[time-nuts] UBLOX GPS board testing

[Jochen Frieling]

On Tue, 21 Dec 2010 15:26:54 -0600, John Green wrote:
> I tried substituting the 1 PPS output from the Z3801 and comparing it
> to its own 10 MHz output and find the same jumpy behavior as I get
> with the UBLOX boards. Well, not exactly the same but pretty much. Now
> I am confused. I expected the 1 PPS to be in lock step with the 10
> MHz.

With a Z3815A (Furuno receiver, E1938A oscillator) I noticed the PPS
to jump up and down by 2 ns pk-pk in average. On a plot of phase
difference to a more stable 10 MHz source, the upper and lower values
formed two lines, leading to the assumption of it being quantization
steps. (The time interval measurement resolution was significantly
better, using a HP 5370B.)
I have since dropped the idea of using this PPS for stability
measurements by feeding it to the TIC and will use a PPS externally
divided down from 10 MHz instead.


-- 
Neu: GMX De-Mail - Einfach wie E-Mail, sicher wie ein Brief!  
Jetzt De-Mail-Adresse reservieren: http://portal.gmx.net/de/go/demail