What about the phase jerk (details given in the datasheet) applied to
the 10KHz burst once per second?
Bruce
Azelio Boriani wrote:
Timing GPS receivers usually have the sawtooth correction message and I saw
an application of a delay line to correct the PPS before using it. Of
course if you time the PPSes difference with a time-to-digital you don't
need to correct the incoming hardware PPS by a delay line, but to implement
an all-analog PPS PLL then it can be done. For those of you who use a 10KHz
reference signal there is not even the need for a long time constant in the
low pass filter: to average 1000 PPSes you need 1000 seconds but to average
1000 10KHz cycles you need only 0.1 seconds.
On Mon, Jan 30, 2012 at 6:15 AM, David<[email protected]> wrote:
The sawtooth error in the PPS output and how they were able to correct
it externally was interesting. I have seen that kind of problem
before in DDS and other applications.
I wonder what other GPS receivers provide either PPS outputs without
sawtooth noise or a correction message.
On Sun, 29 Jan 2012 20:40:52 -0800, Hal Murray
<[email protected]> wrote:
What do you mean by "average"? Do you mean that the GPS and PLL must be
kept on for "20 minutes to hours", or did you mean that the PLL loop
filter
must have a time constant of 20 minutes to several hours?
You have to compare the characteristics of the oscillator with the
characteristics of your GPS receiver.
If your local oscillator is very stable, then you want to average over
long
times (hours, days). If your local oscillator is a good thermometer and
you
have a very good GPS receiver, then you want a shorter time constant
(minutes) so you can track temperature changes.
Do you know about hanging bridges? If not, please read Timing for VLBI by
Tom Clark and Rick Hambly. It's got some wonderful graphs. Once you
understand those, this discussion will get much more interesting.
http://gpstime.com/files/tow-time2009.pdf
_______________________________________________
time-nuts mailing list -- [email protected]
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- [email protected]
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- [email protected]
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
