There is a reference to thermomechanical fatigue in Peltier devices with
respect to the effect of peltier device ripple current on the longevity
of the Peltier devices in the HP Journal article on an optical power meter.
Bruce
J. Forster wrote:
Peltier devices have been used as temperature
Magnus Danielson wrote:
Hi Steve,
On 09/05/2010 10:18 AM, Steve Rooke wrote:
On 5 September 2010 04:42, Rob Kimberleyr...@timing-consultants.com
wrote:
Just a thought, as you are in southern hemisphere, wouldn't you see
more
birds facing North?
Oops! I really meant North. Well spotted
Attila Kinali wrote:
On Wed, 01 Sep 2010 20:08:13 +
Poul-Henning Kampp...@phk.freebsd.dk wrote:
Yes, but what is the issues relating to sapphire loading? What's the
cost of the sapphire block and having it machined?
It is a saphire tube, a readily available, if not exactly
jimlux wrote:
Hal Murray wrote:
jim...@earthlink.net said:
The gas diffusing out through the drilled bolt.. sure it's drilled,
but the
conductance is so patheticaly low, you're literally waiting until
the gas
molecules happen to randomly bounce their wey up the hole.
I've never worked
Higher operating temperatures force the use of nickel alloy to replace
the silver palladium alloy traditionally used.
At higher operating temperatures (40c and above) its not possible to
turn off (without cooling it) the palladium leak.
The Russian masers use nickel or nickel alloy instead of
Reference for palladium-silver leak difficulty at high temperature.
http://tycho.usno.navy.mil/ptti/1988/Vol%2020_10.pdf
Bruce
Bruce Griffiths wrote:
Higher operating temperatures force the use of nickel alloy to replace
the silver palladium alloy traditionally used.
At higher operating
Poul-Henning Kamp wrote:
In message4c7f5918.7030...@xtra.co.nz, Bruce Griffiths writes:
Indicates that the operating pressure at the hydrogen dissociator is
likely to be a few Torr or so.
The pressure is basically: As low as possible in order to minimize
hydrogen collisions (other
Bruce Griffiths wrote:
Poul-Henning Kamp wrote:
In message4c7f5918.7030...@xtra.co.nz, Bruce Griffiths writes:
Indicates that the operating pressure at the hydrogen dissociator is
likely to be a few Torr or so.
The pressure is basically: As low as possible in order to minimize
hydrogen
Magnus Danielson wrote:
On 09/01/2010 09:39 PM, Poul-Henning Kamp wrote:
In message24c547b54ea34a69bacc4f823bb40...@pc52, Tom Van Baak
writes:
I found the original copies of both EFOS manuals, along with
a few photos. See:
http://www.leapsecond.com/museum/efos/
Interesting.
Page 4/3
of
fused silica is low so is the dielectric constant so the reduction in
cavity volume is relatively small.
The reduced Q of a dielectric loaded cavity may also be an issue in the
absence of cryogenic cavity cooling.
Bruce
Poul-Henning Kamp wrote:
In message4c7eb534.2040...@xtra.co.nz, Bruce
PTFE wall storage bulb wall coatings haven't been used for some decades,
FEP (or the Russian fluoropolymer ) is better in that a smoother coat is
achievable see:
http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2doc=GetTRDoc.pdfAD=ADA509340
http://www.spectratime.com/product_downloads/PTTI_FCS_2005.pdf
ewkeh...@aol.com wrote:
Any links to reading material, would be nice to learn what they did to get
a small package and how small is it?
Bert Kehren
In a message dated 8/29/2010 2:03:34 P.M. Eastern Daylight Time,
http://tycho.usno.navy.mil/ptti/ptti2002/paper14.pdf
Bruce Griffiths wrote:
http://www.spectratime.com/product_downloads/PTTI_FCS_2005.pdf
ewkeh...@aol.com wrote:
Any links to reading material, would be nice to learn what they did
to get
a small package and how small is it?
