Browse over 10,000 Electronics Projects using the Page Numbering provided at the bottom of each Page.

GPS Disciplined Oscillator review and teardown

GPS Disciplined Oscillator review and teardown

Andy Brown did a teardown of a GPS Disciplined Oscillator:

The design did actually surprise me. I was expecting to see an OCXO pulled from something else together with a modern GPS unit and an MCU to co-ordinate the synchronisation all mounted on a custom PCB. What we’ve actually got is an entire Symmetricom GPSDO pulled from some other device and mounted on to a trivial minimal PCB that does nothing more than break out connections to the front panel.

One of the basic requirements for building a frequency counter is the ability to calibrate it and to do that you need to have a reference clock source that you can rely on to be more accurate than the device you’re trying to calibrate. For my purposes that meant either a rubidium clock or a GPS Disciplined Oscillator (GPSDO).



Advertisement


Rubidium clocks are very precise, having an Allan Deviation (adev) of 10-12 but they do require periodic calibration which makes it difficult to trust the used devices that you can get on ebay.

By contrast, a GPSDO is a hybrid device that relies on a relatively cheap oscillator that is very accurate in the short term and can be gently nudged (disciplined) into line in the long term by a time signal received from GPS satellites. These devices never need calibrating but they do have a finite lifespan which is something I’ll explain when we get into the detail.

 

 




Top