Hal Murray wrote:
> From the TBolt PPS pin:
> resistor (current limiter)
> diode
> cap to ground
> resistor across cap (decay)
A passive solution along those lines would be ideal, will try
that before anything more elaborate. Doesn't matter if the
resulting pulse isn't symmetric, I just nee
> It ought to be a bit better than this, but the 10uS PPS width is a bit too
> short for a steady timing of centroid through a soundcard at 192k samples/
> sec, I need to stretch the pulse a factor of 10 or so.
The PPS on my TBolt was also too short for a PC running Linux/ntpd to catch
it. (It
Just a follow-up on this.
Yesterday I received a Thunderbolt from fluke.l,
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=290322053618
This worked straight away and has cured the 50 minute drift
cycle. I'm getting a standard deviation of pulse interval of
about 0.25uS, as measured against
Peter Vince wrote:
> I have just received an ebay notification of new
> items for sale by a "favourite seller" - list member
> Bob Mokai, aka fluke.l in China:
Thanks for the heads-up Peter. That makes three
recommendations I've had for this seller.
I expect I'll order one or two of these 'tim
On 2 July 2010 09:05, Paul Nicholson wrote:
...
> Well now, this sure looks to me like a GPS effect.
> I think I'd better order another GPS, a different type,
> maybe a GlobalSat MR-350P, or something, for comparison.
> Recommendations?
Hello again Paul,
I have just received an ebay notifi
n
> Subject: [time-nuts] Long period variation of GPS PPS timing?
> To: time-nuts@febo.com
> Message-ID: <4c2c6ab4.9030...@abelian.org>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> I am using the PPS from a Garmin GPS16 to timestamp a VLF
> signal receiv
Hi
For the $50 to $100 cost it's tough to beat a Thunderbolt. It's overkill for
the application, but easy to find.
Bob
On Jul 2, 2010, at 6:45 AM, Paul Nicholson wrote:
> David Partridge wrote:
> > Is this a timing GPS receiver, or a generic fast start
> > navigation receiver?
>
> Just an o
David Partridge wrote:
> Is this a timing GPS receiver, or a generic fast start
> navigation receiver?
Just an ordinary nav GPS, Garmin model GPS16HVS intended
I think for marine/vehicle applications. Spec says cold
boot 45 seconds, warm boot (position unchanged) 38 seconds.
Measured warm boot i
2010 09:05
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Long period variation of GPS PPS timing?
This morning I waited for the VLF timing signals to settle into their steady
daytime phase - still showing the slow cycle of phase variation.
Then I power-cycled th
This morning I waited for the VLF timing signals to settle
into their steady daytime phase - still showing the slow
cycle of phase variation.
Then I power-cycled the GPS, leaving everything else running.
During the 25 seconds it takes the GPS to begin sending PPS
again, my software continues to
David C. Partridge"
To: "'Discussion of precise time and frequency measurement'"
Sent: Thursday, July 01, 2010 8:38 PM
Subject: Re: [time-nuts] Long period variation of GPS PPS timing?
Sawtooth variation in pps time - that does sound a bit familiar in
referenc
Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Long period variation of GPS PPS timing?
FYI, some time has elapsed with one soundcard instead of two and the slow cycle
is still present, same period, and the phase of the slow cycle did not make a
step change.
Now
time-nuts-boun...@febo.com wrote on 07/01/2010 02:01:25 PM:
> From:
>
> Paul Nicholson
>
> To:
>
> Discussion of precise time and frequency measurement
>
> Date:
>
> 07/01/2010 02:02 PM
>
> Subject:
>
> Re: [time-nuts] Long period variati
FYI, some time has elapsed with one soundcard instead
of two and the slow cycle is still present, same period,
and the phase of the slow cycle did not make a step
change.
Now I must take a careful look at how the centroid is
being determined, the resampling, RC temperature, etc.
Maybe the 'sawtoo
Matthew Kaufman wrote:
> What is the soundcard sample rate? This feels like an artifact
> of sample phase vs. pulse phase to me.
There are actually two soundcards, running at
192003.8285 and
192002.1638
samples/sec, varying a little. They are on different computers.
One takes an East/West si
time-nuts-boun...@febo.com wrote on 07/01/2010 12:06:54 PM:
> From:
>
> Paul Nicholson
>
> To:
>
> Discussion of precise time and frequency measurement
>
> Date:
>
> 07/01/2010 12:08 PM
>
> Subject:
>
> Re: [time-nuts] Long period variati
What is the soundcard sample rate? This feels like an artifact of
sample phase vs. pulse phase to me.
Matthew Kaufman
(Sent from my iPhone)
On Jul 1, 2010, at 9:06 AM, Paul Nicholson wrote:
Thanks all for the various replies, on and off list.
John WA4WDL wrote:
> Perhaps you should use on
y measurement
> Subject: Re: [time-nuts] Long period variation of GPS PPS timing?
>
> Thanks all for the various replies, on and off list.
>
> John WA4WDL wrote:
> > Perhaps you should use only the leading edges for the
> > pulse-to-pulse interval measurement.
>
>
Bob Camp wrote:
> I'd put a heat gun on your R/C networks and see what happens...
Yes, good point. The RCs must have a temperature coefficient,
maybe not something I can neglect, I'd better look at that.
In fact, now that I know it's not inherent to GPS, I have quite
a long list of things to e
Paul Nicholson
Sent: Thursday, July 01, 2010 12:07 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Long period variation of GPS PPS timing?
Thanks all for the various replies, on and off list.
John WA4WDL wrote:
> Perhaps you should use only the leading edges
Thanks all for the various replies, on and off list.
John WA4WDL wrote:
> Perhaps you should use only the leading edges for the
> pulse-to-pulse interval measurement.
Yes, I'm just using the leading edge, turning it into a pulse
using a couple of RC networks, slowing the rise and fall enough
to
hen moving.
Rob Kimberley
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of jmfranke
Sent: 01 July 2010 2:51 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] Long period variation of GPS PPS timing?
I am not sure about the Garmin GPS16,
: "Paul Nicholson"
Sent: Thursday, July 01, 2010 6:15 AM
To:
Subject: [time-nuts] Long period variation of GPS PPS timing?
I am using the PPS from a Garmin GPS16 to timestamp a VLF
signal received directly via a PC soundcard. Signal into one
channel, PPS into the other.
Using puls
Hello!
If considered useful, I can send you the yesterday record of my GPS
TBolt #2 against DCF77, which apparently doesn't show any periodic
phase variation. The VLF receiver is a Tracor 599K and the chart
span is 10 uS. If there was such a variation it should be clearly
visible.
Antonio
CT1TE
Hi Paul,
Others on this list will reply more authoritatively, but I don't
believe that cyclic variability is GPS - I've not noticed such a thing
on any of the systems I monitor. Can you carefully monitor
temperature and PSU voltage, and maybe find a correlation there?
Peter
__
I am using the PPS from a Garmin GPS16 to timestamp a VLF
signal received directly via a PC soundcard. Signal into one
channel, PPS into the other.
Using pulse centroid timing, I'm seeing about 0.5uS jitter of
the pulse-to-pulse interval, and an exponential moving average
with time constant 100
26 matches
Mail list logo