Bert Kehren
:51 AM, Bruce Griffiths wrote:
So everything above (and an AD797 and likely an OP-37) will do better than 2 nV / Hz into
1K Hz. That would let you check oscillators in the below -170, but not below
-180 range. You might or might
...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Bruce Griffiths
Sent: Tuesday, August 24, 2010 3:25 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Phase noise measurement (was - no subject)
Bob Camp wrote:
Hi
CHOP
Being able
The link isnt particularly useful as guests cant view the attachments
and registration is disabled
Bruce
dk...@arcor.de wrote:
Wenzel Audio Amp referred to in this email. Perfect! I drive with it a
3561A and a 7L5! Works for me. The only problem is getting any more
2SK369.
Any
from the servo integrator.
Bruce
Bruce Griffiths wrote:
The link isnt particularly useful as guests cant view the attachments
and registration is disabled
Bruce
dk...@arcor.de wrote:
Wenzel Audio Amp referred to in this email. Perfect! I drive with it a
3561A and a 7L5! Works for me
noise should be
even lower whilst the high frequency noise will be comparable/
If the feedback resistor values are reduced perhaps 3 @SK369BLs will
suffice.
Even lower flicker noise should be achievable if IF9030s are substituted
for the 2SK369s.
Bruce
Bruce Griffiths wrote:
http
The Wenzel Audio amp is a little noisier than it need be and it has a
poor PSRR, so that a very low noise power supply with low ripple is
essential.
Its not too hard to improve the PSRR and the input noise of such a
current feedback amplifier.
There are JFETS (IF9030) with similar noise
ewkeh...@aol.com wrote:
Thanks Bert
In a message dated 8/21/2010 11:43:53 A.M. Eastern Daylight Time,
dk...@arcor.de writes:
Wenzel Audio Amp referred to in this email. Perfect! I drive with it a
3561A and a 7L5! Works for me. The only problem is getting any more
2SK369.
Any
Poul-Henning Kamp wrote:
In message7c37.12cdef25.39a12...@aol.com, ewkeh...@aol.com writes:
I am not seeing it, what should I use to measure it 3561 and 7 spec
analyzer do not show it?
It is probably the 3561 not the 70k that has the best chance.
I am not aware of the precise
J.D. Bakker wrote:
At 23:49 +1200 14-08-2010, Bruce Griffiths wrote:
J.D. Bakker wrote:
At 19:01 +1200 14-08-2010, Bruce Griffiths wrote:
J.D. Bakker wrote:
However the ultimate test (other than breadboarding it) is to
actually simulate the sampling process and look at the deviation
The TDEV plot for the OCXO in question which can be derived from its
ADEV plot is perhaps a useful guide to the expected jitter when
measuring a particular time interval.
For long time intervals the phase noise much closer to the carrier than
5Hz will tend to dominate.
Bruce
Bob Camp wrote:
Attila Kinali wrote:
On Sun, 15 Aug 2010 14:59:43 +1200
Bruce Griffithsbruce.griffi...@xtra.co.nz wrote:
Mea Culpa.
Below is a link to the paper using SAW filters to achieve a sub ps time
interval interpolator noise:
http://cddis.gsfc.nasa.gov/lw16/docs/papers/las_4_Prochazka_p.pdf
And
J.D. Bakker wrote:
At 08:30 +1200 14-08-2010, Bruce Griffiths wrote:
J.D. Bakker wrote:
4) If the ADC(s) have a sufficiently wide full power bandwidth then
one could just sample a pair of quadrature phased 250kHz sinewaves.
As someone who's used to thinking in I/Q I must say I've always
J.D. Bakker wrote:
At 19:01 +1200 14-08-2010, Bruce Griffiths wrote:
J.D. Bakker wrote:
At 08:30 +1200 14-08-2010, Bruce Griffiths wrote:
Using a synchroniser allows the TAC output range to be combined
with the coarse timestamp derived by sampling a counter clocked by
the same clock
A method that measures the phase of a damped LC circuit oscillatory
transient triggered by the event to be timestamped:
http://risorse.dei.polimi.it/digital/products/2010/High frequency,high
time resolution time-to-digital converter employing passive resonating
circuits.pdf
Mea Culpa.
