, 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 if a small micro can be used to hold
the EFC
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
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
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[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 right, and that's not easy to find. I remember
an app
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
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 Didier,
these Thaler references are quite low noise
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
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.
Tom,
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 calculations
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.
[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 24 bit
]; Discussion of precise time and
frequency measurement time-nuts@febo.com
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:
To prevent, or at least detect, this effect
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 on
-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 system (leitch).I cannot receive 10mhz wwv broadcasts
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 Jupiter continues
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
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:
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 10KHz than 1Hz; I wonder how much of the 10KHz
modulation
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 is getting through
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
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