Re: [time-nuts] 5950 Crystal impedance meter manual

[Bernd Neubig]

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-boun...@febo.com] Im Auftrag von 
tim...@timeok.it
Gesendet: Freitag, 25. Mai 2018 18:53
An: time-nuts@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
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Re: [time-nuts] 5950 Crystal impedance meter manual

[Bernd Neubig]

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-boun...@febo.com] Im Auftrag von Brooke Clarke
Gesendet: Mittwoch, 23. Mai 2018 20:13
An: tim...@timeok.it; Discussion of precise time and frequency measurement 

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
>
>
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Re: [time-nuts] Suggest time-and-tech related locations in Switzerland

[Bernd Neubig]

Hi Dave,
the center of the Swiss watch & crystal industry is the small town of Grenchen, 
location of many famous watch makers including the SMH group which includes 
Microcrystal, previously also Oscilloquartz, and the following wathc brands:
 Prestige and Luxury:
Breguet (CH)
Blancpain (CH)
Glashütte Original (D)
Jaquet Droz (CH)
Léon Hatot (CH)
Harry Winston (USA)
Omega (CH)
Upper price segment:
Longines (CH)
Rado (CH)
Union Glashütte (D)
Middle price segment:
Tissot (CH)
Calvin Klein (CH)
Balmain (CH)
Certina (CH)
Mido (CH)
Hamilton (CH)
Base segment:
Swatch (CH)
Flik Flak (CH)
Private Label:
Endura (CH)

A few km away is Neuchatel (Neuenburg), a center of time and frequency 
companies.
I am not familiar with museums in that area, but I am sure there are some. I 
think someone else on the list will have more details.
The whole area is the so-called "Swiss Jura". 
The area of time & frequency companies and institutes extends into France up to 
Besancon.
Neuchatel and Besancon are the locations where the EFTF (European Time and 
Frequency Forum) started and is taking place in one of both every two years.

Best regards
Bernd
DK1AG



-Ursprüngliche Nachricht-
Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag von David Witten
Gesendet: Dienstag, 13. März 2018 22:59
An: time-nuts@febo.com
Betreff: [time-nuts] Suggest time-and-tech related locations in Switzerland

My wife and I are traveling to Switzerland for the last week in May.  I have 
never been there before.

I would appreciate suggestions for time / tech sites of interest to visit.

We plan to fly to Zurich, but travel immediately to Geneva and then work our 
way back to Zurich by train, stopping (at least) in Bern.

I would like to see what I can at CERN, I plan to attend the Ham meeting in in 
Friedrichshafen June 1 - 3.

Dave
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Re: [time-nuts] Atomic clocks and Wassenaar agreement

[Bernd Neubig]

Hi Attila,

the paragraph applies also to low phase noise crystal oscillators.
The limiting equation for phase noise stated in that section 3. A. 1. b. 10 
reads as follows:
L(F) > -(126+20log10F-20log10f) for 10 Hz ≤ F ≤ 10 kHz
With f being the carrier frequency in MHz and F the offset in Hz

In the attachment I have added a chart showing the limits for 10 MHz and 100 
MHz.
This equation is rather arbitrary and not conclusive, because it assumes a 
slope of the PN curve close to carrier of -20 dB/decade, while in reality it is 
-30 dB/decade. This means that even if you do not touch the limits very close 
to carrier, the real phase noise may intersect at larger offsets. If you look 
at the numbers, you can easily find that not only a few best in class OCXO will 
touch or crosss the limits, but many normal "industrial state of the art" OCXO 
nowadays will...
I have no idea, where I could place my arguments to advocate a change of this 
unrealistic regulation.

Indeed it may be good that not all customs officers are able (or have the time) 
to solve that equation.

Best regards
Bernd
DK1Ag



-Ursprüngliche Nachricht-
Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag von Attila Kinali
Gesendet: Sonntag, 20. August 2017 12:08
An: Discussion of precise time and frequency measurement 
Betreff: [time-nuts] Atomic clocks and Wassenaar agreement

On Sun, 20 Aug 2017 08:50:59 +
"Poul-Henning Kamp"  wrote:


> >Bob your right its interesting that the sales locations are in China 
> >and India. Perhaps a larger opportunity for a RB reference today.
> 
> Could be because hydrogen masers are dual-use under the Waasenaar Arrangement 
> ?

As far as I can tell, there is no explicit mention of atomic clocks. But the 
list of dual use electronics is long and broad.
E.g. Section 3. A. 1. b. 10. covers basically all low noise frequency sources. 
Including just a simple low-noise XO.

Does anyone have more specific knowledge?

Attila Kinali

--
You know, the very powerful and the very stupid have one thing in common.
They don't alters their views to fit the facts, they alter the facts to fit the 
views, which can be uncomfortable if you happen to be one of the facts that 
needs altering.  -- The Doctor ___
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Re: [time-nuts] Quartz Crystal Motional Movement

[Bernd Neubig]

Bob Camp:
>Every paper I have ever read on the intrinsic Q of quartz makes the claim that 
>Q * F is a constant ( Q goes up as frequency goes down).  Unless blank 
>diameter gets in the way, this has been true for any >crystals I have ever 
>used. Q does change as overtone changes, but that is not related to the Q of 
>the material. A given blank design may (or may not) be limited by the Q of the 
>quartz at any specific >frequency. That is a function of a lot of things. 
>The material’s properties set a maximum Q you can achieve no matter how good 
>your blank design is and how big the blank. Done properly, the best 5 MHz 
>resonator you can do *will* have 2X the Q of >the best 10 MHz resonator. 

Indeed there is an physical limitation for the Q of piezoelectric resonators, 
which is given by phonon interactions etc. For quartz this limit is given 
approximately by Q*f = 15E12. See attached graph (sorry, in German). The real 
crystal Q is determined by a couple of other factors like 
- damping caused by the suspension (which for circular plano-parallel thickness 
shear resonators like AT and SC is the larger, the larger the thickness to 
diameter ratio is. The impact of the suspension can be reduced e.g. by 
contouring the crystal (beveling, plano-convex or bi-convex shape)
- damping by the surrounding gas (dominating in low-frequency tuning-fork type 
crystals, important for low- frequency AT-cut crystals, less important for high 
frequency crystals
- damping effect due to stress and losses between crystal blank and electrodes
- mode of vibration: fundamental is worse than overtones, partly because the 
electrode losses apply only to two outer interfaces of the vibration sublayers
   rule of thumb for ATs with f in Hz: fundamental  mode: Q*f about 1E12, 3rd 
overtone Q*f about 2E12 ... 4E12, 5th and higher overtone 4E12 to 8E12.
   for SC-cut 3rd or 5th overtone with optimized design Q*f can go up to 13E12, 
e.g. Q of a good 10 MHz 3rd is about 1.1 mio to 1.3 mio, a good 100 MHz 5th has 
a q of 120 000 to 135 000
- in tuning fork crystals (which are all evacuated) Q*F is about 0.6E12 to 
1.5E12
Rule of thumb means: these are typical averages , there are exceptions

BTW: This does not apply to the sapphire DIELECTRIC resonators or other kinds 
of resonators like DRO etc.. Those are different animals.

Have fun

Bernd
DK1AG


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Re: [time-nuts] One sure way to kill your FE-5680A or FE-5650A

[Bernd Neubig]

The same problem may appear on some poorly designed crystal oscillators.
Some circuits depend on the spectral component of a fast power-on and will not 
start reliably if the supply voltage is ramped slowly - as can happen if the 
oscillator stage is fed by a voltage regulator with high value capacitor 
blocking at its output.
That is why oscillator testing standards like IEC 60679-1 define the test for 
reliable start-up to consist of a slowly ramping up supply voltage.
Another way to identify potential start-up problems is to cool down the 
unpowered oscillator to the minimum operating temperature (or upper operating 
temperature) and then to apply a slow supply voltage ramp

Bernd
DK1AG
-Ursprüngliche Nachricht-
Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag von jimlux
Gesendet: Mittwoch, 8. Juni 2016 17:21
An: time-nuts@febo.com
Betreff: Re: [time-nuts] One sure way to kill your FE-5680A or FE-5650A

On 6/8/16 6:19 AM, paul swed wrote:
> The units were never intended for a slow ramp I assume it runs into a 
> meta stable condition Neither on or off and then corruption Glad 
> you're can repair them
>
> On Tuesday, June 7, 2016, Bob Camp  wrote:
>
>>

Interesting, we just had a similar issue on a circuit here at work.. 
someone slowly brought the supply voltage up on a bunch of DC/DC converters, 
and some didn't start. This was in initial checkout of a new board.