Below is a link to the paper using SAW filters to achieve a sub ps time
interval interpolator noise:
http://cddis.gsfc.nasa.gov/lw16/docs/papers/las_4_Prochazka_p.pdf
And the associated presentation:
http://cddis.gsfc.nasa.gov/lw16/docs/presentations/las_4_Prochazka.pdf
Bruce
An ACAM GP2 evaluation board is available here:
http://shop.omegacs.net/
However an ACAM GP1 would probably be a better fit in a DMTD with a beat
frequency of 10Hz or more as the GP1 has a measurement range of 200ms.
Bruce
Stanley Reynolds wrote:
Thanks for looking at my data that was what
Bruce Griffiths wrote:
An ACAM GP2 evaluation board is available here:
http://shop.omegacs.net/
Ignore this link as I omitted to read the fine print
However an ACAM GP1 would probably be a better fit in a DMTD with a
beat frequency of 10Hz or more as the GP1 has a measurement range
with a conventional 2 stage synchroniser clocked
at 2MHz) this would be the simplest solution in that it only requires a
single resistor and a single capacitor.
Bruce
Bruce Griffiths wrote:
Yes, with a 2MSPS ADC and 1-2us transition times one gets 2-4 samples
during the transition.
Worst case with a 1us
http://www.cordellaudio.com/papers/thd_analyzer.pdf
Lester Veenstra wrote:
Dick:
I, for one, would be interested in knowing more about Bob Cordell's
state-variable low-distortion oscillator. Do you soft copy details or a
pointer to a source?
Thanks, 73
Les
Lester B Veenstra
Some options:
1) Use a 74AHC05 for Q1 and Q2.
2) Switch the current source at the emitter node and only turn on the
current source when charging the capacitor.
This will increase the available TAC output voltage range and/or improve
the linearity by eliminating the diode.
However the
, reset switches etc are required.
With a 2MSPS sample rate a low pass filter output transition time of
1-2us should suffice (provided the ADC has a sufficiently large large
signal bandwidth).
Bruce
Bruce Griffiths wrote:
Some options:
1) Use a 74AHC05 for Q1 and Q2.
2) Switch the current source
switches etc are required.
With a 2MSPS sample rate a low pass filter output transition time of 1-2us
should suffice (provided the ADC has a sufficiently large large signal
bandwidth).
Bruce
Bruce Griffiths wrote:
Some options:
1) Use a 74AHC05 for Q1 and Q2.
2) Switch the current source
Advisable given the required mass will probably be in the 10-100 ton range.
Bruce
J. L. Trantham, M. D. wrote:
Personally, I would get out of the way. : )
Joe
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
Behalf Of Ian Sheffield
Sent:
amplifier is one option for
the noninverting amplifier.
The noninverting amplifier may also have higher supply rails should this
be useful/necessary.
Bruce
Bruce Griffiths wrote:
A high voltage opamp (or a low voltage opamp with a discrete output
stage with a voltage gain of at least 2) with -3V
J. Forster wrote:
You are picking very unimportant nits.
If there were a small noise spike from the opamp, it'd goose the pendulum
a tiny amount. That would be corrected on the next swing.
Heuristic analysis of this type is counter productive.
You are turning a trip to the corner store into
Bruce Griffiths
J. Forster wrote:
You are picking very unimportant nits.
If there were a small noise spike from the opamp, it'd goose the
pendulum
a tiny amount. That would be corrected on the next swing.
Heuristic analysis of this type is counter productive.
You
...
Don
Bruce Griffiths
No protection against external shorts or other undesired events.
Extensive analog filtering to avoid creating an effective radiator of
noise may also be necessary.
Simple analog techniques are probably simpler/cheaper once the necessary
filtering and protection are included
A high voltage opamp (or a low voltage opamp with a discrete output
stage with a voltage gain of at least 2) with -3V and + 30V supplies is
perhaps the simplest method.
The opamp merely senses the current flowing in a current sensing
resistor and regulates this voltage drop to equal the output
The 60mA load current would be problematic for most common opamps
without an output buffer stage.
