GPS Frequency Stability

I couldn’t find a nice graph showing the timing performance of a single-frequency, sawtooth-corrected, pulse-per-second output from a GPS. So I measured a CNS-II GPS Clock and a surplus telecom HP Z3805A GPS Disciplined Oscillator (GPSDO) against a high-performance Cesium standard for 30 days. Here are a whole bunch of pretty pictures of the results for my (or your) future reference.

First, here are Allan Deviation, Time Deviation, phase difference, and frequency difference plots of the 30-day period (Note that the ADEV of the Z3805 at tau less than a few hundred seconds is limited by the noise floor of the TICC timestamping counter).





Here is a phase difference plot with 1000 second averaging; this gets rid of a lot of the fuzz and makes it easier to see trends.


Here are some zoomed-in plots that show the short-term jitter of the sawtooth-corrected GPS and GPSDO.






Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.


USR-IOT Serial-to-Ethernet Converters with Linux

I'm posting this mainly because Google didn't turn up any help when I queried about using the USR-IOT serial port…

Mini-Circuits Power Amp

Each year at the Dayton Hamvention, the folks at Mini-Circuits have a bunch of odds and ends they sell very…

Oscillator Aging Trends

It's well known that just about all oscillators drift, or "age", in frequency with time. In crystal oscillators, the most…

HP 5065A Status

My faithful HP 5065A Rubidium standard, which had been converted to a "Super" model, developed an intermittent sickness and back…