On 10/13/2012 8:30 AM, Adrian wrote:
12V for the oven because inside the outer oven lives a 10811-60158 ( see
http://www.realhamradio.com/GPS-oven-journey.htm ) that, as by the specs
sheet, is specified 12 to 30 V DC, 11 W max. at turn on (mine draws some
9 W), and Steady state power drops to
These ideas are "interesting". AFAIK, there is very little
chance of running out of Cs in many years, long past the
time when something else in the tube will have reached its
end of life. Where did this idea come from? Certainly, not
anyone working at HP, Agilent or Symmetricom. A LONG time
ag
On 10/4/2012 9:45 AM, Tom Van Baak wrote:
Bob,
Right, not good. There should be a fault message associated with it. Check the
internal log.
OTOH, to conserve cesium, I've heard that some people run 5071A in standby mode
most of the time and only turn on the cesium for a fraction of an hour
Sorry I have never seen those statistics.
Rick
On 9/30/2012 2:23 PM, ewkeh...@aol.com wrote:
Rick
I have some 10811's all below 1 E-12 in the 1 to 100 sec. range, a few as
low as 4 E-13 at 10 seconds. How low have you seen, I have the opportunity
to test 40+ units and hope to find a few even b
On 9/30/2012 2:20 PM, Magnus Danielson wrote:
With two such offset 10811s you could use DMTD methods or for that
matter cross-correlation phase noise measures to more directly measure
the units. That way you would have avoided the "golden unit" issue,
since the phase noise of those would aver
all 10811s or would there be
as much unit to unit variation as there is for aging and Allan Deviation?
Ed
On 9/30/2012 11:03 AM, Richard (Rick) Karlquist wrote:
I recently modified an old 10811 to bring out the crystal
leads on miniature coax (instead of having them connect
to the oscilla
al and the loading of the
bridge oscillator.
Bob
On Sep 29, 2012, at 11:46 PM, Richard (Rick) Karlquist
wrote:
The E1938A uses a crystal that is basically the same as
the 10811 crystal except that it is in a reduced height
package. However the phase noise is not as good as a
10811 due to broadban
The E1938A uses a crystal that is basically the same as
the 10811 crystal except that it is in a reduced height
package. However the phase noise is not as good as a
10811 due to broadband noise in the automatic frequency
control circuit. By the time I discovered this, it
was too late to try to f
On 9/16/2012 12:03 PM, Gerhard Hoffmann wrote:
Am 20.07.2012 00:57, schrieb Richard (Rick) Karlquist:
A fast comparator seems like a good idea, and it
is simple, however it is actually the last thing
you want to use. High thermal sensitivity and high jitter.
Rick
On 7/19/2012 1:35 PM, Dan
ntors, and I have attended many FCS's. I
don't know how you prove to the Wiki police that
there is no paper predating EerNisse's paper.
Maybe there is a patent on it.
On 9/11/2012 2:22 PM, jim s wrote:
On 9/11/2012 10:01 AM, Richard (Rick) Karlquist wrote:
The SC cut crystal is g
The SC cut crystal is generally credited to Jack Kusters
(of HP) and Errol Ernisse. The story was something like
Errol proposed the concept and Jack actually made the
first one, which was quite non-trivial.
Jack used to joke that "SC" stood for Santa
Clara. (Jack and I worked for the old HP Sant
On 8/27/2012 11:45 PM, WB6BNQ wrote:
A microprocessor controlled XO is a non oven crystal oscillator system that has
additional computational control providing a bit more than just mere passive
temperature compensation. The additional computational capability deals with
having coefficients of
On 7/22/2012 2:41 PM, Bob Camp wrote:
Hi
The feedback inverter is indeed a problem with fast logic, just bias it to mid
point off the supply instead.
1. Do not use CMOS inverters. Even though so much has been published on
using these in linear mode by
adding a feedback resistor, they c
A fast comparator seems like a good idea, and it
is simple, however it is actually the last thing
you want to use. High thermal sensitivity and high jitter.