Switch it on with a bang, and it works just fine.

So for some of these things there's apparently a minimum dv/dt.

I've seen this before with DC/DC converters.. if the voltage drops too low, 
they draw too much current - because they're basically constant power devices- 
and the overcurrent trip shuts them down.  There's a delicate interplay between 
the overcurrent and undervoltage trips,both of which have some sort of time 
constant, and I suspect that for a lot of circuits, the "slow ramp up of input 
voltage" isn't something they are designed for.  Once it's up and running, when 
the supply sags, the UV trip works just fine, tripping before the OC trip goes.


Linear regulators.. they may be not the most efficient thing in the world, but 
they have a lot less "weird" behavior.  (although I've had linear regulators go 
into thermally driven oscillation)




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Re: [time-nuts] How to get unknown frequency quartz crystals oscillating

[Bernd Neubig]

Tim Shoppa wrote:
>The Pierce logic-gate-biased-active oscillator is pretty reliable to start and 
>will oscillate somewhere with most crystals from kHz to MHz.
>As you found out, it will often come up on one of many overtones.
>To reduce chance of coming at an overtone, a series resistor from logic gate 
>output to the crystal is often enough. If not, a RC low-pass will cut down 
>even further (although of course adding phase shift.)

This is certainly the easiest and fastest way for a go/no-go test and to find 
the approximate resonance frequency. 
In the attached circuit diagram make CX1 and CX2 about 10 pF and RGK several 
MegOhms.
The inverter gate should be preferably an unbuffered HCMOS or other fast 
inverter.
For crystals in the MHz range you can replace RV by a short, for kHz crystals 
make it a few kOhms. If testing small watch crystals @ 32768 kHz or around, RV 
should be 100 kOhm at least. RV reduces the crystal drive level (RF current) to 
an acceptable level to avoid overloading or even damaging of the crystal. For 
low frequency crystals the RV-CX2 lowpass also avoids start-up at the overtone.
It is recommended to add a second inverter gate at the output to isolate your 
oscilloscope or counter input from the oscillator stage. Add some >330 ohm in 
series to the output of the 2nd inverter, if you connect a coaxial cable. Then 
terminate the coax at the oscilloscope or frequency counter end with 50 Ohms, 
so the square wave form will be roughly maintained.

In this circuit the crystal will not operate at its series resonance, but at a 
load resonance with load capacitance of something between 8 pF and 10 pF 
(depending on the inverter input and output capacitance plus the stray 
capacitances of your test fixture).
If you want to operate the oscillator at a (low) overtone, such as 3rd (or 
maybe 5th), you must add a series combination of 10 nF plus an inductor in 
parallel to CX2. The 10 nF is to avoid DC short-circuiting of the output. The 
inductor together with CX2 must have a resonance frequency mid between 
fundamental mode and 3rd overtone (not at one of them). So the tuned circuit 
acts like a capacitor at the 3rd OT and is inductive at fundamental mode (thus 
the phase condition for oscillation is not fulfilled at the fundamental mode)
Have fun

Bernd
DK1AG 
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Re: [time-nuts] How can I generate a very clean 1 W signal @ 116 MHz ?

[Bernd Neubig]

Alexander Pummer wrote on  Montag, 30. Mai 2016 16:25

>KVG Neckarbischofshofen used to have a crystal in a glass envelope, which was 
>made just for that purpose it was third overtone crystal ask Bernd if that is 
>still available, of course you would need a low noise power amplifier to get 
>that 1W.
It is true that 20~30 years ago crystals in glass enclosure used to be under 
the top performant precision crystals ...until Coldweld technology was 
"re-discovered" in industry (HP did that before...).
Nowadays glass-sealing technology is no longer available (except by a few new 
manufacturers), as this is a too expensive and delicate process due to the high 
temperature of melting glass comes very close two the quartz crystal.
For a normal transverter type applications there is no need for extra low phase 
noise. As Rick has pointed out, a "regular" 116 MHz AT 5th overtone crystal in 
a resistance-weld HC-49/U (4.9 mm pin spacing) or HC-52/U or UM-1 (3.75 mm pin 
spacing) will do the job perfectly. 
There are a lot of proven circuits out there, most of them work fine with a 
crystal adjusted in series resonance. 
Certainly you can do better with more complex solutions which is like shooting 
canons to sparrows (as we say here in Germany).

BTW: Alternatively you can use a 116 MHz TCXO (as some of our customers are 
doing, getting <-155 dBc/Hz @ 10 kHz with a stability of 0.5 ppm over-10~+60°C) 
- but this is not the place for a commercial, sorry.

Have fun
Bernd
DK1AG

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Re: [time-nuts] Simple solution for disciplining OCXO with 1 PPS

[Bernd Neubig]

Hi fellow time-nuts,
sorry for keeping quiet after having dropped my question. I was busy travelling 
an since yesterday our booth at the IMS2016/MTT keeps me busy too.
I will answer to the various comments as soon as I got some more quiet minutes.
I look forward to see many time-nuts this afternoon at 5:00 pm at the Dynamic 
Engineers booth #714

Bernd

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[time-nuts] Simple solution for disciplining OCXO with 1 PPS

[Bernd Neubig]

Hello Fellow time-nuts,
I am looking for a simple solution to discipline my 10 MHz reference OCXO in my 
private lab with an 1 PPS signal from a separate GPS receiver.
I am curious if there is a solution possible without programming a 
microcontroller, as I am an old-fashioned "analogue" guy ;)
I am well aware, that such a solution would have a lot of disadvantages, as it 
cannot effectively compensate for short-term variations. However I would be 
happy if such a KISS solution could achieve  a stability (STS) of better 1E-10 
over an hour. I know this is a damned long integration time for an analogue 
integrator...
If that sounds too weird, I am open to receive advises for a microcontroller 
based solution.

Thanks a lot for your comments to come.
BTW: you need not to teach me about basics of short-term stability. I just want 
to evaluate the limits of a possible analogue solution. For sure, that's not 
real disciplining, but more like a long-tau integration PLL

Best regards
Bernd DK1AG

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Re: [time-nuts] Get together at IMS?

[Bernd Neubig]

Agreed!
See you on Wed at 5.00pm at Booth 714 (Dynamic Engineers)

-Ursprüngliche Nachricht-
Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag von Mark Kahrs
Gesendet: Sonntag, 22. Mai 2016 16:41
An: Discussion of precise time and frequency measurement <time-nuts@febo.com>
Betreff: Re: [time-nuts] Get together at IMS?

I think this makes it real easy, let's meet at Bernd's booth at 5 p.m. on 
Wednesday.  Bring friends.



On Sat, May 21, 2016 at 3:46 AM, Bernd Neubig <bneu...@t-online.de> wrote:

> I will attend the IMS from Tuesday through Thursday noon time. Most 
> time I will be at booth 714 (Dynamic Engineers).
> Good proposal to meet at the Industry reception on Wednesday. Please 
> come up with a proposal for the meeting point, as the hall is big.
> Best regards
>
> Bernd DK1AG
>
> -Ursprüngliche Nachricht-
> Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag von Mark 
> Kahrs
> Gesendet: Freitag, 20. Mai 2016 15:13
> An: Discussion of precise time and frequency measurement < 
> time-nuts@febo.com>
> Betreff: [time-nuts] Get together at IMS?
>
> Anyone else going to IMS in SFO this coming week?
>
>
> I would propose meeting during the "industry Reception" Wednesday 
> afternoon...
> ___
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Re: [time-nuts] Get together at IMS?

