I have learned the hard way that the 4046 needs input signals whose
risetimes [and falltimes?] are not too long , and It`s probably best to use
the inhibit function, and avoid using the source follower. The output
resistance can then be absorbed into the first resistor of the loop filter,
On Monday 23 April 2007 03:56, Don Collie wrote:
The thing that puzzles me is: why is the plot of
VCO voltage versus time different when locking from below to locking from
the same initial frequency difference when locking from above. It`s a pity
you can`t predict PLL lockup
Hello all,
The recent talk about the ideal GPSDO has reminded this newbie of a
question I hope someone might be able to simply answer: we have a couple
of Rubidium GPSDOs which track in the long term, but their phase drifts
by several hundreds of nanoseconds with an irregular, but
Bob Paddock wrote:
On Monday 23 April 2007 03:56, Don Collie wrote:
The thing that puzzles me is: why is the plot of
VCO voltage versus time different when locking from below to locking from
the same initial frequency difference when locking from above. It`s a pity
you can`t predict
* The Vref output of most OCXO's is from a Zener diode inside the can.
These
typically have aging, thermal sensitivity and very poor voltage accuracy,
and there are much better monolithic high-precision, low-tempco voltage
reference available on the market now (Digikey etc). Depending
Tom
Attached images are drift plots for:
1) VRE430 reference utilising a buried zener.
2) LM199
3) LTZ1000
Bruce
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Question - does Vref drift matter for a GPSDO? It seems it is
either too low to be of concern or the effect of Vref drift is in
fact indistinguishable from OCXO frequency drift and is thus
transparently compensated by any 3rd order loop?
I don't know for sure, but is 1 ppm/day drift in Vref
Tom
Attached images are drift plots for:
1) VRE430 reference utilising a buried zener.
2) LM199
3) LTZ1000
Bruce
OK, thanks very much. What I read from the slopes in
those long-term plots are Vref drift rates on the order of:
-6 ppm / 1000 hours (= 2e-12/d)
-2 ppm / 1000 hours (=
Tom Van Baak wrote:
Can someone do a similar numerical analysis of these two
factors: tempco and noise? It's not that I don't believe you;
it's just that I'd rather see numbers and plots than words.
Tom
When the reference is temperature cycled hysteresis may be significant.
Hysteresis
Tom
Attached is some hysteresis and other data for various references.
NB take the claimed XFTE reference ADR293 drift figure with a large dose
of salt, its 2 orders of magnitude lower than ADI claim.
Bruce
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Hello Community,
some time ago there were several threads on this list concerning the
HP59309A HP-IB Digital Clock.
My own HP 59309A Digital Clock does not respond to the EXT FREQ STD
input,
so I want to try to check and fix this problem.
Does anybody know where to get a
Martin,
Stupid question. Is the front panel switch set to ext?
I have a manual. I'd be willing to scan it if I somone would be willing to
host it.
Norm
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On Apr 22, 2007, at 23:47, [EMAIL PROTECTED] wrote:
Hi Henk,
great to hear that you got a Wavecrest DTS-2075!! That machine can
detect
spurs that phase noise measurements are oblivious too. Spurs cause
nasty
deterministic jitter of course.
That DTS2075 is at my employers lab.
That
In a message dated 4/23/2007 06:05:12 Pacific Daylight Time,
[EMAIL PROTECTED] writes:
-6 ppm / 1000 hours (= 2e-12/d)
-2 ppm / 1000 hours (= 6e-13/d)
-2 ppm / 3000 hours (= 2e-13/d)
+6 ppm / 5 months (= 5e-13/d)
+10 ppm / 12 months (= 3e-13/d)
-1 ppm / 10 days (= 1e-12/d)
-1.5 ppm / 30
Can someone do a similar numerical analysis of these two
factors: tempco and noise? It's not that I don't believe you;
it's just that I'd rather see numbers and plots than words.
Tom attached plot of zener noise is also from Eickes 1964 paper.
Bandpass is a little unclear as its
In a message dated 4/23/2007 10:51:38 Pacific Daylight Time,
[EMAIL PROTECTED] writes:
Hi Henk,
The $900 unit on ebay was a DTS2070.
Yes, I have bought that unit for my home lab but it has not yet arrived.
Same OCXO as the DTS2075...
Attached is a PRS-10 phase noise plot I measured
I would like a copy of the manual also.
Could it be put it on the wiki?
--- Norman J McSweyn [EMAIL PROTECTED] wrote:
Martin,
Stupid question. Is the front panel switch set to
ext?
I have a manual. I'd be willing to scan it if I
somone would be willing to
host it.
Norm
that switch setting and that the inside switch is set to the freq of the
outside frequency. I am at work today but will check. also the internal
battery is 9v and a jumper is in place for operation. I added a 4volt
zenner to allow operation from my battery system (12v solar) to be plugged
On Apr 23, 2007, at 20:13, [EMAIL PROTECTED] wrote:
Your nice picture shows a -95dBc phase noise at 10Hz.
The SRS spec for PRS10 is -130dBc at 10Hz. Can you explain that
difference of 35dBc?
