Discussion:
Improving ocxo temp control
(too old to reply)
Richard (Rick) Karlquist
2018-05-19 04:03:20 UTC
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Raw Message
In my experience, the oven temperature controller is rarely
the determining factor for static oven performance. This article
explains what the real determining factors are:

http://www.karlquist.com/oven.pdf

An analog oven temperature controller will be limited in
its dynamics by how much capacitance you are able to
design with. Digital controllers get around this as well
as having the capability of double integration for much
better transient response.

Rick

On 5/18/2018 11:03 AM, Gilles Clement wrote:
> Hi,
> I am trying to improve performance of an OCXO.
> Could you point me at a good design of a high resolution oven temperature controler please ? Preferably analog.
> Thx much,
> Gilles.
>
>
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>
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Club-Internet Clemgill
2018-05-21 16:23:23 UTC
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Thanks for your interesting replies.
What I am actually trying to do is the following:
I bough a small ocxo (size of half a ping-pong ball) that performs well (Abracon / AOCJY3_B 10Mhz)
Reaching about 5*10E-11 kind of MDEV at low point ("kind of"… because a I use an HP52132a as input to Timelab)
But it’s frequency is slowly drifting with time, with a quasi linear slope.
I wondered if placing it in a third ovenized enclosure could improve things.
I tried a few experiments but seems that the temp needs to be very accurately controlled.
Any similar experience ?
Could you suggest papers describing high performance analog or digital controllers ?
Thx,
Gilles.


> Le 19 mai 2018 à 16:09, Bob kb8tq <***@n1k.org> a écrit :
>
> Hi
>
> One key point about the need for “zero gradient”:
>
> Crystals and many other components are quite sensitive to thermal gradients. Very small
> fractions of a degree (as a gradient ) can have significant impact on the frequency of an
> oscillator.
>
> One of many “interesting things” about fiddling about OCXO’s.
>
> The equally frustrating thing about this is that unless you can tease kind paper authors
> into posting things ( thanks Rick !!) the papers are behind pay walls. I pretty much despise
> that practice. Referencing papers that send people off to spend money ….not so much.
>
> Bob
>
>> On May 19, 2018, at 12:03 AM, Richard (Rick) Karlquist <***@karlquist.com> wrote:
>>
>> In my experience, the oven temperature controller is rarely
>> the determining factor for static oven performance. This article
>> explains what the real determining factors are:
>>
>> http://www.karlquist.com/oven.pdf
>>
>> An analog oven temperature controller will be limited in
>> its dynamics by how much capacitance you are able to
>> design with. Digital controllers get around this as well
>> as having the capability of double integration for much
>> better transient response.
>>
>> Rick
>>
>> On 5/18/2018 11:03 AM, Gilles Clement wrote:
>>> Hi,
>>> I am trying to improve performance of an OCXO.
>>> Could you point me at a good design of a high resolution oven temperature controler please ? Preferably analog.
>>> Thx much,
>>> Gilles.
>>> _______________________________________________
>>> time-nuts mailing list -- time-***@febo.com
>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>> _______________________________________________
>> time-nuts mailing list -- time-***@febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.

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Bob kb8tq
2018-05-21 17:12:02 UTC
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Hi

There are a lot of reasons an OCXO drifts. Temperature control is rarely the issue.
More likely you are looking at the drift / wander characteristics of the crystal ( and
components) in the OCXO. The simple answer is to leave it on for a while ( like weeks)
to allow things to settle out a bit.

The paper that Rick tossed up last week is a pretty good one in terms of temperature
control issues in an OCXO and what the issues are.

This all assumes you are in a fairly benign environment. If you have lots of drafts, put a
cardboard box over the unit to shield it. If you room temperature is all over the place, then
there are a lot of ways to get to ~ 1 or 2C sort of stability in a lab. What you do depends
a *lot* on what your situation is.

=====

So, assuming you *do* want to improve the temperature control:

First you need to take out what’s in there now. If it’s wandering around get rid of it. This
involves tearing apart the OCXO.