High voltage opamps are relatively rare.
Bruce
J. Forster wrote:
Since it's inside a closed loop, the design is uncritical.
One option is a high voltage Op-Amp with +/- 25 to 30 VDC supplies.
A high voltage opamp (or a low voltage opamp with a discrete output
stage with a voltage gain of at least 2) with -3V and + 30V supplies is
perhaps the simplest method.
The opamp merely senses the current flowing in a current sensing
resistor and regulates this voltage drop to equal the output
J. Forster wrote:
OK. You know better.
BTW, op-amp noise is essentially irrelevant in this application, and the
C's across the FB resistors limit slew rates so there is no significant
dI/dt to cause voltage spikes.
Noise is never irrelevant.
You havent shown that its insignificant either.
Henry Hallam wrote:
Dear time nuts,
Background:
I have built a GPS receiver based around the SE4120L front end IC [1].
I used a KT3225 TCXO [2] at 16.3676MHz driving the front end through
a 10nF series capacitor as in the example circuit in [1]. Inside the
front end, this oscillator is
The GPS receiver chip actually specifies that a clipped sinewave should
be used.
Presumably this is necessary to limit the harmonic contents.
In which case low pass filtering the CMOS outputs may be necessary.
The 74AHC04 or equivalent may be a better choice as its ground and Vcc
bounce is
Henry Hallam wrote:
On Wed, Aug 4, 2010 at 1:50 PM, Bruce Griffiths
bruce.griffi...@xtra.co.nz wrote:
The TCXO output waveform is presumably a clipped sinewave as required by the
SE4120L?
I posted the waveform at
http://www.pericynthion.org/stuff/KT3225_500mV_per_div.jpg
Does
the cheap
TCXO's put out.
Bob
On Aug 4, 2010, at 6:42 PM, Bruce Griffiths wrote:
The GPS receiver chip actually specifies that a clipped sinewave should be used.
Presumably this is necessary to limit the harmonic contents.
In which case low pass filtering the CMOS outputs may be necessary
Bruce Griffiths wrote:
In which case a linear distribution amplifier is probably required.
With only a ~3V supply available, options for the distribution
amplifier topology are somewhat limited.
In principle you could use an emitter follower driving 4 other emitter
followers with a resistor
Griffithsbruce.griffi...@xtra.co.nz
Subject: Re: [time-nuts] Buffer / distribution amplifier for TCXO
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Message-ID:4c59e433.6000...@xtra.co.nz
Content-Type: text/plain; charset=iso-8859-1; Format=flowed
Bruce Griffiths wrote:
In which
You can't predict the settling time of an opamp from its slew rate or
its gain-bandwidth product.
The TS272 datasheet has no settling time spec whatsoever.
In this case, since there is no spec it needs to be measured.
Opamps with 2 or more cascaded gain stages like these are notorious for
poor
Instead of copying the Shera controller albeit with higher resolution
its probably more cost effective to choose a microprocessor with built
in time stamping capability.
The PIC24FJ128GA for example allows 30ns timestamping resolution via its
external timer capture inputs.
Other microprocessors
ewkeh...@aol.com wrote:
One more comment $ 40 would cover every thing including PC board, May go up
to 50 depending what D/A you use. Bert
In a message dated 7/28/2010 4:47:46 P.M. Eastern Daylight Time,
p...@phk.freebsd.dk writes:
In message4c5092fa.2030...@xtra.co.nz, Bruce Griffiths
Hal Murray wrote:
There is another way to compare two frequencies, relevant when they are
very close together. I divide a reference down to 100KHz and use it to clock
a phase detector made of a pair of D flip flops. The unknown (divided to
100KHz) is fed into the circuit and an output
Luis Cupido wrote:
MTI 230-0546-A
Is the pinout similar to the other 230 series OCXOs?:
http://www.mti-milliren.com/pdfs/230.pdf
Bruce
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To unsubscribe, go to
Chris
All the details are in the article:
http://www.edn.com/contents/images/6607197.pdf
However it would be best to read the article posted by Bob Camp first:
Bruce
Chris Stake wrote:
Hi Bruce,
This sounds like a promising idea, please could you expand on the
synchronous filter technique?