Rick
On 7/19/2012 1:35 PM, Dan Kemppainen wrote:
Or use a fast comparator such as an ADCMP600 series. Much lower delays,
and faster risin
On 9/22/2011 5:17 PM, ws at Yahoo wrote:
Within minutes the frequency changed more than the spec
For humidity to get thru something like that it takes weeks or more it
does it at all.
That fast of reaction, Sure sounds like some other effect like blowing a
little air on the case or loading the
On 9/22/2011 4:17 PM, Chuck Harris wrote:
You had a leak. If epoxy was really as bad as you indicate,
it would not be usable for holding pressure, or mild vacuum,
and yet it is. Somehow, someway you left a big hole in the
bucket.
-Chuck Harris
Soda pop bottles hold pressure for years. Vacuu
This article was in the PTTI proceedings around 1990.
Highly recommended.
Rick Karlquist
On 9/9/2011 6:58 AM, Jim Lux wrote:
On 9/9/11 6:37 AM, ehydra wrote:
Hi Bruce -
Do you have a reference to read on for this?
I imagine that's the standard cascade of limiters used in zero crossing
detec
And you are being redundant, by saying "SI system" which is like
saying International System System. Also see "PIN number" :-)
Rick
On 4/5/2011 2:22 PM, ehydra wrote:
For me it looks like this guy hates SI system. There are many out there.
How cares?
The problems arise if systems get mixed up
Higher voltage on the EFC corresponds to higher frequency.
Rick Karlquist
N6RK
E1938A designer
On 3/11/2011 9:00 AM, Allwright, Mark wrote:
Hi.
I am looking for the slope of the EFC voltage for a HP E1938A (positive or
negative). I found the other parameters I am looking for but this one s
What you need is the AD9913. It has a programmable modulus.
Now you're not stuck with 2^32. You can pick any convenient
value.
Rick Karlquist N6RK
On 1/25/2011 5:37 AM, Ulrich Bangert wrote:
Gentlemen,
the pros and cons of DDS chips and how to improve them have been discussed
here from time
On 1/22/2011 6:04 AM, Michael Baker wrote:
I have a need for a 110 MHz VCXO in a 1.8GHz to 7.5GHz
tracking generator I am building for my Tek 494 spectrum
analyzer. I bought a pair of Silicon Labs 110 MHz VCXO
chips for less than $25 for the pair from Cramer
Distributors.
This is a popular FAQ that Cs engineers hear.
The correct answer (at least for HP/Agilent CBTs)
is that there is plenty of Cs in the tube, and
they don't fail because they ran out of Cs. Something
else will always wear out first.
Regarding the general idea of rebuilding CBT's:
a used CBT is so
On 1/7/2011 5:22 PM, Tom Van Baak wrote:
Has anyone experimented with the amount of insulation on a
10544 or 10811 oscillator? They are meant to run hot by
design and I worry that adding any insulation, or too much
insulation, will either cause over-heating or limit the ability
of the oven cont
Clarification of my previous posting:
The IF output of the ASK-1 should be pins 2 and 5,
not pins 4 and 5.
The LO input of the ASK-1 is pins 1 and 3.
The RF input of the ASK-1 is pins 4 and 6.
This is not obvious from the data sheet.
You can wire these two ports in series any
way you like, act
On 12/21/2010 10:11 PM, Bernd Neubig wrote:
Hi Rick,
I have a problem to imagine how you connect the LO and RF port of a mixer in
series and drive it (the IF port?) with a ... sine wave.
Can you send me a sketch of this arrangement please?
Tnx a lot!
Best regards
Bernd Neubig DK1AG
Good que
I used to be in the synthesizer business (Zeta Labs)
in a previous life. I learned to ask the customers:
what you are trying to accomplish as the end goal,
before tackling a messy problem like multiplying by
7. Maybe you don't need to multiply by 7, but we
can't tell from your question.
Rick Ka
Several issues here:
1. Making a precision crystal like the 10811 one is very involved.
It cannot simply be rescaled to a different frequency. It represents
a whole new design. This is not like ordering custom crystals for
your 2 way radio (back in the day).