Now take a look at Rick’s paper and redesign the thermal enclosure. Get the heater placement
and sensor placement right and feed that into a simple controller.

Run some tests over temperature and check out the data. It’s likely your first guess at things
is not going to be correct.

Try to optimize the heat sources and sensors and re-test the result. Everything interacts so
this is not a quick process.

Once you are reasonably happy with where things are, start looking at a more fancy controller.
A simple approach would be feeding thermistor voltage into some 24 bit ADC’s and then
processing the result with an MCU.

Ok so that’s all a bit much.

=====

What happens if you mess with the OCXO from the outside of the package?

You change the heat loss out of the package. This increases the thermal gain. ( less power
to increase the oven temperature by 1 C ). Assuming the original circuit was balanced
out, you have made things worse rather than better.

Ok so you do an enclosure with a fan it it so the heat loss doesn’t get less.

You now have more heat loss and the same issue applies. In addition the fan and it’s
nonsense probably haven’t done the poor little OCXO any good.

When one designs a double oven, the inner oven is optimized for performance *with*
the outer oven present. Equally, the outer oven is optimized for performance with the
heat load (and dynamics) of the inner oven.

=====

Assuming you still want to head down this road, temperature controllers are no different
than any control loop. The first place to start is a textbook on control loops and control
theory. The basics of what a loop does and the terminology are what you are after. Anything
advanced will assume you understand this part first.

Next up are temperature sensors. Simple answer here is that a glass bead thermistor is
the way to go. For heat, transistors are the normal go-to device. The controls loop takes
in the thermistor output and spits out a voltage to change the current through the transistor.

If you have the money for software licenses, the next stop is some good mechanical CAD
that will feed into thermal modeling. From that you can work out a proper heat flow and
gradient design. Assuming that is a bit to expensive, you are back to trial and error. There
are no “just duplicate this” designs that I know of.

Once you have the structure, sensors, heaters, and control you toss it into a temperature
test chamber. That may be something fancy or something you put together. You run the
gizmo over temperature and observe what it does. You then optimize the P,I,D coefficients
in your control loop. Indeed you may not have all of them or you may have an extra one.

=======

Of course one could simply shop for a $20 OCXO on eBay. Even if you have to buy a
dozen before you find a good one, it’s still cheaper / faster / easier / more likely to succeed
than all the nonsense above. If this is a commercial design for a product you are going
to sell, that does not work very well. The same fundamental answer applies. If you need
better performance, shop for a better oscillator.


Lots of fun !!!!



> On May 21, 2018, at 12:23 PM, Club-Internet Clemgill <***@club-internet.fr> wrote:
>
> Thanks for your interesting replies.
> What I am actually trying to do is the following:
> I bough a small ocxo (size of half a ping-pong ball) that performs well (Abracon / AOCJY3_B 10Mhz)
> Reaching about 5*10E-11 kind of MDEV at low point ("kind of"… because a I use an HP52132a as input to Timelab)
> But it’s frequency is slowly drifting with time, with a quasi linear slope.
> I wondered if placing it in a third ovenized enclosure could improve things.
> I tried a few experiments but seems that the temp needs to be very accurately controlled.
> Any similar experience ?
> Could you suggest papers describing high performance analog or digital controllers ?
> Thx,
> Gilles.
>
>
>> Le 19 mai 2018 à 16:09, Bob kb8tq <***@n1k.org> a écrit :
>>
>> Hi
>>
>> One key point about the need for “zero gradient”:
>>
>> Crystals and many other components are quite sensitive to thermal gradients. Very small
>> fractions of a degree (as a gradient ) can have significant impact on the frequency of an
>> oscillator.
>>
>> One of many “interesting things” about fiddling about OCXO’s.
>>
>> The equally frustrating thing about this is that unless you can tease kind paper authors
>> into posting things ( thanks Rick !!) the papers are behind pay walls. I pretty much despise
>> that practice. Referencing papers that send people off to spend money ….not so much.
>>
>> Bob
>>
>>> On May 19, 2018, at 12:03 AM, Richard (Rick) Karlquist <***@karlquist.com> wrote:
>>>
>>> In my experience, the oven temperature controller is rarely
>>> the determining factor for static oven performance. This article
>>> explains what the real determining factors are:
>>>
>>> http://www.karlquist.com/oven.pdf
>>>
>>> An analog oven temperature controller will be limited in
>>> its dynamics by how much capacitance you are able to
>>> design with. Digital controllers get around this as well
>>> as having the capability of double integration for much
>>> better transient response.
>>>
>>> Rick
>>>
>>> On 5/18/2018 11:03 AM, Gilles Clement wrote:
>>>> Hi,
>>>> I am trying to improve performance of an OCXO.
>>>> Could you point me at a good design of a high resolution oven temperature controler please ? Preferably analog.
>>>> Thx much,
>>>> Gilles.
>>>> _______________________________________________
>>>> time-nuts mailing list -- time-***@febo.com
>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>>> and follow the instructions there.
>>> _______________________________________________
>>> time-nuts mailing list -- time-***@febo.com
>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