[Bernd Neubig]

I will attend the IMS from Tuesday through Thursday noon time. Most time I will 
be at booth 714 (Dynamic Engineers).
Good proposal to meet at the Industry reception on Wednesday. Please come up 
with a proposal for the meeting point, as the hall is big.
Best regards

Bernd DK1AG

-Ursprüngliche Nachricht-
Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag von Mark Kahrs
Gesendet: Freitag, 20. Mai 2016 15:13
An: Discussion of precise time and frequency measurement 
Betreff: [time-nuts] Get together at IMS?

Anyone else going to IMS in SFO this coming week?


I would propose meeting during the "industry Reception" Wednesday afternoon...
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Re: [time-nuts] 2016 W.G. Cady award

[Bernd Neubig]

Thank you for the congratulations. 
I am very pleased to have received this prestigious award named after Walter G. 
Cady, the guy who has built the first crystal oscillator in 1921.

Bernd Neubig 

-Ursprüngliche Nachricht-
Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag von Dr. Ulrich 
Rohde via time-nuts
Gesendet: Mittwoch, 11. Mai 2016 16:36
An: Discussion of precise time and frequency measurement <time-nuts@febo.com>
Betreff: Re: [time-nuts] 2016 W.G. Cady award

>From me too , Ulrich N 1ul

Sent from my iPhone

> On May 11, 2016, at 8:46 AM, Magnus Danielson <mag...@rubidium.dyndns.org> 
> wrote:
> 
> Goes to Bernd W. Neubig!
> 
> Congratulations Bernd!
> 
> Cheers,
> Magnus
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Re: [time-nuts] IFCS 2016 in New Orleans

[Bernd Neubig]

I will be  I will arrive on Monday late afternoon.
Looking forward to meeting you and other Time Nuts soon

Bernd Neubig - DK1AG
AXTAL GmbH & CO. KG



-Ursprüngliche Nachricht-
Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag von Magnus 
Danielson
Gesendet: Sonntag, 8. Mai 2016 13:42
An: Discussion of precise time and frequency measurement <time-nuts@febo.com>
Cc: mag...@rubidium.se
Betreff: [time-nuts] IFCS 2016 in New Orleans

Fellow time-nuts,

As I will attend the IFCS 2016 in New Orleans there is an opportunity to meet. 
One of the local time-nuts have already reached out and contacted me. Already 
in town.

Cheers,
Magnus
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Re: [time-nuts] Glass Envelope Quartz Crystals

[Bernd Neubig]

Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag von Bob Camp
Gesendet: Mittwoch, 3. Februar 2016 13:12
 >There likely are long stories that explain just why this or that package got 
 >used in this or that application. 

The historical reasons for this type of package is more related to the 
production technology than to a particular application.
In the olde days, before cold-welding technology came up, glass-encapsulation 
was the packaging of choice to achieve high stability crystals. Because of the 
high temperatures associated with the melting during the sealing, all humidity, 
moisture and "dirt" was burned away. In addition the vacuum inside contributes 
for high stability and high Q
The sealing of glass tubes was a well-established technology for vacuum tubes, 
and could be adapted straight-forward by the crystal manufacturers.
Therefore most of these tube-style crystal packages had an "Octal" or "Noval" 
type socket as used for vacuum tubes.

To complete the story:
Later the all-glass enclosures HC-27 and HC-26 came up, which have the same 
outer dimensions and pin spacing as the old HC-6/U and HC-18/U metal 
enclosures. The sealing technology was as follows:
There was a ring of Kovar embedded in the upper side of the header. The 
glass-cover was positioned on top of this Kovar ring.   The output power ( 
around 1 kW) of a RF (e.g. 13.56 MHz) transmitter was inductively coupled 
through a coil which was arranged around the crystal header, so the Kovar ring 
was forming the secondary winding of this RF transformer. Through RF induction 
the Kovar ring was melting and with it the edge of the glass cover and of the 
header. The whole thing happened under a vacuum bell, and the sealing process 
was accompanied by water cooling of the pins and parts of the header to avoid 
overheating of the crystal during the melting process (its temperature must be 
maintained well below the Curie temperature (573°C). The degree of overheating 
could be seen afterwards by you measuring the resonance spectrum:
At about 1.5 times the nominal frequency you could see resonances from the 
BT-cut mode, caused by partial twinning of the crystal structure ...

With this I will close the crystal history book for today.

Best regards

Bernd
DK1AG

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Re: [time-nuts] Looking for paper "Theory and Properties of Piezoelectric Resonators and Waves"

[Bernd Neubig]

Hello Attila,

I do have the book. Sorry, but I have no time to scan the pages.
Please call me in the QRL

Viele Grüße

Bernd  DK1AG

AXTAL GmbH & Co. KG


-Ursprüngliche Nachricht-
Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag von Attila Kinali
Gesendet: Dienstag, 2. Februar 2016 14:33
An: Discussion of precise time and frequency measurement 
Betreff: [time-nuts] Looking for paper "Theory and Properties of Piezoelectric 
Resonators and Waves"

Moin,

I'm looking for a paper, but cannot find it in a local library or digital form. 
Before I start ordering old conference proceedings, I wanted to ask whether 
anyone here has the paper and would be so kind to send me a (digital) copy.

The paper I am looking for is:

T. R. Meeker, "Theory and Properties of Piezoelectric Resonators and Waves"
by E. A. Gerber and A. Ballato, in Precision Frequency Control, Vol. 1, pp. 
48-118, Academic Press, 1985.


Thanks in advance

Attila Kinali
-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] 8th Symposium on Frequency Standards and Metrology

[Bernd Neubig]

Hi Magnus,

I had planned to attend and had even submitted a poster, which was accepted. 
However due to time constraints I had to cancel my trip.
Have a nice stay.

Best regards

Bernd DK1AG
AXTAL GmbH & Co. KG

BTW: If you have spare time and we can find a time slot from our side, you 
would be welcome to visit AXTAL lab during your journey. We are located in 
Mosbach, 70 km north of Stuttgart, 130 km south of Frankfurt

-Ursprüngliche Nachricht-
Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag von Magnus 
Danielson
Gesendet: Freitag, 9. Oktober 2015 20:55
An: Discussion of precise time and frequency measurement 
Cc: mag...@rubidium.se
Betreff: [time-nuts] 8th Symposium on Frequency Standards and Metrology

Fellow time-nuts,

Next week is filled with interesting stuff as we gather in Potsdam for this:

https://www.ptb.de/8fsm2015/about-the-symposium/

I and Attila will be there, so who will join us?

PS. For the moment I actually don't know how many Cs-clocks I have... 
it's complicated.

Cheers,
Magnus
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Re: [time-nuts] Vintage Crystal Oven

[Bernd Neubig]

I have a few similar thermostats, which were sold in the 70ies by KVG Germany 
under their P/N XT-1. The manufacturer was Northern Engineering.
The oven comprises an Octal type tube socket, in the interior there are two 
sockets for two HC-6/U style crystals. The temperature control is by a 
bi-metal switch in series with the heater coil, which is a resistor wire wound 
around the cylindrical body. I had measured the temperature stability those 
days, the test report is still in the box ;) The thermal hysteresis of the 
bi-metal switch causes a periodic temperature change within 0.3 K, which is not 
too bad.

Best regards

Bernd  DK1AG
www.axtal.com

-Ursprüngliche Nachricht-
Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag von Dave M
Gesendet: Samstag, 11. April 2015 00:48
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] Vintage Crystal Oven

Thanks George,
I used to work in a Motorola 2-way shop.  The only heated ovens that Motorola 
used were the 6.3V thermostatically controlled ovens.  Those were used in the 
old tube-style units.  When they went solid-state, they used TXCOs in both base 
and mobile units.
However, I'll check them out.  Never know, there might be something useful 
there.

Cheers,
Dave M


George Dubovsky wrote:
 I'm not sure I remember the exact one you are describing, but in the 
 last month or so, there was a fellow selling crystal ovens on QTH.com. 
 I think they were from land-mobile service, like Motorola base 
 stations or some such. That's another place to search.