2. The 10.23 MHz crystals I am go
A friendly warning about crystal filters. Crystals, whether
used in an oscillator or filter, have intrinsic phase noise.
You cannot improve the phase noise of a crystal oscillator
with a crystal filter unless the filter crystals have lower
phase noise than the oscillator crystals. In general, po
Someone was asking about SC cut crystals to play with.
I have a few dozen 10.23 MHz SC cut crystals that are
interchangeable with 10811 10 MHz crystals, except for
the frequency difference. They were made for a GPS
version of the 10811 that never saw the light of day.
Any interest in these?
Rick
I would call this gadget more of a time interval analyzer
than a clock.
Rick Karlquist N6RK
On 10/29/2010 1:01 PM, JULIAN TOPOLSKI wrote:
Researchers at Fermilab are building a “holometer” so they can disprove
everything you thought you knew about the universe. More specifically, they are
tr
I think you should probably be fine at 18V. The oven will run down
to at least 15V and maybe 12V.
Rick Karlquist N6RK
On 10/19/2010 5:27 AM, ewkeh...@aol.com wrote:
I plan on replacing the Xtal Osc. of my HP 5062C with a HP 10811 since I
have a few ones with AV less than 1E-12 from 1 to 100
On 10/12/2010 8:11 AM, gsteinb...@aol.com wrote:
Just a quick note...
HP was quite proud that scales for their precision meters were individually
produced
for each movement on a custom made servo controlled photographic calibrator.
An archive might be nice but won't provide the meter
Regardless of isolated anecdotal data on one oscillator, it
is probably not advisable to change the set point. The majority
of 10811 crystals do NOT have a turnover, only a region of
low tempco around 82 degrees.
Instead of that, change the circuit to B-mode and optimize
the heat between the two
On 9/30/2010 12:43 PM, Alan Melia wrote:
Mark to my inexpert eye that doesnt look like a very good overtone
oscillator but I appreciate that it is slimmed down to keep the weight and
size down, I can see why it is touchy. There is nothing to make the
oscillator degenerate at the crystal fundame
A couple of disclaimers here:
1. Leeson's oscillator model was mentioned. That
doesn't apply much to crystal oscillators. The close
in noise will be limited by the intrinsic noise of
the crystal and the far out noise will be limited by
the buffer amplifier. Leeson's model never comes
into pla
ulm...@vaxman.de wrote:
blinked. This problem was eventually solved by driving the LED with a discrete
transistor instead of a free 74AC14 gate and decoupling this driver with an
RC-combination.
CMOS logic gates have a totem pole output that is famous for "overlap"
where both transistors on b
Hal Murray wrote:
Several years ago, I found a web site for a commercial place that made them
for museums. (I forget why I was looking for that sort of stuff.) You might
find interesting stuff/ideas via google but I didn't find a similar site with
a bit of searching.
The Museum of Scie
Samuel DEMEULEMEESTER wrote:
Right now, the performance is really good up to 3.5 GHz :
50 MHz : -7 dB
100 MHZ : -15 dB
250 MHz : -26 dB
500 MHz : -30 dB
1 GHZ : -32 dB
2 GHz : -32 dB
3 GHz : -30 dB
The real deal on the performance of prescalers is the ability to count
noisy sources. If y
We have a bunch of sweepers at work, and many of the them have
died and can't be fixed. The only way they can be repaired is
to cannibalize one to fix another, assuming they don't have
the same bad module. We have given away an 8510 to a school
and have others gathering dust.
Rick
jimlux wrote
What the 10811 production line did was to compare two 10811's
to each other by driving a high level mixer. Anzac AM-123
amplifiers were used to increase the output level of the 10811's.
