-Original Message-
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
> Sent: Thursday, February 14, 2008 7:04 PM
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] GPS Locked and Unlocked Performance
> Comparison
>
> Hello Didi
Hello Didier,
these Thaler references are quite low noise, 3uV <10Hz for the VRE305 is not
bad at all.
Do you know pricing for these in smaller qty?
BTW: I wish TI had added a good DAC to the MSC1210.
bye,
Said
In a message dated 2/14/2008 16:10:34 Pacific Standard Time, [EMAIL PROTEC
gt; From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
> Sent: Thursday, February 14, 2008 2:36 PM
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] GPS Locked and Unlocked Performance
> Comparison
>
> Hello Didier,
>
> maybe you are rig
Hello Didier,
maybe you are right, and that's not easy to find. I remember an app not from
LT (Jim WIlliams?) that discussed how to build a high-accuracy DC output DAC
using a Sigma Delta ADC and some logic etc.
Finding a 24 bit ADC is pretty easy, ADI, TI, Linear, Maxim etc seem to
offer
Hi,
I got also a 10KHz version fit on a CPLD as per request of
W7QX in early 2004 (for 100MHz etc) and later
for N1JEZ and G6GXK (this time having also 10MHz).
All is on my web pages since then
but only if you look in detail in the configuration
list files you find it...
I must rearrange my web la
D]
> Sent: Wednesday, February 13, 2008 4:11 PM
> To: [EMAIL PROTECTED]; time-nuts@febo.com
> Subject: Re: [time-nuts] GPS Locked and Unlocked Performance
> Comparison
>
> Hello Tom,
>
> Bruce mentioned there is a validity bit that can be checked
> for holdover. I wonder
From: Bruce Griffiths <[EMAIL PROTECTED]>
Subject: Re: [time-nuts] GPS Locked and Unlocked Performance Comparison
Date: Thu, 14 Feb 2008 14:14:37 +1300
Message-ID: <[EMAIL PROTECTED]>
> Magnus Danielson wrote:
> > From: [EMAIL PROTECTED]
> > Subject: Re: [time-nu
Magnus Danielson wrote:
> From: [EMAIL PROTECTED]
> Subject: Re: [time-nuts] GPS Locked and Unlocked Performance Comparison
> Date: Wed, 13 Feb 2008 19:43:58 EST
> Message-ID: <[EMAIL PROTECTED]>
>
>
>> Hi Magnus,
>>
>> yes filtering is easier at 10KH
[EMAIL PROTECTED] wrote:
> Hi Bruce,
>
> I wonder how the analog switches' tempco would affect the performance. They
> usually do have 10 - 100 Ohms series resistance if I remember correctly.
>
> The Temex OCXO is achieving STS of parts in E-013, it would be unfortunate
> to lose that perfo
From: [EMAIL PROTECTED]
Subject: Re: [time-nuts] GPS Locked and Unlocked Performance Comparison
Date: Wed, 13 Feb 2008 19:43:58 EST
Message-ID: <[EMAIL PROTECTED]>
> Hi Magnus,
>
> yes filtering is easier at 10KHz than 1Hz; I wonder how much of the 10KHz
> modulation signal
Hi Bruce,
I wonder how the analog switches' tempco would affect the performance. They
usually do have 10 - 100 Ohms series resistance if I remember correctly.
The Temex OCXO is achieving STS of parts in E-013, it would be unfortunate
to lose that performance due to external circuitry.
At
Hi Bruce,
there is an excellent paper in this months Evaluation Engineering on how to
get 3000dB EMI suppression out of an enclosure, and how small cracks, holes,
and crevices can degrade that performance to only 20dB or so:
_http://www.evaluationengineering.com/features/2008_February/0208_
Hi Magnus,
yes filtering is easier at 10KHz than 1Hz; I wonder how much of the 10KHz
modulation signal is getting through into the phase noise at the 10MHz output.
bye,
Said
In a message dated 2/13/2008 15:50:51 Pacific Standard Time,
[EMAIL PROTECTED] writes:
Indeed. While the time
From: [EMAIL PROTECTED]
Subject: Re: [time-nuts] GPS Locked and Unlocked Performance Comparison
Date: Wed, 13 Feb 2008 14:03:04 EST
Message-ID: <[EMAIL PROTECTED]>
Said,
> I wonder how the Miller unit would perform if the GPS is kept alive during
> holdover.