 73,

 geo - n4ua

 On Fri, Apr 10, 2015 at 12:37 PM, Dave M dgmin...@mediacombb.net
 wrote:

 Years ago, (70s maybe) I came across an empty crystal oven. I know I 
 have it in one of the storage containers of old stuff in my garage, 
 but I can't find it.  It was a proportional oven, but was otherwise 
 an empty shell, so you could put your own circuitry inside 
 (oscillator, voltage reference, etc.). Several small wires came out 
 of it for power, temperature adjustment, e.g. Physical size was in 
 the neighborhood of 1.5x1.5x3 inches.
 As I remember, it was manufactured by one of the major crystal 
 manufacturers of the day (e.g., Knight, Bliley, etc.)

 Does anyone remember these ovens?  I'd surely like to get my hands on 
 a couple or three to play with.  I search the net  Ebay occasionally 
 for them, but so far, no hits.

 Dave M


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Re: [time-nuts] OCXO Voltage Input? (Bob Camp)

[Bernd Neubig]

Hi Bob,

your example is correct. However I was not talking about OCXO specifically, but 
about crystal oscillators in general. And the effect I have mentioned is not 
limited to wide-pull VCXO, but may occur at normal VCXO also. I named the 
modulation audio for sake of simplicity of expression - it was certainly not 
accurate enough. If you are modulating data (FSK) then such interferences have 
a risk to occur even at moderate data rates.
I do not talk about theorectical can be's but about practical experience.

Best regards

Bernd
 

-Ursprüngliche Nachricht-
Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag von Bob Camp
Gesendet: Donnerstag, 11. September 2014 00:18
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] OCXO Voltage Input? (Bob Camp)

Hi

If you are modulating a normal OCXO EFC with audio, and the output frequency is 
not being multiplied up, the modulation index will be very low. Low modulation 
index means that the higher order FM sidebands will be quite far down. 

If you take “audio” to be  10 KHz, and a VHF OCXO to be 100 MHz: With a 10 ppm 
EFC range, you get 1.0 KHz of deviation. The modulation index is  1 a decade 
below your upper modulation frequency. That’s already a pretty wide swing OCXO 
and a fairly high modulation frequency for an EFC line. 

If you have a spur that is in the 50 to 150 KHz range, you are talking about 
the 5th to 15th sideband off of 10 KHz or the 50th to 150th sideband off of 1 
KHz. At 50 sidebands out and an index of 1, you are in the “forget about it” 
region. Even at 10 KHz, the sideband is not likely to create much of an issue. 
The distortion from the non-linear EFC slope will be more of a problem in a 
practical sense. 

——

Since the modulation is single sideband, yes it converts PM - AM. It also 
will be impacted by any limiters in the system and will not multiply the same 
way as a pure PM modulation. The phase of the sideband will change as you go 
through the resonance, further messing up the multiplication / limiter math. 

Bob

On Sep 10, 2014, at 12:50 PM, Magnus Danielson mag...@rubidium.dyndns.org 
wrote:

 Bernd,
 
 Brilliant point. Easy to miss if one has a to simple model of the oscillator 
 at hand.
 
 Since it is a single-side-band mode, it will show up both as AM and PM with 
 the same amplitude.
 
 Cheers,
 Magnus
 
 On 09/10/2014 03:27 PM, Bernd Neubig wrote:
 Hi Bob,
 
 your description oft he spurious coming from higher overtone of 
 low-frequency modes is correct. I want to add, that all thickness-shear mode 
 crystals (such as AT, BT and SC-cut) have so-called an-harmonic spurious 
 modes, which is a whole ensemble of spurs located  slightly above above the 
 main mode (fundamental or overtone mode). slightly means starting at about 
 50 kHz to 200 kHz above for fundamental mode and about 30 ... 50 kHz above 
 for overtone modes. These an-harmonic modes are relaled to the length and 
 width of the active area (electrode).
 These spurious modes do not come only into play for wide-pull VCXO, but also 
 in the case that the EFC input is used for modulation with signals in the 
 audio frequency range.
 Remember that a frequency modulated signal has side-lines which are N* the 
 audio frequency apart from the carrier. The amplitude of these side lines 
 follows the so-called Bessel functions and varies with the modulation index.
 If it happens that such a Bessel-line for a particular modulation 
 frequency coincides with such a spur, it comes to an interference, This 
 means the modulation frequency response becomes a discontinuity (dip) at a 
 sharp frequency. Such band breaks do even occur if the spurious is so weak 
 that it can barely be seen on a network analyzer.
 
 Regards
 
 Bernd   DK1AG
 AXTAL GmbH  Co. KG
 www.axtal.com
 
 -Ursprüngliche Nachricht-
 Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag von Bob 
 Camp
 Gesendet: Sonntag, 7. September 2014 04:21
 An: Discussion of precise time and frequency measurement
 Betreff: Re: [time-nuts] OCXO Voltage Input? (Bob Camp)
 
 Hi
 
 Simple answer = crystals are never perfect.
 
 Longer winded, but very incomplete answer =
 
 A spurious response in a crystal normally refers to a mode that is not one 
 of the “identified” modes of the crystal. An AT has a set of identified 
 modes, an SC has a more complex set of modes. In the case of the AT it would 
 be the fundamental and the odd overtones. In the case of the SC you have the 
 A, B, C modes and their odd overtones. None of those are considered spurious.
 
 A spur can come from a lot of different places.  One common one is higher 
 order vibrations in a longer dimension face of the resonator. The 183rd 
 overtone of the width of the blank is still a legitimate resonant mode. 
 Another source are modes other than shear (like flex). Deriving a full 
 catalog of all the modes of an arbitrary blank design is a major project. 
 There are only a handful

Re: [time-nuts] OCXO Voltage Input? (Bob Camp)

[Bernd Neubig]

Hi Bob,

your description oft he spurious coming from higher overtone of low-frequency 
modes is correct. I want to add, that all thickness-shear mode crystals (such 
as AT, BT and SC-cut) have so-called an-harmonic spurious modes, which is a 
whole ensemble of spurs located  slightly above above the main mode 
(fundamental or overtone mode). slightly means starting at about 50 kHz to 200 
kHz above for fundamental mode and about 30 ... 50 kHz above for overtone 
modes. These an-harmonic modes are relaled to the length and width of the 
active area (electrode).
These spurious modes do not come only into play for wide-pull VCXO, but also in 
the case that the EFC input is used for modulation with signals in the audio 
frequency range.
Remember that a frequency modulated signal has side-lines which are N* the 
audio frequency apart from the carrier. The amplitude of these side lines 
follows the so-called Bessel functions and varies with the modulation index.
If it happens that such a Bessel-line for a particular modulation frequency 
coincides with such a spur, it comes to an interference, This means the 
modulation frequency response becomes a discontinuity (dip) at a sharp 
frequency. Such band breaks do even occur if the spurious is so weak that it 
can barely be seen on a network analyzer.

Regards

Bernd   DK1AG
AXTAL GmbH  Co. KG
www.axtal.com

-Ursprüngliche Nachricht-
Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag von Bob Camp
Gesendet: Sonntag, 7. September 2014 04:21
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] OCXO Voltage Input? (Bob Camp)

Hi

Simple answer = crystals are never perfect.

Longer winded, but very incomplete answer =

A spurious response in a crystal normally refers to a mode that is not one of 
the “identified” modes of the crystal. An AT has a set of identified modes, an 
SC has a more complex set of modes. In the case of the AT it would be the 
fundamental and the odd overtones. In the case of the SC you have the A, B, C 
modes and their odd overtones. None of those are considered spurious. 

A spur can come from a lot of different places.  One common one is higher order 
vibrations in a longer dimension face of the resonator. The 183rd overtone of 
the width of the blank is still a legitimate resonant mode. Another source are 
modes other than shear (like flex). Deriving a full catalog of all the modes of 
an arbitrary blank design is a major project. There are only a handful of 
people out there who are into that sort of thing (as opposed to simply cranking 
through some formulas).  

Practical answer = Don’t worry about it. Unless you are building a wide pull 
VCXO or a wide deviation VCXO (often the same thing) you will never notice 
them. 