You can homebrew the AM-123 if you read the patent and can
get a 2N5109/2N5943 type of transistor. Amplify the
Samuel DEMEULEMEESTER wrote:
Hi Rick,
My goal is not to design a killer prescaler useable for all applications,
but just to get the same specs than the original HP/Agilent prescaler board,
and why not a bit better. The original HP board is a very basic design :
4-stage of MMIC and a good-old M
Bob Camp wrote:
Hi
Tough to believe that HP worried a lot about SKU inflation back when they
did the 5370 :)
I'm assuming that the 5370 was a Santa Clara design. That would put the
counter designers down the hall from the oscillator factory. Unlikely that
there was a communications gap ab
It is entirely possible that a 10544 could have excellent aging and beat
a 10811. The SC cut doesn't improve aging. The other "disadvantages"
of the 10544 in terms of electronics also don't affect aging. The
main advantage of the 10811 is that it is much better from a cold start
in an instrumen
For a simple crystal oscillator the two word answer might be "Leeson's model". That of course is a cop out since it clearly defines multiple things that contribute to phase noise.
Bob
And Leeson's model is basically the same as Edson's model, circa 1950
(Edson: Vacuum Tube Oscillators)
Don Collie jnr wrote:
I`m not sure that questions like these is welcome on this list, but here goes anyway :
1/ What are the the 10 sources of the most constant [invariant] frequencies
known to man, in order of decreacing constancy? Four immediately come to mind.
I vaguely remember reading t
Bruce Griffiths wrote:
Only if the noise figure of the following amplifier is 4dB or so.
With no extra amplification is used one only needs a signal level of
+1dBm to achieve a phase noise floor of -178dBc/Hz if the output is
extracted through the crystal in such a way that the thermal noise
When the 5071A product line was sold to Symmetricom ~4 years ago,
the production manager and his team of 15 moved with the product.
The manager left Symmetricom a few years ago, and recently most
of the rest of the team left Symmetricom. The 5071A will now
be made on the east coast at the facilit
David C. Partridge wrote:
Cough - the rubidium clock or oscillator does have an intrinsic frequency,
which is the rubidium hyperfine transition of 6 834 682 610.904 324 Hz, it's
just that the frequency generated by the transition in question isn't used
to DEFINE the second, so by definition, it
paul swed wrote:
Or simply fuse externally with a reasonable fuse holder and fuse.
No, you don't understand. It is a THERMAL fuse. It must be IN
the oven to do any good. There is definitely no excess room
inside of the 10811 to add a fuse holder.
Rick Karlquist N6RK
_
Maybe! But for the sake of clarity: I have been asking how HP/Symmetricom
manage to handle the regulation loop appearantly WITHOUT time constant
adaption/switching and with a fixed time constant that seems to be much too
high to start with for a cold OCXO.
Best regards
Ulrich Bangert
One
The XT-Nano-XXL looks very interesting, and the price is good.
With these kinds of hardware devices, the question always
arises as to what to use on the other end to talk to the
device. I see that ak-nord has a virtual com port driver,
which many vendors have. It would also be interesting to
se
Lux, Jim (337C) wrote:
microwave frequency down to where it can be compared with the reference. You
can do a straight divider, but then, the number of divide ratios is limited,
because fast dividers tend to be powers of two, or, at best, small integers.
Generally true, but Centellax has a di
Dave M wrote:
I haven't been able to find schematics for the Extron DA, but according to
the author's discussion, it seems to be very similar to the DA circuit
schematics at http://www.ko4bb.com/~bruce/IsolationAmplifiers.html. I
haven't had time to reverse engineer the circuit in my Extron
You really need to mix down to a low frequency beat note as in the
HP5390 system. There is a huge increase in sensitivity by doing
that. It is not difficult to make a mixer circuit.
Rick Karlquist N6RK
John Green wrote:
I've been hanging around and reading long enough to understand that when
Bob Camp wrote:
Hi
I think that if you dig into it, you will find that there is a polarized
light process to orient the blank before the base plate is applied.
Unfortunately for the discussion at hand, the direction of maximum G
sensitivity is still random relative to the mount.
Bob
KB8T
Jim Flanagan wrote:
after warmup, I need to tweak the temp for a freq MIN. Whereas, for an SC
cut xtal osc we would be looking for a freq MAX. For both xtal cuts the
turning
point is typically set for somewhere in the 75 - 85 C range. I see
Jim
jf...@tampabay.rr.com
The majority of 10
Mark Sims wrote:
I have done quite a bit of work replacing fans in old equipment with modern
fans.