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Azelio Boriani
2018-05-21 20:15:27 UTC
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Raw Message
First, be sure not to measure your HP52132A stability with the OCXO.
What is your reference source?

On Mon, May 21, 2018 at 7:12 PM, Bob kb8tq <***@n1k.org> wrote:
> Hi
>
> There are a lot of reasons an OCXO drifts. Temperature control is rarely the issue.
> More likely you are looking at the drift / wander characteristics of the crystal ( and
> components) in the OCXO. The simple answer is to leave it on for a while ( like weeks)
> to allow things to settle out a bit.
>
> The paper that Rick tossed up last week is a pretty good one in terms of temperature
> control issues in an OCXO and what the issues are.
>
> This all assumes you are in a fairly benign environment. If you have lots of drafts, put a
> cardboard box over the unit to shield it. If you room temperature is all over the place, then
> there are a lot of ways to get to ~ 1 or 2C sort of stability in a lab. What you do depends
> a *lot* on what your situation is.
>
> =====
>
> So, assuming you *do* want to improve the temperature control:
>
> First you need to take out what’s in there now. If it’s wandering around get rid of it. This
> involves tearing apart the OCXO.
>
> Now take a look at Rick’s paper and redesign the thermal enclosure. Get the heater placement
> and sensor placement right and feed that into a simple controller.
>
> Run some tests over temperature and check out the data. It’s likely your first guess at things
> is not going to be correct.
>
> Try to optimize the heat sources and sensors and re-test the result. Everything interacts so
> this is not a quick process.
>
> Once you are reasonably happy with where things are, start looking at a more fancy controller.
> A simple approach would be feeding thermistor voltage into some 24 bit ADC’s and then
> processing the result with an MCU.
>
> Ok so that’s all a bit much.
>
> =====
>
> What happens if you mess with the OCXO from the outside of the package?
>
> You change the heat loss out of the package. This increases the thermal gain. ( less power
> to increase the oven temperature by 1 C ). Assuming the original circuit was balanced
> out, you have made things worse rather than better.
>
> Ok so you do an enclosure with a fan it it so the heat loss doesn’t get less.
>
> You now have more heat loss and the same issue applies. In addition the fan and it’s
> nonsense probably haven’t done the poor little OCXO any good.
>
> When one designs a double oven, the inner oven is optimized for performance *with*
> the outer oven present. Equally, the outer oven is optimized for performance with the
> heat load (and dynamics) of the inner oven.
>
> =====
>
> Assuming you still want to head down this road, temperature controllers are no different
> than any control loop. The first place to start is a textbook on control loops and control
> theory. The basics of what a loop does and the terminology are what you are after. Anything
> advanced will assume you understand this part first.
>
> Next up are temperature sensors. Simple answer here is that a glass bead thermistor is
> the way to go. For heat, transistors are the normal go-to device. The controls loop takes
> in the thermistor output and spits out a voltage to change the current through the transistor.
>
> If you have the money for software licenses, the next stop is some good mechanical CAD
> that will feed into thermal modeling. From that you can work out a proper heat flow and
> gradient design. Assuming that is a bit to expensive, you are back to trial and error. There
> are no “just duplicate this” designs that I know of.
>
> Once you have the structure, sensors, heaters, and control you toss it into a temperature
> test chamber. That may be something fancy or something you put together. You run the