Bob

On Sep 6, 2014, at 9:13 PM, Hal Murray hmur...@megapathdsl.net wrote:

 
 kb...@n1k.org said:
 The biggest problem comes from crystal spurs rather than crystal Q. 
 
 What's the mechanism for making spurs with a crystal?
 
 --
 These are my opinions.  I hate spam.
 
 
 
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Re: [time-nuts] temperature sensor

[Bernd Neubig]

Hi Attila, 
sorry, I was out for a week, so I can respond only now.
Unfortunately I have no data about the thermal resistance crystal to case. It's 
on my agenda since quite a while to measure the time constant.
Tuning fork crystals are in general in an evacuated package, because any 
atmosphere would damp the vibration dramatically, and would increase the 
resonance resistance (which already is in the range of 50k to 100k over 
temperature) severely.
Therefore the thermal connection is mainly through the wires directly to the 
crystal element.  There is some contribution of thermal radiation from the 
cylindrical cover to the crystal, but the main mechanism is thermal conduction 
through the wires.
But as the mass of the tuning fork is so small, it's thermal capacity is small 
and thus it will react pretty quickly.
I really need to put this test on my agenda.

Best regards

Bernd DK1AG

-Ursprüngliche Nachricht-
Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag 
von Attila Kinali
Gesendet: Samstag, 19. Juli 2014 13:46
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] temperature sensor

On Wed, 25 Jun 2014 14:21:49 +0200
Bernd Neubig bneu...@t-online.de wrote:

 the time-nut approach for temperature measurement would be to use  a 
temperature sensor crystal - like the good old Hewlett-Packard guys did 
many years ago. If you do not look for ultra-linearity of the frequency  
vs. temp response, there are several possible types of crystal cuts  
possible. The simplest one is the Y-cut or the slightly rotated Y+5° 
cut,  which has a slope of about 90 to 95 ppm/K @ room temperature.
 Smaller sensor crystals are tuning-fork type crystals, which  come in 
the same small cylindrical package as normal watch crystals.
 For further reading I have attached an application note for such a  
crystal from AXTAL.

Do you have any data on the temperature resistance from case to crystal?
The PT100 and NTC sensors have the nice property of having a very good thermal 
coupling between the sensor element and the case. But i suspect that 
temperature sensor crystals have a very small area that couples the crystal to 
the case (in order to get a high enough Q for the oscillator to work), which in 
turn limits the speed at which the sensor reacts to temperature changes.

Attila Kinali

--
I pity people who can't find laughter or at least some bit of amusement in the 
little doings of the day. I believe I could find something ridiculous even in 
the saddest moment, if necessary. It has nothing to do with being superficial. 
It's a matter of joy in life.
-- Sophie Scholl
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Re: [time-nuts] temperature sensor

[Bernd Neubig]

Hi Bob,

see my answer to Attila, which I have sent a minute ago.

Bernd  DK1AG

-Ursprüngliche Nachricht-
Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im
Auftrag von Bob Camp
Gesendet: Samstag, 19. Juli 2014 15:00
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] temperature sensor

Hi

A “temperature sensor crystal” is very much the same thing as a normal
crystal (except for angle of cut). The mounting is pretty much the same as
the crystals you have seen before. The only thing you do to improve the
thermal coupling is to do a backfill with something like helium. Backfill
levels are low and they vary depending on the application and the cut of
crystal. The thermal resistance isn’t great, but it’s good enough. You only
have micro watts going into the resonator. Increasing the backfill would
increase the damping and thus the resistance. That would increase the power
dissipated in the resonator. This would defeat any gain you got from the
increased backfill. 

For direct contact sensing, you use SAW devices rather than BAW’s. If you do
things “right” you can put the SAW directly in contact with the “stuff” you
are sensing. The thermal resistance in that case is essentially zero. 

Bob

On Jul 19, 2014, at 7:45 AM, Attila Kinali att...@kinali.ch wrote:

 On Wed, 25 Jun 2014 14:21:49 +0200
 Bernd Neubig bneu...@t-online.de wrote:
 
 the time-nut approach for temperature measurement would be to use a 
 temperature sensor crystal - like the good old Hewlett-Packard guys 
 did many years ago. If you do not look for ultra-linearity of the 
 frequency vs. temp response, there are several possible types of 
 crystal cuts possible. The simplest one is the Y-cut or the slightly 
 rotated Y+5° cut, which has a slope of about 90 to 95 ppm/K @ room
temperature.
 Smaller sensor crystals are tuning-fork type crystals, which come in 
 the same small cylindrical package as normal watch crystals.
 For further reading I have attached an application note for such a 
 crystal from AXTAL.
 
 Do you have any data on the temperature resistance from case to crystal?
 The PT100 and NTC sensors have the nice property of having a very good 
 thermal coupling between the sensor element and the case. But i 
 suspect that temperature sensor crystals have a very small area that 
 couples the crystal to the case (in order to get a high enough Q for 
 the oscillator to work), which in turn limits the speed at which the 
 sensor reacts to temperature changes.
 
   Attila Kinali
 
 --
 I pity people who can't find laughter or at least some bit of 
 amusement in the little doings of the day. I believe I could find 
 something ridiculous even in the saddest moment, if necessary. It has 
 nothing to do with being superficial. It's a matter of joy in life.
   -- Sophie Scholl
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Re: [time-nuts] temperature sensor

[Bernd Neubig]

Hi,

regarding the commercial availability of temperature sensor crystals, I
already had pointed to the tuning fork type RKTV206, which is on the AXTAL
website together with an application note.
Other temperature sensing crystals are using thickness shear mode, and are
basically rotated Y- cuts
The most prominent cut is the Y-cut or the same with a few degrees (about 5)
rotation from Y-axis. This cut exhibits a tempco of about -90 ppm/K, but is
not very linear. There are a few on the market in HC-52/U size.
The most temperature-linear cut was the LC-cut invented by olde
Hewlett-Packard, which had a complete temperature test system offered around
this sensor crystal. It is an doubly-rotated cut with some -40 ppm/K
sensitivity. Sorry I am in a hurry, so I have not the time to dig the
literature for you at the moment.

Regards

Bernd  DK1AG


-Ursprüngliche Nachricht-
Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im
Auftrag von Attila Kinali
Gesendet: Sonntag, 20. Juli 2014 18:11
An: Tom Van Baak; Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] temperature sensor

Moin,

On Sun, 20 Jul 2014 07:55:23 -0700
Tom Van Baak t...@leapsecond.com wrote:

 Thanks for this level of detail. Fascinating. Is the fundamental 
 physics behind the quartz angle-of-cut well understood, or does this 
 fall into advanced alchemy and industrial magic?

From what i gathered from my excursion into solid state phyiscs, the
properties of crystals can be calculated easily. If i'm not mistaken the
SC cut was calculated before it was experimentally proven (sorry, cannot
find the reference for that).

There are also several software packages to simulate quartz crystals.
(e.g. CS-01 from maxis-01)


 I understand about the time constant now. Yes, on the order of a few 
 seconds makes sense. Would it be possible to have other mounting 
 techniques that improve environmental contact with the crystal?

The problem here is, that any closer contact will lead to damping of the
crystal. Probably the best solution is, as Bob Camp said, to use SAW instead
of BAW.

 Do you know of any commercial quartz crystals (say, in the $1 to $10 
 range) that have been optimized for large tempco at room temperature? 
 Or optimized for linearity over a large range (e.g., -40 to +40 C)?

As Bernd Neubig mentioned, Axtal has some:
http://www.axtal.com/English/Products/PiezoSensors/TemperatureSensors/

As none of the usual distributors carries them, i have no idea what the
price is. Maybe Bernd can answer that question.

I'm pretty sure other quartz manufacturers have some as well.

 I was able to test
 one once, a 5x7mm XO, but I don't know any more about it other than it 
 came from Switzerland.

Hmm... The only quartz manufacturer in Switzerland that is still producing
anything, is AFAIK Microcrystal. I'm not aware of any other (after
Oscilloquartz got bought and their quartz business integrated into
Microcrystal).

Unless you got it over Quarz AG (www.quarz.ch) which is merly a distributor.
(Yes, they sell beauty products too... )

BTW: for some reason, i did not get the two mails from Andras Pummer which
you quoted at the end of your mail. They don't seem to be in the archives
either.