I have never seen a case where replacing a hurricane level fan with a
whisper
quiet fan made any real difference in the cooling inside the unit...
typically
one sees less than +/- 5C dif
Bruce Griffiths wrote:
> Some ECL devices have jitter specs in the 100 to 200fsec range.
> see:
> http://www.onsemi.com
>
This is misleading. While it is true that they have this
low jitter at multi-Gb/s rates, the jitter is much greater
than this at lower clock rates. At 10 MHz, ECL devices
J. L. Trantham wrote:
> Thanks for the info.
>
> My plan is to develop a stable GPS disciplined reference suitable for use as
> a reference for Microwave work in the 10 GHz range that can be used in
> portable locations with relatively quick start up.
>
> Perhaps the 1938 would be better in th
J. L. Trantham wrote:
> I, too, snagged one of these since it has the reputation of being the
> ultimate achievement of crystal oscillator technology with the goal of
Thanks, we thought it was pretty good :-)
>
> Toward that end, since it takes a few minutes for the 1938 to 'lock', is
> there
wje wrote:
> Fluke.l (China) was selling a number of 1938's on Ebay. I snagged one
> just to have a piece of HP history.
> It works just fine, but I've noticed something a little strange.
>
> Comparing the 1938 to both my cesium and GPS standards, there's a
> distinct periodic 1ns phase shift ev
I would like to add some perspective to this discussion.
The 10811 oscillator simply uses a plain vanilla Pierce
circuit configured so that one terminal of the crystal
is at ground. The base emitter capacitor is replaced
by a mode suppression network to force operation to the
correct overtone and
Going back to Agilent's origins at HP, AFAIK, only Hewlett and Packard
ever had traditional "offices" with walls to the ceiling and doors.
Their offices are preserved in the condition they were in when
H & P left the company. Employees can visit these offices, which
are like a museum.
In practice
Trivia: The engineer who designed that chip for HP 35 years ago
has the cubicle next to me at Agilent Labs! It was considered
very advanced at the time.
Rick Karlquist N6RK
(employed by Agilent Technologies)
Murray Greenman wrote:
> I've obtained a faulty HP 8640B signal generator, and have det
John Miles wrote:
>>> Modern ECL parts aren't necessarily that bad compared to the old MECL
>>> stuff.
>> My experience goes all the way back to the MECL 1000 series that was
>> discontinued 30 years ago. I designed many synthesizers around them
>> for Zeta Labs. Every newer family of ECL line
Moderate humidity changes caused frequency shifts on the
order of parts in 10^9. With the environmental chamber
on full throttle, I saw parts in 10^8.
The E1938A has an unmeasurable humidity coefficient, even
unsealed.
Rick Karlquist N6RK
Jim Lux wrote:
> Some mention has been made recently of
Didier Juges wrote:
> The designers of the HP E1938 (which never went to full production) went
> through pains to try and keep the gradient evenly distributed precisely for
> that reason. My guess is that it you take the cover out from the E1938, you
> will find a perfectly symmetrical layout ar
Well, the good news is (if you buy one of these) is that the worst
that can happen is that you unwrap all that 2nd oven junk and
you are left with a 10811 for $50. I remember when they were
designing that double oven 10811. There are so many things
wrong with the design that I wouldn't know where
Early GPS receivers used a 10.23 MHz time base.
Probably related to 2^10-1.
Some GPS manufacturers approached HP about making
a 10811 on 10.23 MHz. There is a circuit modification
for 10.23 MHz and some crystals were made (I
have some somewhere). However, I don't believe
any 10.23 MHz 10811's wer
Now we have gotten to the crux of the matter. You have
to decide on one of two approaches:
1. The zero crossing is what is to be measured.
In this case, you have to retain all harmonics. You cannot
use most of the traditional frequency counting techniques.