> gizmo over temperature and observe what it does. You then optimize the P,I,D coefficients
> in your control loop. Indeed you may not have all of them or you may have an extra one.
>
> =======
>
> Of course one could simply shop for a $20 OCXO on eBay. Even if you have to buy a
> dozen before you find a good one, it’s still cheaper / faster / easier / more likely to succeed
> than all the nonsense above. If this is a commercial design for a product you are going
> to sell, that does not work very well. The same fundamental answer applies. If you need
> better performance, shop for a better oscillator.
>
>
> Lots of fun !!!!
>
>
>
>> On May 21, 2018, at 12:23 PM, Club-Internet Clemgill <***@club-internet.fr> wrote:
>>
>> Thanks for your interesting replies.
>> What I am actually trying to do is the following:
>> I bough a small ocxo (size of half a ping-pong ball) that performs well (Abracon / AOCJY3_B 10Mhz)
>> Reaching about 5*10E-11 kind of MDEV at low point ("kind of"… because a I use an HP52132a as input to Timelab)
>> But it’s frequency is slowly drifting with time, with a quasi linear slope.
>> I wondered if placing it in a third ovenized enclosure could improve things.
>> I tried a few experiments but seems that the temp needs to be very accurately controlled.
>> Any similar experience ?
>> Could you suggest papers describing high performance analog or digital controllers ?
>> Thx,
>> Gilles.
>>
>>
>>> Le 19 mai 2018 à 16:09, Bob kb8tq <***@n1k.org> a écrit :
>>>
>>> Hi
>>>
>>> One key point about the need for “zero gradient”:
>>>
>>> Crystals and many other components are quite sensitive to thermal gradients. Very small
>>> fractions of a degree (as a gradient ) can have significant impact on the frequency of an
>>> oscillator.
>>>
>>> One of many “interesting things” about fiddling about OCXO’s.
>>>
>>> The equally frustrating thing about this is that unless you can tease kind paper authors
>>> into posting things ( thanks Rick !!) the papers are behind pay walls. I pretty much despise
>>> that practice. Referencing papers that send people off to spend money ….not so much.
>>>
>>> Bob
>>>
>>>> On May 19, 2018, at 12:03 AM, Richard (Rick) Karlquist <***@karlquist.com> wrote:
>>>>
>>>> In my experience, the oven temperature controller is rarely
>>>> the determining factor for static oven performance. This article
>>>> explains what the real determining factors are:
>>>>
>>>> http://www.karlquist.com/oven.pdf
>>>>
>>>> An analog oven temperature controller will be limited in
>>>> its dynamics by how much capacitance you are able to
>>>> design with. Digital controllers get around this as well
>>>> as having the capability of double integration for much
>>>> better transient response.
>>>>
>>>> Rick
>>>>
>>>> On 5/18/2018 11:03 AM, Gilles Clement wrote:
>>>>> Hi,
>>>>> I am trying to improve performance of an OCXO.
>>>>> Could you point me at a good design of a high resolution oven temperature controler please ? Preferably analog.
>>>>> Thx much,
>>>>> Gilles.
>>>>> _______________________________________________
>>>>> time-nuts mailing list -- time-***@febo.com
>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>>>> and follow the instructions there.
>>>> _______________________________________________
>>>> time-nuts mailing list -- time-***@febo.com
>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>>> and follow the instructions there.
>>
>> _______________________________________________
>> time-nuts mailing list -- time-***@febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
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Bill Hawkins
2018-05-19 03:20:13 UTC
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My experience with industrial temperature control says there is always a
time lag between applying power to the heater and raising the
temperature at the thermistor.