Attila Kinali


--
I pity people who can't find laughter or at least some bit of amusement in
the little doings of the day. I believe I could find something ridiculous
even in the saddest moment, if necessary. It has nothing to do with being
superficial. It's a matter of joy in life.
-- Sophie Scholl
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Re: [time-nuts] temperature sensor

[Bernd Neubig]

Hi,

the time-nut approach for temperature measurement would be to use a temperature 
sensor crystal - like the good old Hewlett-Packard guys did many years ago.
If you do not look for ultra-linearity of the frequency vs. temp response, 
there are several possible types of crystal cuts possible. The simplest one is 
the Y-cut or the slightly rotated Y+5° cut, which has a slope of about 90 to 95 
ppm/K @ room temperature.
Smaller sensor crystals are tuning-fork type crystals, which come in the same 
small cylindrical package as normal watch crystals.
For further reading an application note for such a crystal from AXTAL can be 
found here:
http://www.axtal.iwebfree.de/cms/iwebs/download.aspx?id=87592

Vy 73
Bernd  DK1AG


-Ursprüngliche Nachricht-
Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag 
von Didier Juges
Gesendet: Mittwoch, 25. Juni 2014 02:12
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] temperature sensor

After having tried just about every solution under the sun, my opinion is that 
within the ambient temperature range (up to at least 100°C) and homebrew 
budgets, nothing beats an NTC thermistor. 

They are inexpensive, have a large output and interface most easily with a 
microcontroller's ADC in ratiometric mode requiring a single precision 
resistor. Even cheap ones have a 1% tolerance which is more precision than you 
will ever need.

My favorite is a 10k at 25°C with a B factor of 3380 at 25/85 that costs $1.25 
at Digikey. The math to derive the temperature from the ADC reading is simple 
(you do need the log function) and a mundane 12 bit ADC gives you temperature 
with a fraction of a degree resolution and much better than a degree absolute 
precision if you actually needed it. With a 2.5V reference (like those in my 
favorite Silabs uC), self heating is negligible, even in open air (a fraction 
of a degree).

This is implemented in my Thunderbolt Monitor kit software to measure ambient 
temperature.

If you need better resolution than what you can get by directly measuring the 
voltage at the junction of the resistor and thermistor (due to limited 
resolution of the ADC), add one op-amp and three resistors, or use the PGA if 
your microcontroller has one.

Didier KO4BB


On June 24, 2014 6:43:07 PM CDT, Chris Albertson albertson.ch...@gmail.com 
wrote:
On Tue, Jun 24, 2014 at 3:24 PM, Mark Sims hol...@hotmail.com wrote:

 ...
 However it is disappointing that no one has stepped up to tackle the 
 temperature problem.


I can post what I have.  It's a uP based PWM fan controller.  It is a 
stand alone device that does not know anything about the FE5680 but it 
would be easy to add into any GPSDO using the GPSDO's existing uP 
provided there were enough extra analog pins available.  It uses the 
Arduino software environment but I built it using a bare 8-pin DIP.
The problem with it is I do not have a good temperature sensor, The 
ones I tried are noisy.
SO
I'm looking forward to your sensor info.

My first controller used a comparator chip.  Then I figured the uP was 
the same cost and same 8-pin package but could do things like PID, data 
logging, led status blinking and whatever.  This is a start on the 
code that works just like the comparator and uses a pot for the user to 
adjust a set point.

If you see a way to make this better post the changes.
Some things I will do are (1) use better sensor, (2) use PID library,
(3)
measure ambient air temp.
FanController.ino
https://dl.dropboxusercontent.com/u/28915695/FanController.ino

BTW is there any design info on the FE5680 controller.  Schematics of 
source code?



--

Chris Albertson
Redondo Beach, California
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--
Sent from my Motorola Droid Razr HD 4G LTE wireless tracker while I do other 
things.
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Re: [time-nuts] Morion MV89 and LTC6957

[Bernd Neubig]

Hi Attila,

 Unfortunately, since they redesigned their webpages, i cannot find the
OCXOs listed anywhere anymore (only the 8607 shows up).
Oscilloquartz has discontinued their OCXO line. The only exception is the
BVA OCXO.

Best regards

Bernd DK1AG
www.axtal.com

-Ursprüngliche Nachricht-
Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im
Auftrag von Attila Kinali
Gesendet: Samstag, 9. November 2013 09:04
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] Morion MV89 and LTC6957

On Fri, 8 Nov 2013 16:55:29 +0100
HagaaarTheHorrible hagaaar587pl...@googlemail.com wrote:

 Doesn't sound too good I'm afraid... in addition to the shipping issues, I
wonder if it was the right decision to use this OCXO...
 Are there any low phase noise OCXO available (preferably from stock) 
 from more conventional sellers? (i.e. distributors/online shops 
 based in US or EU)

The Oscilloquartz 8663 has been superseeded by a newer version.
Unfortunately, since they redesigned their webpages, i cannot find the OCXOs
listed anywhere anymore (only the 8607 shows up).

But you can contact them directly. The Oscilloquartz sales departement is
very helpfull, even towards hobbists.

Attila Kinali

--
1.) Write everything down.
2.) Reduce to the essential.
3.) Stop and question.
-- The Habits of Highly Boring People, Chris Sauve
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Re: [time-nuts] Interesting looking crystal on ebay

[Bernd Neubig]

It may be interesting to know, that the odd number of the pin spacing of the
HC-6/U (12.35 mm) comes from the octal tube socket.
With that pin spacing you can put two HC-6u/U crytals in one socket.
The same is hor HC-18/U. It' pin spacing (4.88 mm), which fits into a noval
tube socket accordingly.

Regards

Bernd Neubig 
DK1AG  
www.axtal.com

-Ursprüngliche Nachricht-
Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im
Auftrag von Max Robinson
Gesendet: Freitag, 8. März 2013 04:19
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] Interesting looking crystal on ebay

I have in my collection of objects, my wife calls it junk, a 100 kHz crystal
in a package that looks like an octal base tube.  It was cast off from
somewhere and is in an oven but I can't find a circuit that will make it
oscillate at 100 kHz.  That is probably the reason it was cast off.  An HP
wave analyzer, model number forgotten, used several similar appearing
crystals in the narrow band filter of the 100 kHz IF.  Also the HP 3570A
network analyzer uses three of them  the 100 kHz IF in each channel.  It
wouldn't surprise me to learn that the same engineer designed the IF strip
for both instruments.

Regards.

Max.  K 4 O DS.

Email: m...@maxsmusicplace.com

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Re: [time-nuts] What cut do I have?

[Bernd Neubig]

Hi,
IT and FC cut crystals are not very often used in OCXO. But if, then the
lower turn point is used (below the inflection temperature), which means
that the cold oven starts at a lower frequency, which increases with warm-up
- same direction as for SC-cut crystals.

Regards

Bernd
DK1AG

-Ursprüngliche Nachricht-
Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im
Auftrag von Bob Camp
Gesendet: Montag, 28. Januar 2013 03:39
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] What cut do I have?

Hi

It could also be an AT, IT or FC cut. A lot depends on just how hot the oven
is running. Best bet is indeed AT.

Bob

On Jan 27, 2013, at 7:40 PM, Magnus Danielson mag...@rubidium.dyndns.org
wrote:

 On 01/28/2013 01:01 AM, Ed Breya wrote:
 If you meant to say the frequency starts out too high when the oven 
 is cold, then I think it's AT cut.
 
 OK. I looked at the previous posts and it was not very clear from them,
and I was too lazy/busy to heat up an idel AT OCXO. I just felt the +41.4
ppm deviation was a little low for an AT cut.
 
 Meanwhile, out of 22 LPROs tested, only 3 has BITE error, so 19 locks up.
Out of 4 cesiums tested, 3 locks up and one fails. Trimming needed on all.
 
 Cheers,
 Magnus
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Re: [time-nuts] What cut do I have?

