Hi Bill,
On 05/07/2012 05:12 AM, Bill Hawkins wrote:
Thanks for the analysis, Magnus.
Always happy to contribute.
A few other time constants might be interesting -
When a step change is made to the control voltage or current,
how long does it take for the oscillator to settle down to a
new
Magnus,
If you flip back and forth, then it makes sense because your phase
deviations will be less.
Can you further explain this? Thanks.
On Mon, May 7, 2012 at 8:57 AM, Magnus Danielson mag...@rubidium.dyndns.org
wrote:
Hi Bill,
On 05/07/2012 05:12 AM, Bill Hawkins wrote:
Thanks for
OK, got it. Yes, something like the dithering with a DAC to increase the
resolution.
On Mon, May 7, 2012 at 6:52 PM, Magnus Danielson mag...@rubidium.dyndns.org
wrote:
Azelio,
On 05/07/2012 09:56 AM, Azelio Boriani wrote:
Magnus,
If you flip back and forth, then it makes sense because
Hi Azelio,
On 05/07/2012 10:13 PM, Azelio Boriani wrote:
OK, got it. Yes, something like the dithering with a DAC to increase the
resolution.
Indeed. Now, consider now that the variations can come from any form of
noise source.
Another thing I've learned is that the longer you wait with a
Yes, interesting, now I realize... but:
the larger the deviation becomes and lower frequency it will have... and
both makes it harder to suppress by filtering.
Filtering at what level? Lengthen the sampling time? The average build up?
That is, now I'm not aware and think that I have to correct as
On 05/07/2012 10:59 PM, Azelio Boriani wrote:
Yes, interesting, now I realize... but:
the larger the deviation becomes and lower frequency it will have... and
both makes itharder to suppress by filtering.
Filtering at what level? Lengthen the sampling time? The average build up?
That is,
Well, so given the goal (stability at tau, for example) find the best
measure and adjust rates (maybe they are not the same) given the
oscillator-to-be-disciplined characteristics.
On Mon, May 7, 2012 at 11:44 PM, Magnus Danielson
mag...@rubidium.dyndns.org wrote:
On 05/07/2012 10:59 PM,
In message 20120506021212.ec21a800...@ip-64-139-1-69.sjc.megapath.net, Hal
Murray writes:
p...@phk.freebsd.dk said:
If you cannot apply the negative sawtooth, you will get better results by
disciplining almost any random quartz xtal, ovenized or not to the GPS,
divide it down to PPS and then
On 05/06/2012 08:47 AM, Poul-Henning Kamp wrote:
In message20120506021212.ec21a800...@ip-64-139-1-69.sjc.megapath.net, Hal
Murray writes:
p...@phk.freebsd.dk said:
If you cannot apply the negative sawtooth, you will get better results by
disciplining almost any random quartz xtal, ovenized
Poul
I agree, 1PPS from many GPS engines, if sawtooth correction is not used, can
add all sorts of errors like hanging bridges.
Some can sound really bad, like non zero bias over short or very long time
periods and 12 ns of early or late wonder.
It's interesting to talk about these problems,
Here is a different tactic for disciplining Rb from GPS/TXCO -
Consider the relatively (relative to a second) long stability of
an Rb oscillator and the not-so-good stability of GPS. Perhaps
using 1 PPS for a sampling period for stabilizing Rb is way too
short. Maybe 1000 seconds is better.
of the
ionosphere.
Regards
Randall
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf
Of Bill Hawkins
Sent: Monday, 7 May 2012 7:02 a.m.
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] Interesting paper: Don't
On 05/06/2012 09:01 PM, Bill Hawkins wrote:
Here is a different tactic for disciplining Rb from GPS/TXCO -
Consider the relatively (relative to a second) long stability of
an Rb oscillator and the not-so-good stability of GPS. Perhaps
using 1 PPS for a sampling period for stabilizing Rb is way
4:45 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] Interesting paper: Don't GPSD' your Rb...