Here's a link to a pdf version of the synchronously filtered low ripple
pwm dac:
http://www.edn.com/contents/images/6553625.pdf
Bruce
Bruce Griffiths wrote:
Chris
All the details are in the article:
http://www.edn.com/contents/images/6607197.pdf
However it would be best to read the article
Attila Kinali wrote:
Moin,
On Sat, 26 Jun 2010 21:14:02 EDT
ewkeh...@aol.com wrote:
What you want is basically a Shera Board. That design has been around for
quite some time and has served me very well.
Yes. The Shera Board and similar designs serve as an example for me.
I
The problem is that the gain and offset of the 2 DACs changes with time
and temperature so that the required corrections also change.
Ideally an autocalibration technique would be used to dynamically track
such changes.
Since changes in the coarse DAC are only required infrequently and the
Attila Kinali wrote:
On Tue, 29 Jun 2010 21:32:10 +1200
Bruce Griffithsbruce.griffi...@xtra.co.nz wrote:
Its possible to build a 24 bit resolution D/A using a synchronously
filtered PWM circuit.
A pair of PWM outputs and a few relatively low precision resistors and
capacitors together
...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Bruce Griffiths
Sent: Tuesday, June 29, 2010 4:07 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] yet another GPSDO design, or so
Attila Kinali wrote:
On Tue, 29 Jun 2010 21:32:10 +1200
Bruce
Hal Murray wrote:
bruce.griffi...@xtra.co.nz said:
Its possible to build a 24 bit resolution D/A using a synchronously
filtered PWM circuit. A pair of PWM outputs and a few relatively low
precision resistors and capacitors together with a low noise low drift
reference are required. The
WarrenS wrote:
Long explanations, cause I try to explain, the best I can, when I say
something is WRONG or misleading
Magnus Posted:
EFC linearity will remain an issue for analog oscillators.
The oscillator gain will differ depending on offset voltage and
temperature.
TRUE it is an issue,
Disadvantages of the TPLL Method
Bruce Griffiths bruce.griffiths at xtra.co.nz
WarrenS wrote:
Long explanations, cause I try to explain, the best I can, when I say
something is WRONG or misleading
Magnus Posted:
EFC linearity will remain an issue for analog oscillators.
The oscillator gain will differ
WarrenS wrote:
subject: Advantages Disadvantages of the TPLL Method.
Here is a new and unique Idea that may be useful for many.
Rather than focusing on what some members may or may not already know,
or how good or bad one specific working BB configuration is.
How about focusing on what the
Magnus Danielson wrote:
On 06/12/2010 11:29 PM, Bruce Griffiths wrote:
WarrenS wrote:
subject: Advantages Disadvantages of the TPLL Method.
Here is a new and unique Idea that may be useful for many.
Rather than focusing on what some members may or may not already know,
or how good or bad one
that someone would add the advantages and
disadvantages to, so that any non relevant stuff could be easily seen
and removed or moved to a third list, It would all become much clearer.
ws
Magnus Danielson wrote:
On 06/12/2010 11:29 PM, Bruce Griffiths wrote:
WarrenS wrote
disadvantages like not working
so good with a CS or Rb standard.
If one has more time than money, there are ways around that.
ws
***
Bruce Griffiths bruce.griffiths at xtra.co.nz
Sun Jun 13 01:25:13 UTC 2010
Another disadvantage of the Tight PLL system that only applies to
multichannel
Tom Van Baak wrote:
Beside the general theoretical considerations as of what answer is
more acceptable (sincerely I agree so far) and what method could be
used to solve the matter, can anybody out there point me please to
any article on actual measurements of the variation rate of the
Wrong again.
The integration/averaging referred to occurs when one counts the output
transitions of the VFC for a fixed time interval.
This process needs to be replicated using the sampled EFC data if one is
to measure ADEV.