[Bernd Neubig]

Hi Bob,

you are right. Sorry for my mistake.
FC (and some) IT cut crystals are used in OCXO, because the curvature around
the upper turn point is flatter than for an AT- cut with the same
turn-over temperature. 
IT-cut crystals are sometimes used, when the oven temperature must be in the
range 95 to 100°C, because the operating temp of the OCXO must cover the
whole industrial temperature range up to 85°C.
The yield is higher than using SC-cut crystals for such applications.

Bernd

-Ursprüngliche Nachricht-
Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im
Auftrag von Bob Camp
Gesendet: Montag, 28. Januar 2013 18:40
An: 'Discussion of precise time and frequency measurement'
Betreff: Re: [time-nuts] What cut do I have?

Hi

The only time I've seen them used in OCXO's both the FC and IT were run on
the upper turn (just like an AT). Thus the frequency goes down as it warms
up.

Bob




-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Bernd Neubig
Sent: Monday, January 28, 2013 11:48 AM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] What cut do I have?

Hi,
IT and FC cut crystals are not very often used in OCXO. But if, then the
lower turn point is used (below the inflection temperature), which means
that the cold oven starts at a lower frequency, which increases with warm-up
- same direction as for SC-cut crystals.

Regards

Bernd
DK1AG

-Ursprüngliche Nachricht-
Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im
Auftrag von Bob Camp
Gesendet: Montag, 28. Januar 2013 03:39
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] What cut do I have?

Hi

It could also be an AT, IT or FC cut. A lot depends on just how hot the oven
is running. Best bet is indeed AT.

Bob

On Jan 27, 2013, at 7:40 PM, Magnus Danielson mag...@rubidium.dyndns.org
wrote:

 On 01/28/2013 01:01 AM, Ed Breya wrote:
 If you meant to say the frequency starts out too high when the oven 
 is cold, then I think it's AT cut.
 
 OK. I looked at the previous posts and it was not very clear from 
 them,
and I was too lazy/busy to heat up an idel AT OCXO. I just felt the +41.4
ppm deviation was a little low for an AT cut.
 
 Meanwhile, out of 22 LPROs tested, only 3 has BITE error, so 19 locks up.
Out of 4 cesiums tested, 3 locks up and one fails. Trimming needed on all.
 
 Cheers,
 Magnus
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Re: [time-nuts] 12.8 MHz OCXO

[Bernd Neubig]

Hi Joe,

I can offer you from our stock at AXTAL the following excellent:
- OCXO 12.8 MHz in 20x20 mm package HCMOS, 5 V, stability +-10  ppb, as our
AXIOM30-50-10, but with reference voltage output of 4 V (instead of 3 V).
Frequency can be tuned by using the VREF.
See www.axtal.com for details
Special ham price EUR 98.00 (or equivalent in US-$ plus freight. Payment by
Paypal.
I am not sure, if the freight cost may kill the opportunity for you.

Bernd
DK1AG

-Ursprüngliche Nachricht-
Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im
Auftrag von Joseph Gray
Gesendet: Samstag, 24. November 2012 09:26
An: Discussion of precise time and frequency measurement
Betreff: [time-nuts] 12.8 MHz OCXO

Can anyone recommend an inexpensive 12.8 MHz OCXO that outputs a sine wave?
I've looked online, but the only ones I find costs hundreds of dollars.
Anything 0.25 ppm or better is fine. A Vcc of 5-13.8 VDC preferred.

Joe Gray
W5JG

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Re: [time-nuts] HP/Agilet counter 53131A (not 53151A) trigger problems

[Bernd Neubig]

Hi Azelio,

Sorry, the counters are 53131A, not 53151A. The A and B inputs are specified
from DC to 225 MHz with a sensitivity of y20 mV (rms) up to 100 MHz, 30 mV
(rms) 100 ~ 200 MHz, and 50 mV (rms) 200 ~ 225 MHz. 
The problem can be at either input alone. The problem is only in the range
between 100 MHz and 200 MHz, observed in automatic trigger mode. In manual
trigger mode the counter does not trigger at all in that freq range.

I cannot tell you an aging model for a particular OCXO, and I doubt if
anyone can ;) Aging predictions can only be made on individual OCXO, unit by
unit, and the prediction is only valid over a rather limited time. Therefore
you must continuously monitor and update your prediction.

Best regards

Bernd
DK1AG 

-Ursprüngliche Nachricht-
Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im
Auftrag von Azelio Boriani
Gesendet: Freitag, 24. August 2012 17:28
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] HP/Agilet counter 53151A trigger problems

From the datasheet:
A input 10Hz..125MHz min level 25mVrms (-19dBm) B input min 50MHz, -20dBm
the problem is on A input only? Maybe 150MHz for the A input, being beyond
the official specifications, requires more signal on one counter than the
other. In the past they all were fine?
I have read your paper on the correlation between the real and predicted
aging of crystal oscillators. I'm trying to find a suitable model for the
Morion MV201 OCXO or the Oscilloquartz 8663 to implement a Kalman filter.

On Fri, Aug 24, 2012 at 3:34 PM, Bernd Neubig bneu...@t-online.de wrote:

 Hi all,

 I have several HP/Agilent frequency counters 53151A (and 53152A) in my
lab.
 Several of them meanwhile show trigger problems.

 I have tested the A and B channel between 5 MHz and 200 MHZ at three 
 input levels of -10 dBm, 0 dBm and +10 dBm.

 Those with trigger problems show erroneous numbers at -10 dBm input 
 level rather selectively, i.e. mostly at 100 MHz, some also at 150 
 MHz, while the are o.k.

 Has anyone on this list experienced similar defects and can give a 
 recommendation how to fix/repair them?



 Best regards



 Bernd

 DK1AG

 www.axtal.com

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[time-nuts] HP/Agilet counter 53151A trigger problems

[Bernd Neubig]

Hi all,

I have several HP/Agilent frequency counters 53151A (and 53152A) in my lab.
Several of them meanwhile show trigger problems.

I have tested the A and B channel between 5 MHz and 200 MHZ at three input
levels of -10 dBm, 0 dBm and +10 dBm.

Those with trigger problems show erroneous numbers at -10 dBm input level
rather selectively, i.e. mostly at 100 MHz, some also at 150 MHz, while the
are o.k.

Has anyone on this list experienced similar defects and can give a
recommendation how to fix/repair them?

 

Best regards

 

Bernd

DK1AG

www.axtal.com

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Re: [time-nuts] OT: The tick-tock of the optical clock ....

[Bernd Neubig]

Hi David,

very similar work was done at PTB in Germany
http://www.ptb.de/en/aktuelles/archiv/presseinfos/pi2012/pitext/pi120301.html

... the charm of forbidden things...

Best regards

Bernd Neubig
AXTAL GmbH  Co. KG
www.axtal.com


- Original Message - 
From: David J Taylor david-tay...@blueyonder.co.uk

To: Time-nuts mailing list time-nuts@febo.com
Sent: Friday, April 27, 2012 11:30 AM
Subject: [time-nuts] OT: The tick-tock of the optical clock 



The tick-tock of the optical clock

NPL time scientists have made an accurate measurement of the highly 
forbidden octupole transition frequency in an ytterbium ion, which could 
be used as the basis for the next generation of optical atomic clocks - 
see:


 http://www.npl.co.uk/news/the-tick-tock-of-the-optical-clock

Cheers,
David
--
SatSignal software - quality software written to your requirements
Web:  http://www.satsignal.eu
Email:  david-tay...@blueyonder.co.uk

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Re: [time-nuts] OT: The tick-tock of the optical clock ....

[Bernd Neubig]

Rob,

you are right. My wording was not precise enough, sorry.
Regards

Bernd  DK1AG

AXTAL GmbH  Co. KG
www.axtal.com

- Original Message - 
From: Rob Kimberley robkimber...@btinternet.com
To: 'Discussion of precise time and frequency measurement' 
time-nuts@febo.com

Sent: Friday, April 27, 2012 4:45 PM
Subject: Re: [time-nuts] OT: The tick-tock of the optical clock 



I believe that NPL and PTB are working together on this project.