You must sample the zero crossing dire
This is a complicated question. First of all, there is definitely
no crystal filter involved. However, the multiplier can have its
own phase noise due to either the amplifier or the SRD. There can
also be AM to PM conversion and vice versa. I have found the
technique of multiplying a source to
> I have some Wenzel OCXOs that hit 5E-13 for a 1 second tau. No Rb or Cs
> or Z3801 that I have running get that good at 1 sec tau! Over 10,000
> is a different matter, however.
>
>
> -Brian, WA1ZMS
That level of performance is about average for an HP 10811 and some are
considerably better
The diode limiter is to protect the C channel
from getting burned out due to connecting a
transmitter to it, etc. You don't need the
limiter if you aren't worried about this.
The detector gates off the counter when there
is insufficient signal to count reliably.
The detector is imperfect, and the
The relationship between phase noise and Allan variance is
a complex one and was described in papers at FCS in 1976
and 1978 by my previous manager Mike Fischer (then of HP).
I think these papers come closest to answering your question.
Rick Karlquist
Jeff Mock wrote:
> This is a half-baked idea
I was the project manager and chief EE on the HP5334B
project. The 5334A had a C channel using an HP made
divide by 10 prescaler that had a factory cost of ~$100.
In the 5334B, I replaced this with the Fujitsu MB506
divide by 8 prescaler, which cost something like $2.
The firmware was changed slig
I have been told the rotated cut is incompatible
with etching, due to anisotropy.
Rick Karlquist N6RK
Jim Miller wrote:
> In my web travels so far including the NIST papers I've yet to run across a
> crystal fabricated as both an SC cut and inverted mesa.
>
> Are these two properties incompatib
"doomday machine" just refers to the ultimate
performance design. Len was a perfectionist.
Rick
Rex wrote:
> Rick Karlquist wrote:
>> I wish Len Cutler were
>> still around to tell about it. He proudly keep a 107 prototype
>> in his office. Len couldn't bring himself to design anything that wa
The long term aging rate is due entirely to the crystal,
for all practical purposes, for any well designed oscillator
circuit (or even a mediocre design). The aging of the
crystal is basically not predictable. It's like the famous saying
by J P Morgan when asked what the stock market will do:
"It
Tom Van Baak wrote:
> Rick,
>
> For these experiments did you remove the 10811 guts from the
> outer case? I realize the case is not sealed, but the air gap is
> very small; how could humidity get inside so rapidly?
>
> Did you look into /why/ the 10811 was humidity sensitive? The
> resonator
At the beginning of the E1938A project, I did a bunch of
characterization of 10811 oscillators. At the Santa Clara
Division, we had first class environmental test chambers
with heating, cooling, humidification, de-humidification,
and nitrogen purge. The nitrogen was also available for
fast coolin
Modern counters have "interpolators" (now called "time to
digital converters") that can measure
fractions of a cycle. Even the old Agilent 53132,
designed 15 years ago, measures any frequency to 12
significant figures in one second. For example, it will display
10 MHz to .1 Hz using a 1 secon
See:
http://www.karlquist.com/FCS95.pdf
Or look at the 1995 FCS proceedings.
Rick Karlquist
John Ackermann N8UR wrote:
> Anders Time said the following on 01/25/2008 07:23 AM:
>> What is the best way to generate a very stable 10.001MHz(low E-13 or
>> -110dBc/1Hz) to be to do high resolution het
I forgot to mention that the crystals for the E1938A had to
be calibrated for series resonance at 10 MHz.
Rick Karlquist N6RK
Didier Juges wrote:
> I think the main difference between parallel and series resonance is that in
> parallel resonance mode, the capacitance of the crystal holder and wi
> Not really, it's the circuit topology determines whether a parallel or
> series resonant crystal is used. Your circuit appears to be a variant
Just a comment about series vs parallel. The 10811 has a parallel
resonant circuit and the E1938A has a series resonant circuit.
The crystals used a
In the HP 10816 Rb frequency standard, we used a modified
10811 oscillator circuit. The oscillator and first buffer
amplifier transistor were the same, but the rest of the
buffer amplifier was replaced with a cascaded grounded
base buffer amplifier. We were able to get numbers comparable
to those
The SRD (step recovery diode) definitely degrades the phase
noise beyond 20 LOG N, according to Agilent engineers I have
talked to. They mentioned a number like -150 dBc/Hz or something.
