Open source GPS-disciplined frequency generator.

• Open source GPS-disciplined frequency generator.
  Posted by rcls on 08 Dec, 2025 18:37
• 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.
  
  
• #1 Reply
  Posted by DimitriP on 09 Dec, 2025 19:03
• I like a grand entrance!
  Welcome to the forum
• #2 Reply
  Posted by 5U4GB on 11 Dec, 2025 05:15
• Nice, and nice detailed writeup!  Have you thought about submitting it to Silicon Chip as a project?
• #3 Reply
  Posted by rcls on 14 Dec, 2025 20:28
• Thanks for the suggestion, I'm looking into it.
• #4 Reply
  Posted by 5U4GB on 15 Dec, 2025 03:30
• 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.