Rob Kimberley

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of David J Taylor
Sent: 27 April 2012 11:24
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] OT: The tick-tock of the optical clock 


Hi David,

very similar work was done at PTB in Germany
http://www.ptb.de/en/aktuelles/archiv/presseinfos/pi2012/pitext/pi1203
01.html

... the charm of forbidden things...

Best regards

Bernd Neubig


Danke,

David
--
SatSignal software - quality software written to your requirements
Web:  http://www.satsignal.eu
Email:  david-tay...@blueyonder.co.uk


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[time-nuts] Fw: WG: Tele Quarz Group OCXO

[Bernd Neubig]

Hi Detlef,

this item is not an OCXO but a TCXO.
Accoding to my memory the stability is +-0.3 ppm over about 0°C to +50°C, it 
has 5 V supply and a CMOS/TTL output
You can see the pin connections in the attachment (Option E). The trimmer is 20 
kOhm.
I wish you much fun with the part.

Best regards
Bernd, DK1AG
ex head of Tele Quarz oscillator division for 19 years ;)
now:
AXTAL GmbH  Co. KG
www.axtal.com




 

-Ursprüngliche Nachricht-
Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im
Auftrag von Detlef Twesten
Gesendet: Freitag, 2. März 2012 23:05
An: time-nuts@febo.com
Betreff: [time-nuts] Tele Quarz Group OCXO

Hi,
does someone know the TQTC 16-01A from Tele Quarz Group?
I'd like to get the Pinout and the supply voltage to help an radio amateur
in Germany.
He tried it with 5V and the standard pinout, pin 3 supply, pin 4 output and
pin 5 ground, but it doesn't work.
view from above
http://files.brauchmer.net/imghost/up/d2fe4104ad70678e793260f3e417e969.JPG
bottom view
http://files.brauchmer.net/imghost/up/60f17dc54947ca5fb5444d96c6b78bcf.JPG

Thanks in advance,
Detlef Twesten
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Re: [time-nuts] need example frequency vs temp equation

[Bernd Neubig]

Hi Jim,

There are different types of TCXO compensation techniques on the market.
Each of them generating a different style of f(T) characterisitcs.
Furthermore the f(T) response varies from unit to unit, because each TCXO is
usually uindividually compensated (or sometimes in groups of similar quartz
f(T) characteristics.
To name a few compensation types:
The classical types can be broken down in direct and indirect compensation:
1. the first one using a thermistor/capacitor/resistor network connected in
series to the quartz crystal resonator. This network represents a temprature
dependenta load caopacitants to the crystal.
2. the indirect ones using a thermistor/resistor network which generates a
temperature-dependent DC voltage, which is fed to a varactor diode (in
series to the crystal) and thus changing f over T. Sometimes the passive
network is combined with an op-amp to realize a higher voltage swing. 
3. The modern TCXO (all these small ceramic packaged SMD units) use IC-based
compensation techniques. There are different TCO on the market which differ
in their working principle slightly. But in general, most of those IC's
contain a temperature sensor, from which a DC voltage represented by
polynomial of 3rd or higher order is generated by analog techniqes:
The coefficients for the polynomial are 
- a0 = reference voltage
- a1 = outoput from temperature sensor
- a2 = output from temperature sensor multiplied by the same with an
analogue multiplier
- a3 = output of a2 multiplied with temp sensor output  etc.
These components are fed into an analogue summing amplifier through analogue
potentiometers, which are setting the magnitude of each coefficient.
This summed-up voltage ploynomial feeds one or two varactor diodes in series
to the crystal.
In the (still individual, but highly automated)compensation process, the
coefficient potentiometers are set set through a serial data line such, that
the f(T) characteristic shows minimum deviation over temperature. This
process runs through the whole operating temperture range in small
temperature steps, mostly in both directíons to take into account some of
the hysteresis of the crystal's f(T) characteristic.
4. Besides these techniques there are some other approaches, such like the
first generation of digitally compensated TCXO, which were using loo-up
tables for eacht temperature increment (bit), which contains the digital
word for the necessary compensation voltage. The disadvantage of this method
are the discontinuities between eacht temperature bit, causing small
frequency jumps and/or jitter

To conclude: Because of the individual process, TCXO do not show any uniform
f(T) characteristic. You can fit it by a higher order polynomial, but the
responses are looking different for each individual unit.


Best regards

Bernd, DK1AG

AXTAL GmbH  Co. KG
www.axtal.com 

-Ursprüngliche Nachricht-
Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im
Auftrag von Jim Lux
Gesendet: Donnerstag, 13. Oktober 2011 02:13
An: Discussion of precise time and frequency measurement
Betreff: [time-nuts] need example frequency vs temp equation

I'm putting together some examples of oscillator behavior vs temperature and
I'm looking for some plausible coefficients and simple equations to use to
generate nice looking curves.

oscillators are TCXO and run of the mill whatever they use for computer
clock oscillators (AT cut?).

Something that gives me decent PPM vs degrees C for a range from cold (-50
to -40) to hot (say +70 to +80)

I've got tons of measured data, but before I spent the time to try and do a
curve fit (implying that I can actually read the data and not have to copy
it by hand from a table or translate some oddball log file)

I've got Vig's tutorial: If you look at page 2-7, it's those curves I want
to generate.

(or if you look at 4-43 in the tutorial)

Maybe the Army book by Bennett?

Even better if I can replicate the hysteresis with a simple model.

I've got Frerking's equation
delta F/F = A1* deltaT + A2*deltaT^2 + A3*deltaT^3

deltaT = T - 25C

but what's some good numbers for A1, A2, and A3..  I found one reference
that cites Gerber and Ballato
A1 = -5.08E-6 * angle of cut relative to 35.25 degrees
A2 = -0.45E-9
A3 = 108.6E-12


that gets me a generic AT cut..

But what about TCXOs (which have more lumps in the curve...)



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Re: [time-nuts] OT: leaching was, Alternative time interval interpolation technique

[Bernd Neubig]

 
On Mon, 16 Aug 2010 17:53
Attila Kinali [att...@kinali.ch] wrote:

 Apropos Wenzel: Is there any distributor that sells them in single
quantities? Or do i have to get them from Wenzel directly?
 And is there any price list available?

You can buy ultra low phase noise OCXO (and smaller versions than Wenzel's)
in single quantities from
AXTAL www.axtal.com. We are selling directly to radio amateurs and time-nuts
from Germany to any destination country.
Professionals please go through our local reps.
For some OCXO listed on the website, phase not is not displayed on the data
sheet, but can be provided on request
Sorry for that commercial...  

 Why an OXCO? AFAIK the temperature has only an effect on long term
stability/drift, but doesn't affect short term effects (which cause the
jitters).  Or am i missing something?

Temperature has an important impact on short term stability in the range of
seconds and up, that's correct. However OCXO are usually using higher-Q
crystals (overtones, often SC-cuts), while VCXO, TCXO and clocks are mostly
using fundamental mode or low overtone crystals.

Bernd Neubig, DK1AG



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Re: [time-nuts] OT: leaching was, Alternative time interval interpolation technique

[Bernd Neubig]

On Aug 16, 2010, at 18:35 Said Jackson [saidj...@aol.com] wrote:

It's very hard to find a vendor making good (sc-cut) low PN crystals that
are not in an ocxo. They are mostly designed to work at inflection points
around 90C.
No good very low PN vcxos around unfortunately..

It is the nature (or definition) of the SC-cut that this cut yields an
inflection point at around 95°C. This makes it not usable for VCXO or clocks
without temperature control, becasue the frequency vs. temperature various
rather strongly in a normal -20C to +70C environment.
There are compromizes like the IT and the FC cut, whose inflection points
are at 75C or 50C respectively. But still the frequency excursion in
normal operating temperature ranges is rather large.

PN of VCXO is larger than that of OCXO because
- mostly fundamental mode or low overtone crystls are used, which have lower
Q that tose crystals used in OCXO
- the phase noise is increased due to parametric effects of teh varactor
diode
Nevertheless there are VCXO on the market which provide much lower phase
noise than teh mass-produced standard models.
See for example the AXIS10LN on the AXTAL website www.axtal.com. There may
be other vendors too ;-)

Regards

Bernd Neubig DK1AG



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