On 05/06/2012 09:01 PM, Bill Hawkins wrote:
Here is a different tactic for disciplining Rb from GPS/TXCO -
Consider the relatively (relative to a second) long stability of
an Rb oscillator
On 05/03/2012 11:29 PM, Poul-Henning Kamp wrote:
This is pretty think, but interesting:
http://tf.nist.gov/sim/Papers/Trigo_CPEM_2010.pdf
I interpret this as a GPS slaving of the rubidium.
Given that there is fairly high stability in both sources, the
comparison rate does not have to be
-
From: Magnus Danielson mag...@rubidium.dyndns.org
To: time-nuts@febo.com
Sent: Saturday, May 05, 2012 3:33 AM
Subject: Re: [time-nuts] Interesting paper: Don't GPSD' your Rb...
On 05/03/2012 11:29 PM, Poul-Henning Kamp wrote:
This is pretty think, but interesting:
http://tf.nist.gov/sim/Papers
In message CDAA55B4E94149A6972740E6FD0C8C53@Warcon28Gz, WarrenS writes:
Magnus wrote:
This is not a paper about Don't GPSD your RB, as the nut subject line
suggest.
Actually, that is their point, or maybe more specifically: Don't GPSDO
it the way we do with OCXOs.
At least as I read the
Thanks, Poul
If that was their point then, I missed it completely.
The way I read it, I think you are giving them WAY too much credit about
them understanding subtle things like that.
Yes we do agree that using low accuracy 1PPS signals can cause some
unforeseen problems.
They are using 10
Hi Poul-Henning,
On 05/05/2012 08:35 PM, Poul-Henning Kamp wrote:
In messageCDAA55B4E94149A6972740E6FD0C8C53@Warcon28Gz, WarrenS writes:
Magnus wrote:
This is not a paper about Don't GPSD your RB, as the nut subject line
suggest.
Actually, that is their point, or maybe more specifically:
p...@phk.freebsd.dk said:
If you cannot apply the negative sawtooth, you will get better results by
disciplining almost any random quartz xtal, ovenized or not to the GPS,
divide it down to PPS and then discipline the PRS10 to that.
I don't understand that. What am I missing?
In the simple
Sure? Now, this is interesting. Now I'm using the serial port to apply the
correction as it seems that the EFC is 8bit sampled and then applied to the
DAC which drives the C-field, so better directly use the DAC with the Fxx
command. Any clue about the X command? It is undocumented and seems to
This is pretty think, but interesting:
http://tf.nist.gov/sim/Papers/Trigo_CPEM_2010.pdf
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be
OK, I've read the paper. Why not GPSDiscipline your Rb? GPSDiscipline cum
grano salis but do it. My LPFRS GPS disciplinator hardware is ready. OK, I
know, the 1E-11 step is too large but I'll try. First I'll take
measurements so that I can think about a disciplining algorithm. Then a
hardware
: Thursday, May 03, 2012 6:06 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Interesting paper: Don't GPSD' your Rb...
OK, I've read the paper. Why not GPSDiscipline your Rb? GPSDiscipline cum
grano salis but do it. My LPFRS GPS disciplinator hardware is ready
: Thursday, May 03, 2012 6:06 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Interesting paper: Don't GPSD' your Rb...
OK, I've read the paper. Why not GPSDiscipline your Rb? GPSDiscipline cum
grano salis but do it. My LPFRS GPS disciplinator hardware is ready
Of Azelio Boriani
Sent: Thursday, May 03, 2012 6:06 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Interesting paper: Don't GPSD' your Rb...
OK, I've read the paper. Why not GPSDiscipline your Rb? GPSDiscipline cum
grano salis but do it. My LPFRS GPS
-nuts-boun...@febo.com]
On Behalf Of Azelio Boriani
Sent: Thursday, May 03, 2012 6:06 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Interesting paper: Don't GPSD' your Rb...
OK, I've read the paper. Why not GPSDiscipline your Rb? GPSDiscipline
cum
On Thu, May 3, 2012 at 5:01 PM, Brian, WA1ZMS wa1...@att.net wrote:
I once had a high level manager hold an all employee meeting in which he
started his talk by saying that
Nothing difficult is ever easy. Needless to say...he didn't last
long in his job and left the company.
Yes but
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