>
> If the Ju
PM
Subject: Re: [time-nuts] GPS Locked and Unlocked Performance Comparison
> David Welch wrote:
> > I was wondering with so many 10 mhz sources running.or even a single
cesium
> > and gps receiver running, as I have now..and the 10 mhz is also routed
to a
> > clock driver syst
David Welch wrote:
> I was wondering with so many 10 mhz sources running.or even a single cesium
> and gps receiver running, as I have now..and the 10 mhz is also routed to a
> clock driver system (leitch).I cannot receive 10mhz wwv broadcasts at all
> anytime,I am using a old radio shack sw radio
Tom Van Baak" <[EMAIL PROTECTED]>; "Discussion of precise time and
frequency measurement"
Sent: Wednesday, February 13, 2008 3:17 AM
Subject: Re: [time-nuts] GPS Locked and Unlocked Performance Comparison
> On Feb 13, 2008 1:03 AM, Tom Van Baak <[EMAIL PROTECTED]> wrote
[EMAIL PROTECTED] wrote:
> Hello Tom,
>
> Bruce mentioned there is a validity bit that can be checked for holdover. I
> wonder if a small micro can be used to hold the EFC voltage steady without
> much effort. Or maybe using Super-Caps in the loop filter?
>
> Or maybe use one of those new 2
Hi Tom,
I've done that inadvertently, using an M12+ with a totally (by several
miles) wrong hold position.
The results are astounding, the 1PPS goes completely nuts. Variations of
1000's of ns from 1PPS to the next. I would have expected the M12+ firmware to
be much smarter than that.
I
Hello Tom,
Bruce mentioned there is a validity bit that can be checked for holdover. I
wonder if a small micro can be used to hold the EFC voltage steady without
much effort. Or maybe using Super-Caps in the loop filter?
Or maybe use one of those new 24 bit Sigma-Delta ADC/DAC chips to capt
Tom Van Baak wrote:
> Said,
>
> All of these were run out-of-the-box. So yes, auto-survey.
>
> A fun experiment would be to set the position manually at different
> levels of [in]accuracy (say, +/- 1m, 3m, 10m, 30m, 100m) in
> lat, lon, and/or alt to graphically see the effect it makes on both
> 1P
- Original Message -
From: "Tom Van Baak" <[EMAIL PROTECTED]>
To: "Discussion of precise time and frequency measurement"
Sent: Thursday, February 14, 2008 8:53 AM
Subject: Re: [time-nuts] GPS Locked and Unlocked Performance
Comparison
> Hi Said,
>
>
two earlier simple
GPSDO prototypes from Miller and they each get better. I'll
have a better understanding when I make the measurements
Bruce suggested.
/tvb
- Original Message -
From: [EMAIL PROTECTED]
To: [EMAIL PROTECTED] ; time-nuts@febo.com
Sent: Wednesday, February 13, 2008 11:
> It's surprising what kind of performance can be achieved with the 10KHz
> locking the OCXO through an Exor gate. Then again that design
> get's to compare
> phase 10.000 times more often per second than all of the other
> 1PPS based PLL's
> :)
Which, as Bruce has noted, is not really an advanta
frequency stability.
/tvb
- Original Message -
From: [EMAIL PROTECTED]
To: time-nuts@febo.com ; [EMAIL PROTECTED]
Sent: Wednesday, February 13, 2008 10:50 AM
Subject: Re: [time-nuts] GPS Locked and Unlocked Performance Comparison
Hello Tom,
on the measurements did you use Auto
Hi Tom,
I wonder how the Miller unit would perform if the GPS is kept alive during
holdover.
If the Jupiter continues to generate the 10KHz and 1PPS from it's internal
TCXO even without GPS reception then I would expect the holdover performance
to degrade to that of the TCXO if the unit g
Hello Tom,
on the measurements did you use Auto Survey on these receivers? Or did you
give them a surveyed antenna position?