The X axis is labeled in exponential form by the TSC instrument, it's
actually -95dBc/Hz at 1Hz
In a message dated 4/23/2007 11:03:07 Pacific Daylight Time,
[EMAIL PROTECTED] writes:
So you can imagine that Vref noise on the order of 1e-12 might
just start being noticeable in the plot, meaning that if you want
short-term performance down in the low 12's and if you have
an OCXO that
In a message dated 4/23/2007 11:27:39 Pacific Daylight Time,
[EMAIL PROTECTED] writes:
I will zip and send off list.
Thanks!!
Do you have the Vectron OCXO specs?
No, but someone on this list mentioned some time ago that they sold
these
units to Vectron (Bruce?) and posted some
Hi Tom:
Appendix H of Linear App Note 86 A Standards Lab Grade 20-Bit DAC with
0.1ppm/C Drift on pdf page 43 describes the 1,000 X amplifier they used and
the need for an out of production analog scope with to see sub 1 uV noise as
well as the need for a totally shielded measurement system.
Norm I could use a copy of this manual also and would be willing to host.
Please let me know.
Joe
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Norman J McSweyn
Sent: Monday, April 23, 2007 12:23 PM
To: Discussion of precise time and frequency
Can anyone suggest a source for the TAPR GPS interface for the Oncore UT+?
Thanks!
Bob
WA7ZRX
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Gentlemen,
I'll get right on it. The large pages will have to be copied at a local
blueprint store.
Updates soon.
Norm n3ykf
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In the FWIW department, I now have an old Ricoh BW scanner that can handle up
to 11x17, and can generate PDF's. I've been using it for doing oversize
schematic pages from manuals.
Daun
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf
Of Norman J McSweyn
TIA Norm,
I'll be one of the many users to thank you for taking the trouble, even
while mine has been working fine so far...
Cheers,
Hans PA0LED
At 16:29 23-4-2007 -0400, you wrote:
Gentlemen,
I'll get right on it. The large pages will have to be copied at a local
blueprint store.
Updates
My 3458A can make measurements down to the 10nV level. At 7 1/2 digits it can
do 60 readings
a second. At 8 1/2 digits it slows down to 6 readings a second. The real
question is the frequency
of the noise. I have yet to interface it to HP-IB bus. I have several Z3801's I
could try it on.
Tom Van Baak wrote:
Also an idea - is there an easy way to artificially increase Vref
noise, by say 10x, so one could see if that change made any
measurable change in OCXO output ADEV or phase noise?
/tvb
Tom
1) Increase the cutoff frequency of any low pass filter used.
2) With a
Hi Colin:
That's one sweet meter. Years ago at work I used them and we had both flavors.
One used the old definition of the volt and the other used the new volt.
Although our cal lab was not good enough to calibrate them we could feed them
signals and measure their readings. They differed
Ladies and gentlemen:
The manual will be done this evening. (A big thank you to Colleen at the
blueprint place!) I will send this to whomever would like a copy.
Please drop me a note: normn3ykf AT stny.rr.com
It will be done in two hours or so. 2340 utc now.
Norm n3ykf
Tom Van Baak wrote:
Also an idea - is there an easy way to artificially increase Vref
noise, by say 10x, so one could see if that change made any
measurable change in OCXO output ADEV or phase noise?
/tvb
Tom
Another possibility is to use a low noise instrumentation amplifier with
a
You are welcome to upload it to my manuals page
http://www.ko4bb.com/ham_radio/Manuals
Upload instructions are at the top.
Didier
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Norman J McSweyn
Sent: Monday, April 23, 2007 12:23 PM
To: Discussion of precise time and
attachment did not make it, there it is:
http://www.ko4bb.com/ham_radio/Manuals/Tektronix -
7L5/Tek-7L5-PhaseNoise.png
Didier
Didier Juges wrote:
Tom Van Baak wrote:
Related - does anyone have equipment in your home/lab that
can directly measure, at uV or sub-uV levels, noise on the
Message: 9
Date: Mon, 23 Apr 2007 16:25:27 -0700
From: Brooke Clarke [EMAIL PROTECTED]
Subject: Re: [time-nuts] GPS: ADEV or MDEV? (Tom Van Baak)
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Message-ID: [EMAIL PROTECTED]
Content-Type: text/plain;
Palfreyman, Jim L wrote:
Folks,
The longest antenna I have for my GPSDO is 5m (it's a Trimble ACE III
inside). Is it possible to lengthen this just by adding an extension
cable (SMB female on one end and SMB male on the other)? I'd be
interested in adding another 5m.
I've not been able to
In a message dated 4/23/2007 18:54:54 Pacific Daylight Time,
[EMAIL PROTECTED] writes:
If an unheated reference exposed to wide ambient temperature swings is
used then hysteresis may be significant when the OCXO is continuously
powered.
The significance and magnitude of the effect
At 1:11 PM +1000 4/24/07, Palfreyman, Jim L wrote:
Folks,
The longest antenna I have for my GPSDO is 5m (it's a Trimble ACE III
inside). Is it possible to lengthen this just by adding an extension
cable (SMB female on one end and SMB male on the other)? I'd be
interested in adding another 5m.
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