Bruce
Steve Rooke wrote:
I think I have found the source of the
Richard H McCorkle wrote:
Time-Nuts,
There has been much discussion on this list about methods
of measuring short-term stability. I wanted to make the
list aware of a new paper describing a small DMTD system.
The system was developed by William Riley, author of
STABLE32, and is described in
Steve Rooke wrote:
On 5 June 2010 19:07, Bruce Griffithsbruce.griffi...@xtra.co.nz wrote:
Wrong again.
No, I'm not wrong Bruce.
Your contribution is largely irrelevant to the original discussion.
The effect of the PLL itself is (or should be) well understood.
However various
Robert Benward wrote:
Joe,
Thank you for your inputs! The Z3815A I suspect is low voltage
If and only if a ~24-48V supply is considered low voltage.
The 10MHz outputs level is only around +4dBm though there are 4 10MHz
outputs.
, it has a large PC card/motherboard type of connector with a
Steve Rooke wrote:
On 4 June 2010 08:32, Charles P. Steinmetz
charles_steinm...@lavabit.com wrote:
If I may be allowed to summarize, it appears that Warren and Bruce agree
that integration is necessary to produce true ADEV results. Warren asserts
that the low-pass filtering his method
WarrenS wrote:
Bruce posted
The RC filter doesn't accurately integrate the frequency difference
over time interval Tau0.
For you to even state that means you still have NO idea what I'm
doing, It is getting sort of sad.
Correct the RC filter is not an integrator, it is used for the
Steve Rooke wrote:
On 3 June 2010 15:46, Bruce Griffithsbruce.griffi...@xtra.co.nz wrote:
WarrenS wrote:
As Bruce says It remains a mystery to him why this works.
It doesnt, it only appears to in a very restricted set of circumstances.
Bruce, I don't understand you,
of time.
Which is your way of saying that you don't understand the alternative
more accurate methods and won't consider them.
ws
***
Bruce
- Original Message - From: Bruce Griffiths
bruce.griffi...@xtra.co.nz
To: Discussion of precise time and frequency measurement
WarrenS wrote:
Bruce Posted
Rectangular integration isn't particularly accurate or efficient, better
techniques exist.
True, but in this case it is the easiest and at these speeds, efficiency is not
a big concern, It is made up for with faster oversampling.
and it is obvious so
accurate methods and won't consider them.
ws
***
Bruce
- Original Message - From: Bruce Griffiths
bruce.griffiths at xtra.co.nz
To: Discussion of precise time and frequency measurement
time-nuts at febo.com
Sent: Thursday, June 03, 2010 12:27 AM
Subject: Re: [time
Steve Rooke wrote:
Bruce,
On 3 June 2010 19:27, Bruce Griffithsbruce.griffi...@xtra.co.nz wrote:
Bruce, I don't understand you, when presented with visual evidence
that this method works you still deny it.
What visual evidence??
There is no proof that the technique works well in
John Miles wrote:
For those following this strange and wonderful saga:
http://www.ke5fx.com/tpll.htm
-- john, KE5FX
___
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and
WarrenS wrote:
As Bruce says It remains a mystery to him why this works.
It doesnt, it only appears to in a very restricted set of circumstances.
Not one of my best skills, but I'll try to explain it once again.
Now that they see it works, maybe someone else will be able to put this into
John Miles wrote:
The integration secret (which is no secret to anyone but
Bruce) is to analog filter, Oversample, then average the
Frequency data at a rate much faster than the tau0 data rate.
Which again is misleading as you specify neither the averaging method
nor
Steve Rooke wrote:
On 28 May 2010 07:42, Bruce Griffithsbruce.griffi...@xtra.co.nz wrote:
Steve Rooke wrote:
On 28 May 2010 04:40, David Martindaledave.martind...@gmail.comwrote:
Hmm. From here in Vancouver Canada, the name resolves to the same
address,
pings fail,
Ulrich
Close in spurs generated by the synthesiser may also be problematic.
One feature being that the spur levels will depend (in a complex way) on
the synthesiser output frequency.