Even good GPS's I have seen have a 3-5 feet height error or so from Auto
Survey.
I wonder how much better these units would perform if they get a well
surveyed po
> How did you free-run the Miller design? The Jupiter receiver will give a PPS
> / 10KHz on power-up and keeps going regardless of satellite reception (at
> least mine does).
>
> Jason
Right. I think there are two ways to make clean free-run OCXO
measurements. One is to remove jumper JP1 which co
How did you free-run the Miller design? The Jupiter receiver will give a PPS
/ 10KHz on power-up and keeps going regardless of satellite reception (at
least mine does).
Jason
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Tom Van Baak wrote:
> Thanks to all of you so far that made comments on the
> GPSDO plots; I'll handle this one first.
>
Tom
> Both the Thunderbolt and Miller designs appear to measure at least 10x
> better than the most optimistic expectations.
>
>
> Bruce,
>
> Interesting thought. What calc
On Feb 13, 2008 1:03 AM, Tom Van Baak <[EMAIL PROTECTED]> wrote:
> To prevent, or at least detect, this effect I allow my 10 MHz
> house reference to drift off-frequency by quite a bit (last
> month it was 1.7e-12 off). That way there are no on-time
> or on-frequency sources near the test setup.
T
Thanks to all of you so far that made comments on the
GPSDO plots; I'll handle this one first.
> Tom
>
> Both the Thunderbolt and Miller designs appear to measure at least 10x
> better than the most optimistic expectations.
Bruce,
Interesting thought. What calculations did you use to set
your e
Hello Tom,
yikes, that does sound like a project indeed.
Long Term holdover design in a GPSDO is a real challenge, and even the older
specs (CDMA etc) are quite hard to achieve. This is where a Rubidium/Cs
really has a huge advantage over any Crystal design.
Another problem is the very la
Hi Kirby, Didier,
I agree, the short term performance (typically <200s or so) is almost
entirely determined by the OCXO performance itself.
That particular Miller OCXO is exceptionally good in terms of short term
stability, I am surprised that the OCXO can perform so well <1000s
free-runn
John Miles wrote:
>> To me, the interesting part is that both the Thunderbolt and the Miller
>> designs appear to degrade the performance of the OCXO in locked mode at
>> short Tau compared to unlocked. The Z3801 does very well < 300sec, but
>> degrades the ADEV at Tau farther out. The Fury does be
> To me, the interesting part is that both the Thunderbolt and the Miller
> designs appear to degrade the performance of the OCXO in locked mode at
> short Tau compared to unlocked. The Z3801 does very well < 300sec, but
> degrades the ADEV at Tau farther out. The Fury does best, never
> worse loc
> [mailto:[EMAIL PROTECTED] On Behalf Of Brian Kirby
> Sent: Tuesday, February 12, 2008 6:57 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] GPS Locked and Unlocked Performance
> Comparison
>
> Its interesting that the Miller/Jupiter d
Its interesting that the Miller/Jupiter design appears to outperform
everything except the Z3801, in the GPS locked modes. Maybe the KISS
principle at work.
[EMAIL PROTECTED] wrote:
> Hello Tom,
>
> excellent web-page! That looks like a lot of work was done.
>
> Would you have data for 24 h
t: Re: [time-nuts] GPS Locked and Unlocked Performance Comparison
Hello Tom,
excellent web-page! That looks like a lot of work was done.
Would you have data for 24 hour hold-over performance (86400s ADEV) for these
units?
thanks,
bye,
Said
In a message dated 2/11/2008 21:17:49 Pa
Hello Tom,
excellent web-page! That looks like a lot of work was done.
Would you have data for 24 hour hold-over performance (86400s ADEV) for
these units?
thanks,
bye,
Said
In a message dated 2/11/2008 21:17:49 Pacific Standard Time,
[EMAIL PROTECTED] writes:
Sifting through old da
Sifting through old data, in addition to recent measurements
made in the past few months, I have 4 very interesting plots
of GPSDO performance.
The goal was to see real-life plots of disciplining in action by
contrasting free (unlocked) vs. GPS-locked performance as
compared with my 10 MHz house r
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