[time-nuts] Thunderbolt Loop Damping

Mark Sims holrum at hotmail.com
Tue Jul 8 12:11:46 EDT 2008



I am calculating plotting the ADEVs (or OADEVs) of the Thunderbolt's own PPS and OSC error estimates.  The values are its estimate in the error of the PPS signal edge/OSC zero crossing to GPS time.  I have queue of 22000 entries that tracks the last 22000 values of PPS and OSC errors.  Every 10 seconds, it calculates and displays the ADEV or OADEVs of all the data in the queue (both a table and a plot).  By the time the queue fills up it gives values out to 10,000 tau.  

Yeah, it's kinda flakey to rely on the device to compare its output signals to its own interpretation of GPS time,  but it's free and requires no external equipment.  

The adding of the 1.0 second to the error estimate values (and the multiplying of the OSC ppb value by 100) was to simulate the values that an external time interval counter would produce if it was measuring the signals.  Not really needed, but the code was lifted from another application and it was useful for doing some comparisons to some existing data.  (BTW,  the ADEV code was based upon your ADEV1.C)
_________________________________________________________________
It’s a talkathon – but it’s not just talk.
http://www.imtalkathon.com/?source=EML_WLH_Talkathon_JustTalk


More information about the time-nuts mailing list