[time-nuts] WWVB format change in 2012

[James Flynn]

Sanjeev Gupta <ghane0 at ...> writes:


> that as a result of the change, precision equipment may not be able to
> recover a usable signal from the new modulation scheme, rendering it
> useless for the sub-100 microsec disciplining.

In fact, the new scheme may actually help with accurate ON-TIME 
determination.  Currently, I have a proof-of-concept research system 
running that routinely keeps time to well within the rather broad 100 uS 
range when compared to GPS. This system does not yet use the phase 
information, but uses other techniques to extract the ON-TIME information 
from the signal (which still has to be corrected for propagation delays.) 
Future work will include using the phase information and I am confident 
this will only improve the results.

> A supplementary question: If you have your own homebrew for these 
signals,
> do you use them as a refclock for NTP?

While the proof-of-concept system is not being used for a refclock for 
NTP, it is able to keep time as described above and FREQUENCY to the under 
1 E-10 range. I am still working to improve that and hope to verify it in 
a way directly traceable to NIST.

James Flynn
California State University Northridge