Because there is a lag, there is a gain beyond which the system
oscillates.

But I haven't read the non-referenced papers, so I could be wrong.

Bill Hawkins


-----Original Message-----
From: time-nuts [mailto:time-nuts-***@febo.com] On Behalf Of Bob
kb8tq
Sent: Friday, May 18, 2018 9:46 PM

Hi

There are a number of papers out and about about the limits on OCXO
performance.
The bottom line is that coming up with a high resolution control circuit
is the easy part of the task.

Simple answer to the question:

Set up a thermistor bridge and feed the difference into an op amp. Crank
up the gain on the op amp to whatever you feel comfortable running.

Some simple numbers:

Thermistor changes 3% / C
Single thermistor bridge changes 1.5% / C Output of the circuit will
change the oven by 150C from power off to full on Neglecting the scale
factors for simplicity Put in a gain of 100 on the op amp

So, the bridge moves 1% and the controller goes from full off to full
on.
Crank in more gain "as required". The op amp isn't bothered until you
get into the millions.

With the simplified numbers above, the circuit has a thermal gain of
150. Getting much past 300 with a single oven is unusual.

Bob

> On May 18, 2018, at 2:03 PM, Gilles Clement
<***@club-internet.fr> wrote:
>
> Hi,
> I am trying to improve performance of an OCXO.
> Could you point me at a good design of a high resolution oven
temperature controler please ? Preferably analog.
> Thx much,
> Gilles.

_______________________________________________
time-nuts mailing list -- time-***@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
t***@timeok.it
2018-05-23 08:44:05 UTC
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Raw Message
Hi all,
I found this Crystal Impedande Meter produced by RFL Industries inc, Boonton.
I would like to understand how to use it and I do not have any documentation.
I'm not even able to figure out if it works properly.
I would like to ask you if someone owns the service/operating manual and can share it with me.
Look at the picture thanks
Luciano
Bob kb8tq
2018-05-23 13:43:36 UTC
Permalink
Raw Message
Hi

Gizmo’s like that were very common in the days before network analyzers became
good enough to measure a crystal. They always were a troublesome item to keep
running accurately. Without accuracy, their value was a bit limited. Every place I
know of had a big drawer ( or cabinet ) of “magic crystals”. You plugged them in
and adjusted the instrument until they all read as they should. One could easily
challenge this in terms of accuracy. It did ensure that all the meters in the plant
had some chance of reading the outgoing product the same way.

So - you don’t just need the manual, you also need the batch of calibration crystals
(and their data) that went with it. Then you can duplicate the readings from whatever
factory used it ….

Lots of fun !!!

Bob

> On May 23, 2018, at 4:44 AM, ***@timeok.it wrote:
>
>
> Hi all,
> I found this Crystal Impedande Meter produced by RFL Industries inc, Boonton.
> I would like to understand how to use it and I do not have any documentation.
> I'm not even able to figure out if it works properly.
> I would like to ask you if someone owns the service/operating manual and can share it with me.
> Look at the picture thanks
> Luciano
> <IMG_20180523_102542.jpg>_______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

_______________________________________________
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To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Brooke Clarke
2018-05-23 18:13:00 UTC
Permalink
Raw Message
Hi Luciano:

I have some web pages about crystals and testing them:
http://www.prc68.com/I/CrystalImpedanceMeters.html - Crystal Impedance Meters (Saunders 150)
http://www.prc68.com/I/Xtal.shtml#TE - Crystals in general & Test Equipment (see Trivia below)
http://www.prc68.com/I/Xam.html - Crystal Activity Meters
http://www.prc68.com/I/Xec.shtml - Equivalent Circuit
http://www.prc68.com/I/4395A.shtml#ZT - The Z transform method is also used in commercial crystal test sets like the HP
E4915, E4916, E5100.

