Open source GPS-disciplined frequency generator.

[rcls]

Hi,

I made an open hardware & open source GPS disciplined frequency generator with output frequencies from 1Hz to 1.6GHz.  https://github.com/rcls/gpsfreak

The device outputs four separately programmable frequencies (from 2 PLLs) onto SMA connectors, with GPS used as the source for a reference time base.

The clock generator is a TI LMK05318b bulk-acoustic wave oscillator.  This device is pretty flexible and has very low phase noise, in the same ball-park as a decent crystal oscillator (I don't have equipment capable of measuring it).

Short term frequency accuracy is determined by GPS and should be under 1ppb.  It can be built with either a U-Blox MAX-M10S (low cost) or MAX-F10S (dual
frequency) GPS module.

There is firmware, plus python scripts for controlling the device from a PC. (Configurations can be saved to flash for disconnected operation).

Manufacturing with JLCPCB and hand-soldering select components (connectors and the more obscure passives), you can build two units at approx US $50 each.

Cheers,
Ralph.

[DimitriP]

I like a grand entrance!
Welcome to the forum

[5U4GB]

Nice, and nice detailed writeup!  Have you thought about submitting it to Silicon Chip as a project?

[rcls]

Thanks for the suggestion, I'm looking into it.

[5U4GB]

Just realised my note was a bit ambiguous, I meant it'd quality as a full-blown article, not just their reader-contributed circuit ideas at the back of the issue.

[SCSKITS]

Would be nice to have a PDF in the GITHUB of the schematic and maybe the board layout.

[rcls]

Hi,

I have added PDFs to the git repo:
https://github.com/rcls/gpsfreak/blob/main/gpsfreak-sch.pdf
https://github.com/rcls/gpsfreak/blob/main/gpsfreak-pcb.pdf

Cheers,
Ralph.