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Discussion of precise time and frequency measurement

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GPSDO TC & Damping

MS
Mark Sims
Sat, Jan 10, 2009 5:38 AM

The good Lady Heather's GPS Disciplined Oscillator Controller Program calculates and plots  (also writes the results to the log file) ADEV and OADEV of the Thunderbolt's reported error estimates.  My comparison of these "auto-ADEVs" to the values generated from a Tek DC5010 counter showed they agreed within a factor of two.

Note that the DC5010 was measuring the Thunderbolt 10 MHz signal against a 1 MHz cesium reference.  The data had to be massaged some where the phase rolled over (the DC5010 counter has a 5 nsec or so bogus zone where the time interval is wrapping).  The counter was set up to calculate time intervals over 10 seconds (to get picosecond resolution) so ADEVs below 10 seconds were not available.


What does the plot of ADEV vs tau look like when the Thunderbolt OCXO is
unlocked and one just logs the Thunderbolt's own measurements of the
phase and frequency errors.
It should exhibit a minimum at a value of certain value of tau.


Windows Live™: Keep your life in sync.
http://windowslive.com/explore?ocid=TXT_TAGLM_WL_t1_allup_explore_012009

The good Lady Heather's GPS Disciplined Oscillator Controller Program calculates and plots (also writes the results to the log file) ADEV and OADEV of the Thunderbolt's reported error estimates. My comparison of these "auto-ADEVs" to the values generated from a Tek DC5010 counter showed they agreed within a factor of two. Note that the DC5010 was measuring the Thunderbolt 10 MHz signal against a 1 MHz cesium reference. The data had to be massaged some where the phase rolled over (the DC5010 counter has a 5 nsec or so bogus zone where the time interval is wrapping). The counter was set up to calculate time intervals over 10 seconds (to get picosecond resolution) so ADEVs below 10 seconds were not available. ----------------- What does the plot of ADEV vs tau look like when the Thunderbolt OCXO is unlocked and one just logs the Thunderbolt's own measurements of the phase and frequency errors. It should exhibit a minimum at a value of certain value of tau. _________________________________________________________________ Windows Live™: Keep your life in sync. http://windowslive.com/explore?ocid=TXT_TAGLM_WL_t1_allup_explore_012009
BG
Bruce Griffiths
Sat, Jan 10, 2009 5:57 AM

Mark Sims wrote:

The good Lady Heather's GPS Disciplined Oscillator Controller Program calculates and plots  (also writes the results to the log file) ADEV and OADEV of the Thunderbolt's reported error estimates.  My comparison of these "auto-ADEVs" to the values generated from a Tek DC5010 counter showed they agreed within a factor of two.

Note that the DC5010 was measuring the Thunderbolt 10 MHz signal against a 1 MHz cesium reference.  The data had to be massaged some where the phase rolled over (the DC5010 counter has a 5 nsec or so bogus zone where the time interval is wrapping).  The counter was set up to calculate time intervals over 10 seconds (to get picosecond resolution) so ADEVs below 10 seconds were not available.


What does the plot of ADEV vs tau look like when the Thunderbolt OCXO is
unlocked and one just logs the Thunderbolt's own measurements of the
phase and frequency errors.
It should exhibit a minimum at a value of certain value of tau.


Windows Live™: Keep your life in sync.
http://windowslive.com/explore?ocid=TXT_TAGLM_WL_t1_allup_explore_012009


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Mark

Where these results obtained when the Thunderbolt OCXO was locked?

Bruce

Mark Sims wrote: > The good Lady Heather's GPS Disciplined Oscillator Controller Program calculates and plots (also writes the results to the log file) ADEV and OADEV of the Thunderbolt's reported error estimates. My comparison of these "auto-ADEVs" to the values generated from a Tek DC5010 counter showed they agreed within a factor of two. > > Note that the DC5010 was measuring the Thunderbolt 10 MHz signal against a 1 MHz cesium reference. The data had to be massaged some where the phase rolled over (the DC5010 counter has a 5 nsec or so bogus zone where the time interval is wrapping). The counter was set up to calculate time intervals over 10 seconds (to get picosecond resolution) so ADEVs below 10 seconds were not available. > > > > ----------------- > > What does the plot of ADEV vs tau look like when the Thunderbolt OCXO is > unlocked and one just logs the Thunderbolt's own measurements of the > phase and frequency errors. > It should exhibit a minimum at a value of certain value of tau. > > > _________________________________________________________________ > Windows Live™: Keep your life in sync. > http://windowslive.com/explore?ocid=TXT_TAGLM_WL_t1_allup_explore_012009 > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Mark Where these results obtained when the Thunderbolt OCXO was locked? Bruce