Trivia: The HP 4194 may be the only instrument that can really characterize watch crystals ( 32768 Hz) for impedance
which is in the meg Ohms range.  Some of the HP network analyzers can fit swept frequency data into an equivalent
crystal equivalent circuit.

--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html

-------- Original Message --------
> Hi all,
> I found this Crystal Impedande Meter produced by RFL Industries inc, Boonton.
> I would like to understand how to use it and I do not have any documentation.
> I'm not even able to figure out if it works properly.
> I would like to ask you if someone owns the service/operating manual and can share it with me.
> Look at the picture thanks
> Luciano
>
>
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

_______________________________________________
time-nuts mailing list -- time-***@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Bernd Neubig
2018-05-24 05:40:09 UTC
Permalink
Raw Message
Hello,
on the website of my company you can find a list of papers on the subject of crystal measurement techniques.
http://www.axtal.com/English/TechnicalNotes/TechnicalArticlesPublications/LiteratureaboutQuartzCrystals/

The actual standard procedure for crystal measurement is by using modern network analyzers with error correction, as given in the IEC publication 60444-5.
A description of the method and its variants can be found in my 2012 paper listed on the mentioned website.
Enjoy

Bernd DK1AG


-----Ursprüngliche Nachricht-----
Von: time-nuts [mailto:time-nuts-***@febo.com] Im Auftrag von Brooke Clarke
Gesendet: Mittwoch, 23. Mai 2018 20:13
An: ***@timeok.it; Discussion of precise time and frequency measurement <time-***@febo.com>
Betreff: Re: [time-nuts] 5950 Crystal impedance meter manual

Hi Luciano:

I have some web pages about crystals and testing them:
http://www.prc68.com/I/CrystalImpedanceMeters.html - Crystal Impedance Meters (Saunders 150) http://www.prc68.com/I/Xtal.shtml#TE - Crystals in general & Test Equipment (see Trivia below) http://www.prc68.com/I/Xam.html - Crystal Activity Meters http://www.prc68.com/I/Xec.shtml - Equivalent Circuit http://www.prc68.com/I/4395A.shtml#ZT - The Z transform method is also used in commercial crystal test sets like the HP E4915, E4916, E5100.

Trivia: The HP 4194 may be the only instrument that can really characterize watch crystals ( 32768 Hz) for impedance which is in the meg Ohms range. Some of the HP network analyzers can fit swept frequency data into an equivalent crystal equivalent circuit.

--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html

-------- Original Message --------
> Hi all,
> I found this Crystal Impedande Meter produced by RFL Industries inc, Boonton.
> I would like to understand how to use it and I do not have any documentation.
> I'm not even able to figure out if it works properly.
> I would like to ask you if someone owns the service/operating manual and can share it with me.
> Look at the picture thanks
> Luciano
>
>
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

_______________________________________________
time-nuts mailing list -- time-***@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

_______________________________________________
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and follow the instructions there.
Magnus Danielson
2018-05-24 06:07:36 UTC
Permalink
Raw Message
Hi Bernd,

On 05/24/2018 07:40 AM, Bernd Neubig wrote:
> Hello,
> on the website of my company you can find a list of papers on the subject of crystal measurement techniques.
> http://www.axtal.com/English/TechnicalNotes/TechnicalArticlesPublications/LiteratureaboutQuartzCrystals/
>
> The actual standard procedure for crystal measurement is by using modern network analyzers with error correction, as given in the IEC publication 60444-5.
> A description of the method and its variants can be found in my 2012 paper listed on the mentioned website.

I was hoping you would chime in on this thread eventually. Looks very
interesting.