One of the first problems to solve is making the close in spurs
sufficiently low.
Another problem is to
Didier Juges wrote:
Bill, I think you got it backwards. +/- 12V is typical for RS-232, 0/+5V is
for RS-422 and RS-485.
No RS-232 receiver should be damaged with +/- 12V or even +/- 15V because
that is their normal operating voltage.
Also, RS-422 and RS-485 have something like 25V common mode
WarrenS wrote:
Bruce
Good, It does seem like we are finally making some good progress.
You now seem to acknowledge that my tester could work if I integrate.
You now seem to acknowledge that I am integrating by using a filter.
In a sampled data system integration is equivalent to a filter but
As long as one is aware that your method (as implemented by you) doesn't
actually measure Allan variance, it may be useful for comparing the
relative stability some sources for small Tau (unfortunately the range
of Tau for which the method may produce useful results depends on the
phase noise
Warren
So you now actually integrate/average the frequency over the sampling
interval (Tau) after rejecting the need to do this for months?
Bruce
WarrenS wrote:
Bruce
Before we go around again and discuses what my simple tester can and
can not do and why,
It would be helpful if you would
You cannot approximate the sinc function frequency response of an ideal
integrator with an arbitrary low pass filter.
Your scheme will tend to misbehave (in that it will produce anomalous
ADEV estimates) when flicker phase noise is significant.
You actually need to use an analog low pass
The results have so far only been shown to be useful when white phase
noise dominates.
When the phase noise is white almost anything can be made to produce a
result that differs from ADEV by at scale factor.
In practice its sometimes difficult to know over what range of Tau that
the phase
Spreadsheets can be a snare and a delusion if not carefully applied with
full recognition of their limitations.
Unfortunately the divergent nature of flicker phase noise etc doesn't
become evident until one processes a very large number of samples.
1000 samples is never enough as many tests and
Warren
Calculating an integral using a sampled data system when the Nyquist
criterion is met is exactly equivalent to filtering albeit using just
the right coefficients.
Using rectangular approximation to the integral of the underlying
continuous function is also equivalent to a filter albeit
Hal Murray wrote:
bruce.griffi...@xtra.co.nz said:
If there is no electronic tuning available one can use a DDS based
synthesiser to produce a corrected output frequency. However close in spurs
will be problematic unless one use a couple of simple mix and divide stages
or resorts to a
Bob Camp wrote:
Hi
A coupe of issues with mechanical servo tuning:
1) It wears out the tuning capacitor pretty fast. They are designed for a
limited number of adjustments. They loosen up with a lot of tuning and this
degrades their stability.
2) It would be much easier to tear apart the
If there is no electronic tuning available one can use a DDS based
synthesiser to produce a corrected output frequency.
However close in spurs will be problematic unless one use a couple of
simple mix and divide stages or resorts to a Diophantine synthesiser
using phase noise truncation spur
There has been some work done on the effect of finite correlation
between oscillator outputs.
In some cases allowing a finite correlation coefficient improves the N
cornered hat ADEV estimates.
In most cases the oscillators being compared share the same ambient
environment and thus may exhibit
Leigh L. Klotz, Jr WA5ZNU wrote:
On 03/24/2010 03:18 PM, Magnus Danielson wrote:
Fellow time-nuts,
...
Second, anything I should keep in mind as I power one up?
...
Cheers,
Magnus
There's a bit of discussion in the archives about the need for a heat
sink, and also about the whether it's
b...@lysator.liu.se wrote:
Zealand is an island between Denmark and Sweden.
Was not aware of that. Lat/Lon?
Zeeland is a province of the Netherlands
Been there...
Bruce
--
Björn
The name New Zealand originates from the latter via Dutch Cartographers.
Upload it to the manuals section of Didier's site:
http://www.ko4bb.com/cgi-bin/manuals.pl
Bruce
Brian Kirby wrote:
The manual is about a megabyte - the list will not accept it.
ewkeh...@aol.com wrote:
Is there a way you can post it on time-nuts?
Thank you Bert Kehren
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