Hi
I've used Z38xx with both the 3801 and 3805. It does a good job with both. Com
port setup is not automatic, so it's worth noting what serial setup (baud rate
etc) your unit needs.
Bob
On Jun 14, 2010, at 11:21 PM, Robert Benward wrote:
Hi Adrian,
I got it working the other day, thanks
Hi
With any phase lock system injection locking can indeed be a problem. Since
it's dependent both on frequency offset and phase angle, checking for it can be
tricky. I've seen an unfortunately large amount of data where injection locking
was the issue. There are a number of ways of checking
Bruce posted
But Adler's equation indicates that an oscillator is much more
susceptible to injection effects when the injected signal frequency is
very close to the oscillator frequency.
No argument,
BUT
The thing that you (and maybe Adler?) are missing is that effect goes away
when the two
Bob posted
Since it's dependent both on frequency offset and phase angle,
When there is no freq offset as in the wsTPLL and no changing of phase
angle,
I'm saying that injection locking no longer applies.
The thing that some may be missing is that the DUT Osc is cloned by the
reference Osc.
Warren wrote:
The thing that you (and maybe Adler?) are missing is that effect
goes away when the two frequencies ARE exactly the same.
I'm not talking close, I'm talking the exact same freq with phase
held in quadrature within single digit femtoseconds.
BIG difference, Once that is
Hi
If the two oscillators are locked by input to the EFC then the EFC voltage
will reproduce the phase / frequency of the DUT on the reference (they are
phase locked via the PLL).
If the two oscillators are locked by injection locking, small changes in the
EFC is no longer needed to keep them
Charles posted:
but the locked frequency will be different from both oscillators'
free-running frequency and
the EFC will not correctly indicate the test oscillator deviation
because it isn't the only control input in the system.
Good point and No argument (except for the deviation part)
I was surprised at the lack of it in this case. The 10811s are usually
fairly vulnerable to it; you certainly can't feed two of them into the mixer
on a 3048A without using isolation amps. But then, the loop BW is about a
thousand times wider in the TPLL than in a traditional loose-PLL phase
Bob posted:
If the two oscillators are locked by injection locking, small changes in the
EFC is no longer needed to keep them in phase / frequency alignment.
No disagreement
I guess the thing you may be missing is that there is so much gain and BW in
the TPLL EFC feedback loop that it
On 06/15/2010 03:28 PM, WarrenS wrote:
Bruce posted
But Adler's equation indicates that an oscillator is much more
susceptible to injection effects when the injected signal frequency is
very close to the oscillator frequency.
No argument,
BUT
The thing that you (and maybe Adler?) are missing
Bob posted
The injection lock gain rises at 1/f. At some point it's going to be
greater
than the gain through the EFC.
It would seem to me with that argument then nothing works, everything in the
universal will all be at the same frequency sooner or later.
fortunately
The PLL feedback gain
Magnus posted a bunch of good stuff,
Neither. It's a characteristic, it needs to be analyzed. If the DUT is
very sensitive, then additional care may be taken or maybe it just isn't
a very good solution.
We have little disagreements for the most part. Except maybe for if it
should be on 'the
Hi Warren,
On 06/15/2010 08:49 PM, WarrenS wrote:
Magnus posted a bunch of good stuff,
Neither. It's a characteristic, it needs to be analyzed. If the DUT is
very sensitive, then additional care may be taken or maybe it just isn't
a very good solution.
We have little disagreements for the
I promised myself I would not get into this any more, but here we go again...
WarrenS warrensjmail-...@yahoo.com wrote:
Charles posted:
but the locked frequency will be different from both oscillators'
free-running frequency and
the EFC will not correctly indicate the test oscillator
Hi
What is the configuration of your loop?
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of WarrenS
Sent: Tuesday, June 15, 2010 2:16 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Advantages
something we already know.
Didier
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Hi All,
How does one measure allan deviation? How does my computer measure the
stability of an oscillator? Is this coming from the Z3801A?
Thanks,
Bob
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It's been a long week and it's only Tuesday.
How can I prove that the A3 assembly is, in fact, phase modulating? In
other words, how can I prove that the 90 MHz signal from the A3 assembly to
J1 on the A4 assembly is phase modulated by the 137 Hz signal?
I have looked at the output of the A3
Joe,
You probably already have a phase detector capable of receiving your 90 MHz
signal: a good old broadcast FM receiver. Send the audio to the scope or
spectrum analyzer and you should see your 137Hz signal.
Didier
Sent from my BlackBerry Wireless thingy while I do
Robert Benward wrote:
Hi All,
How does one measure allan deviation? How does my computer measure the
stability of an oscillator? Is this coming from the Z3801A?
Thanks,
Bob
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Didier,
Thanks for the obvious solution. I was thinking about having to build a PLL
to track 90 MHz.
I'll give it a try. However, I wonder if it will be able to track such a
small deviation.
Joe
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]
Joe wrote:
Short of fabricating a 'phase detector', how can I prove that the A3 unit is
functioning in my 'problem child' unit. If I have to fabricate a 'phase
detector', how easy (or difficult) is that?
I have no idea how much phase modulation there is supposed to be. If
it is
Warren wrote:
Charles posted:
but the locked frequency will be different from both oscillators'
free-running frequency and
the EFC will not correctly indicate the test oscillator deviation
because it isn't the only control input in the system.
Good point and No argument (except for the
A VHF scanner might work as well. Use a scope on the audio. Alternately, I have purchased modulation analyzers real
cheap on EBAY.
Bob
- Original Message -
From: Didier Juges did...@cox.net
To: Time-Nuts time-nuts@febo.com
Sent: Tuesday, June 15, 2010 10:54 PM
Subject: Re:
Charles wrote:
I like Didier's suggestion of the FM tuner, but the phase modulation
will need to be substantial to detect it that way.
The deviation (modulation index) of a FM broadcast signal is very large, on
the order of +/-75KHz. The phase modulation will need to produce large
frequency
Charles Posted:
when dealing with measurement accuracy in the hundreds or tens of ppt,
this needs to be verified by
the results of carefully constructed experiments and hopefully also
supported by mathematical analysis.
No argument, on that part.
The carefully constructed experiments, that
On 06/16/2010 05:45 AM, Charles P. Steinmetz wrote:
Warren wrote:
Charles posted:
but the locked frequency will be different from both oscillators'
free-running frequency and
the EFC will not correctly indicate the test oscillator deviation
because it isn't the only control input in the
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