[time-nuts] How to measure Allan Deviation?
John Ackermann N8UR
jra at febo.com
Sun Oct 22 21:17:20 EDT 2006
Dr Bruce Griffiths said the following on 10/22/2006 08:24 PM:
> Reading between the lines on the Jupiter GPS receiver datasheet it would
> appear that the 10KHz output is phase modulated at 1Hz to realign it to
> successive PPS output pulses. As the PPS jitters about so does the 10KHz
> signal.
> Most GPS receivers with higher frequency outputs than 1Hz, phase
> modulate the high frequency output in this way and the datasheets
> explicitly indicate this.
>
> Thus there would appear to be little advantage in phase locking to the
> 10KHz signal with a short loop time constant.
Hi Bruce --
I believe you're correct that the 10kHz output jitter is not any better
than the 1 PPS jitter; there's been some confusion about that in some of
the projects that use the Jupiter receivers.
John
More information about the time-nuts
mailing list