It seems I should do some software processing after sweeping using my
HP4195A. It hss some internal matching, but you have warned that it gets
confused about wide-band or narrow-band properties :)

> Enjoy

Always! :)

Cheers,
Magnus

> Bernd DK1AG
>
>
> -----Ursprüngliche Nachricht-----
> Von: time-nuts [mailto:time-nuts-***@febo.com] Im Auftrag von Brooke Clarke
> Gesendet: Mittwoch, 23. Mai 2018 20:13
> An: ***@timeok.it; Discussion of precise time and frequency measurement <time-***@febo.com>
> Betreff: Re: [time-nuts] 5950 Crystal impedance meter manual
>
> Hi Luciano:
>
> I have some web pages about crystals and testing them:
> http://www.prc68.com/I/CrystalImpedanceMeters.html - Crystal Impedance Meters (Saunders 150) http://www.prc68.com/I/Xtal.shtml#TE - Crystals in general & Test Equipment (see Trivia below) http://www.prc68.com/I/Xam.html - Crystal Activity Meters http://www.prc68.com/I/Xec.shtml - Equivalent Circuit http://www.prc68.com/I/4395A.shtml#ZT - The Z transform method is also used in commercial crystal test sets like the HP E4915, E4916, E5100.
>
> Trivia: The HP 4194 may be the only instrument that can really characterize watch crystals ( 32768 Hz) for impedance which is in the meg Ohms range. Some of the HP network analyzers can fit swept frequency data into an equivalent crystal equivalent circuit.
>
> --
> Have Fun,
>
> Brooke Clarke
> http://www.PRC68.com
> http://www.end2partygovernment.com/2012Issues.html
>
> -------- Original Message --------
>> Hi all,
>> I found this Crystal Impedande Meter produced by RFL Industries inc, Boonton.
>> I would like to understand how to use it and I do not have any documentation.
>> I'm not even able to figure out if it works properly.
>> I would like to ask you if someone owns the service/operating manual and can share it with me.
>> Look at the picture thanks
>> Luciano
>>
>>
>> _______________________________________________
>> time-nuts mailing list -- time-***@febo.com To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
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Gerhard Hoffmann
2018-05-24 08:31:06 UTC
Permalink
Raw Message
The DG8SAQ vector network analyzer has a built-in routine to
characterize crystals.

It may not be "correct" to simply plug them on port 1, but the results
are quite

reasonable. The right thing to sort out a bag of NOS crystals and
finding the good ones

or to get a somewhat realistic simulation model.

regards, Gerhard


Am 24.05.2018 um 08:07 schrieb Magnus Danielson:
> Hi Bernd,
>
> On 05/24/2018 07:40 AM, Bernd Neubig wrote:
>
(good stuff snipped)
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Bob kb8tq
2018-05-24 14:20:51 UTC
Permalink
Raw Message
Hi

Basically when the modern era of network analyzer / standards calibrated devices came along, it was the
end of most of these magic test sets with knobs and dials. The Saunders stuff lived on well into that era,
mainly because it was relatively inexpensive and most of the calibration was simple to do. The conversion
to what we would now call network analyzer techniques was well underway in the 1970’s. It took us quite
a bit of work to get from there to where we are today.

The operating principle of the older magic boxes is fairly simple. Build up an oscillator circuit that can be
switched around to run over a wide range of frequencies and impedances. It generally is a very poor
oscillator, but that’s not the point. Come up with a way to “zero” it to a given impedance and frequency.
Plug in crystals and see how they deviate in impedance and nominal frequency. Shove in a load capacitance
change and note the frequency change. From that data, you can calculate the crystal parameters. To
the degree all the stray this and that is nulled out, your data will be more or less accurate.

