c953--Synchronizers https://www.sweetwater.com/c953--Synchronizers https://en.wikipedia.org/wiki/Black_and_burst https://en.wikipedia.org/wiki/Black_and_burst https://www.sweetwater.com/insync/black-burst/ https://www.sweetwater.com/insync/black-burst/ https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=rosendahl+nanosync&_sacat=0&_odkw=rosendahl&_osacat=0 https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m... Might be interesting to convert an audio precision word clock into a precision computer clock. Audio atomic clocks are available ($7000): https://en.antelopeaudio.com/products/10mx/ https://en.antelopeaudio.com/products/10mx/
- mianos 2y agoI assume my GPS disciplined over controlled crystal oscillator is going to be much the same as most of those. Short term .1milli Hz. Without GPS, yes a rubidium oscillator would be fun to have and the phase noise is may be better than the TCXO disciplined oscillator, but the system I have with the LEA-M8T with a good external antenna and used in the 'base station surveyed in' mode is more stable. I've been keeping an eye on ebay for old one at a reasonable price. They do wear out so it's a risky buy. The black burst stuff is funny. I used to work in TV as a kid. The plate on my car was PAL-443