Having said that, you also have to be very careful to design
the driver (especially with NLTL) or it will becom
From what I remember from the years I worked
on the 5071A is that the prognosis for CBT's
in long term storage is very poor. The Navy
had to scrap a bunch of them due to this problem.
I vaguely remember that the pressure got too high
for the ion pump to start. If it does start, I
think ion curre
We did a lot of characterization of crystal temp
vs freq in the E1938 development and never observed
any "aging" of these curves. Even on "green" crystals
with zero run time.
Rick Karlquist N6RK
Jeff Mock wrote:
> Thanks for the description, it is very interesting. I have a follow up
> questio
Coincidentally, I just learned today that the
E1983A is still being made by an OEM called
Scotts Valley Magnetics.
Rick Karlquist N6RK
Magnus Danielson wrote:
>
> Is the E1938 commercially available? If not, is there a followup?
>
> Cheers,
> Magnus
>
___
mpass other causes, how can I tell which
> is which? If phase noise or short term stability encompasses frequency
> jumps, how can I estimate the size of frequency jumps from those
> specifications?
>
> Didier
>
>> -Original Message-
>> From: [EMAIL PROTECT
lators are not that good, they just blow smoke really
> well.
>
> Didier KO4BB
>
>> -Original Message-
>> From: [EMAIL PROTECTED]
>> [mailto:[EMAIL PROTECTED] On Behalf Of Richard
>> (Rick) Karlquist
>> Sent: Friday, December 07, 2007 10:45 AM
>
Reminds me of the "SC" cut crystal.
It either means "Stress Compensated" or "Santa Clara",
where it was discovered :-)
The BVA has been around for a long time and you
would think that if there was really something to
it, everybody would be making them. Of course, they
are very difficult to make.
Why do you say there's room for another supplier?
5 years ago there were 3 suppliers, but Agilent
sold out to Symmetricom. What unmet need are you
proposing to fill?
What is the short term stability (sigma-sub-y-of-tau)
of your world class oscillator?
Rick Karlquist
(RF designer for the 5071A Ce
Don Collie wrote:
> Yes, you can cut a crystal to have an inversion temp at 25Deg C. [well
> certainly with an AT cut - I`m not sure about the SC cut.]
> Cheers,Don C.
The AT cut has an inflection point at 25 degrees C. You cannot
get a "turnover"
); SAEximRunCond expanded to false
Errors-To: [EMAIL PROTECTED] RETRY
Neon John wrote:
> Nah, not for this application. A Peltier module typically has a COP of 1.
> That is,
> it moves a watt of energy for each watt consumed. Thus, for each watt
> moved, two
> watts have to be dissipated t
); SAEximRunCond expanded to false
Errors-To: [EMAIL PROTECTED] RETRY
The 10811 has an ANALOG oven control loop. The gain is set
to be just below the oscillation point. This is due to the
stability limits dictated by the oven mass and (believe it
or not) the size of integrator capacitor that can
Neville Michie wrote:
> I am not trying to start an argument, but I would like to point out
> that PID controllers are only
> good at controlling a certain class of system.
> The thermal block controllers work well because of the dominant
> integrating effect of the block,
> the time delay
The labels may or may not be significant. If the frequency
is indeed -2.94 Hz at 2.5V EFC, you could probably get it back
to 10 MHz by increasing the EFC voltage. You can also decrease
the bridge capacitor to bring the frequency up if necessary.
The factory was supposed to choose the capacitor to
); SAEximRunCond expanded to false
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>> The simple answer, is it introduces another place for drift
>> to occur. If the power supply that provides the current to
>> create the C-field drifts with temperature, component aging,
>> power line voltages, phases of the
); SAEximRunCond expanded to false
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Hi Mike. I work for Agilent, and HP before that, at the
old Santa Clara Division, where the 10811 was made.
The 10811 Manual, published ~25 years ago, was never
in electronic form within the company. The 10811 was
only a relea
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