Bob

> On May 24, 2018, at 1:40 AM, Bernd Neubig <***@t-online.de> wrote:
>
> Hello,
> on the website of my company you can find a list of papers on the subject of crystal measurement techniques.
> http://www.axtal.com/English/TechnicalNotes/TechnicalArticlesPublications/LiteratureaboutQuartzCrystals/
>
> The actual standard procedure for crystal measurement is by using modern network analyzers with error correction, as given in the IEC publication 60444-5.
> A description of the method and its variants can be found in my 2012 paper listed on the mentioned website.
> Enjoy
>
> Bernd DK1AG
>
>
> -----Ursprüngliche Nachricht-----
> Von: time-nuts [mailto:time-nuts-***@febo.com] Im Auftrag von Brooke Clarke
> Gesendet: Mittwoch, 23. Mai 2018 20:13
> An: ***@timeok.it; Discussion of precise time and frequency measurement <time-***@febo.com>
> Betreff: Re: [time-nuts] 5950 Crystal impedance meter manual
>
> Hi Luciano:
>
> I have some web pages about crystals and testing them:
> http://www.prc68.com/I/CrystalImpedanceMeters.html - Crystal Impedance Meters (Saunders 150) http://www.prc68.com/I/Xtal.shtml#TE - Crystals in general & Test Equipment (see Trivia below) http://www.prc68.com/I/Xam.html - Crystal Activity Meters http://www.prc68.com/I/Xec.shtml - Equivalent Circuit http://www.prc68.com/I/4395A.shtml#ZT - The Z transform method is also used in commercial crystal test sets like the HP E4915, E4916, E5100.
>
> Trivia: The HP 4194 may be the only instrument that can really characterize watch crystals ( 32768 Hz) for impedance which is in the meg Ohms range. Some of the HP network analyzers can fit swept frequency data into an equivalent crystal equivalent circuit.
>
> --
> Have Fun,
>
> Brooke Clarke
> http://www.PRC68.com
> http://www.end2partygovernment.com/2012Issues.html
>
> -------- Original Message --------
>> Hi all,
>> I found this Crystal Impedande Meter produced by RFL Industries inc, Boonton.
>> I would like to understand how to use it and I do not have any documentation.
>> I'm not even able to figure out if it works properly.
>> I would like to ask you if someone owns the service/operating manual and can share it with me.
>> Look at the picture thanks
>> Luciano
>>
>>
>> _______________________________________________
>> time-nuts mailing list -- time-***@febo.com To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

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Tim Shoppa
2018-05-24 17:14:19 UTC
Permalink
Raw Message
I don't know how to use that particular Boonton unit. BUT...

This is a different (more automated) unit which came maybe 10 years later.
The guy does a good job showing how it works and uses it on real crystals:
https://www.youtube.com/watch?v=y-rCgumTn4Q&feature=youtu.be&t=4m37s

Experimental Methods in RF Design shows how to a couple different simple
benchtop jigs to measure crystal motional parameters and compute Q.

Tim N3QE

On Wed, May 23, 2018 at 4:44 AM, ***@timeok.it <***@timeok.it> wrote:

>
> Hi all,
> I found this Crystal Impedande Meter produced by RFL Industries inc,
> Boonton.
> I would like to understand how to use it and I do not have any
> documentation.
> I'm not even able to figure out if it works properly.
> I would like to ask you if someone owns the service/operating manual
> and can share it with me.
> Look at the picture thanks
> Luciano
>
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> and follow the instructions there.
>
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t***@timeok.it
2018-05-25 16:52:47 UTC
Permalink
Raw Message
Hi all,
Thank you all for the precious answers and the links you sent me.
I'm studying them very carefully.
I still continue to look for the manual of the 5950 because I like to keep the manuals of all the measuring instruments I have in my laboratory.
Thanks again
Luciano
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Bernd Neubig
2018-05-25 18:08:04 UTC
Permalink
Raw Message
Hi
Regarding the manuals,
I must look in my paper archive. I remember to have two manuals of two types of those "old test sets". I have even one of the test sets in my "museum".
It will take a while to dig, as I am going to travel for 10 days.

I will come back after that.

Regards
Bernd

-----Ursprüngliche Nachricht-----
Von: time-nuts [mailto:time-nuts-***@febo.com] Im Auftrag von ***@timeok.it
Gesendet: Freitag, 25. Mai 2018 18:53
An: time-***@febo.com
Betreff: [time-nuts] 5950 Crystal impedance meter manual


Hi all,
Thank you all for the precious answers and the links you sent me.
I'm studying them very carefully.
I still continue to look for the manual of the 5950 because I like to keep the manuals of all the measuring instruments I have in my laboratory.
Thanks again
Luciano
_______________________________________________
time-nuts mailing list -- time-***@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

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