Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Bob kb8tq]

Hi

A thermistor has *no* output unless it is in a circuit that biases it up. A 
thermocouple
is the one that has an output when no bias is present….

Take a 10K thermistor and a 10K resistor and put them in series.  You will get 
roughly Vcc / 2 at 25C
at the junction of the two parts.. The output will change about 1.5% per 
degree. With a 5V Vcc, that’s 
around 38 mV/C. 

Bob

> On Jun 4, 2017, at 4:49 PM, Donald E. Pauly  wrote:
> 
> I own several Fluke 52 stereo thermometers with K themocouples.  They
> run 40 μV/C°.  All thermistors have tiny outputs without op amps.
> They also suffer from self heating.  AD590 sensors give AT LEAST 15
> mV/C° without op amps.  If a regulated 3,000V supply is available they
> can give 2 V/C° into a 1 Watt 10 Meg resistor.
> 
> πθ°μΩω±√·Γλ
> WB0KVV
> 
> 
> -- Forwarded message --
> From: Bob kb8tq 
> Date: Sun, Jun 4, 2017 at 11:46 AM
> Subject: Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies
> To: Discussion of precise time and frequency measurement 
> Cc: "rwa...@aol.com" , "Donald E. Pauly"
> 
> 
> 
> Hi
> 
> I think you have thermistors and thermocouples a bit mixed up. You can get
> quite substantial output voltages from a thermistor bridge….
> 
> Bob
> 
>> On Jun 4, 2017, at 11:44 AM, Donald E. Pauly  wrote:
>> 
>> I stand by my remark that thermistors have been obsolete for over 40
>> years.  The only exception that I know of is cesium beam tubes that
>> must withstand a 350° C bakeout.  Thermistors are unstable and
>> manufactured with a witches brew straight out of MacBeth.  Their
>> output voltages are tiny and are they inconvenient to use at different
>> temperatures.
>> 
>> Where did you get the idea to use a 1 k load for an AD590?  If you run
>> it from a -5 V supply you can use a 15 k load to a +5V supply.  This
>> gives 15 V/C° output.  If you drive it from a 10 Meg impedance current
>> source, you get 30,000 V/ C°.  If I remember correctly, I drove a
>> power MOSFET heater gate directly in my prototype oven 20 years ago.
>> It would go from full off to full on in 1/15 ° C.  Noise is 1/25,000 °
>> C in a 1 cycle bandwidth.
>> 
>> The room temperature coefficient of an AT crystal is -100 ppb per
>> reference cut angle in minutes.  (-600 ppb/C° for standard crystal)
>> The practical limit in a crystal designed for room temperature is
>> about 0.1' cut accuracy or ±10 ppb/C°.  If you have access to an
>> atomic standard, you can use feed forward to get ±1 ppb/C°.  If the
>> temperature can be held to ±0.001° C, this is ±1 part per trillion.
>> This kind of accuracy has never been heard of.  Feed forward also
>> allows you to incorporate the components of the oscillator into the
>> thermal behavior.  It does no good to have a perfect crystal if the
>> oscillator components drift.
>> 
>> πθ°μΩω±√·Γλ
>> WB0KVV
>> 
>> -- Forwarded message --
>> From: jimlux 
>> Date: Sun, Jun 4, 2017 at 4:47 AM
>> Subject: Re: [time-nuts] Fwd: HP5061B Versus HP5071 Cesium Line Frequencies
>> To: time-nuts@febo.com
>> 
>> 
>> On 6/3/17 9:56 PM, Donald E. Pauly wrote:
>> 
>>> It was only in the early 70s that Analog Devices invented the AD590
>>> solid state temperature sensor.  It made thermister bridges obsolete.
>> 
>> 
>> There is a difference between something like a platinum resistance
>> thermometer (PRT or RTD) and a thermistor, but they both are "measure
>> resistance to measure temperature" devices.
>> 
>> Yes, the AD590 is a useful part (I've got some in a device being
>> launched in August), but PRTs,thermistors, and thermocouples are still
>> widely used.
>> 
>> I don't know that the inherent precision (at room temperature)of the
>> various techniques is wildly different.  A 1mV/K signal (AD590 into a
>> 1k resistor) has to be measured to 0.1mV for 0.1 degree accuracy.
>> That's out of 300mV, so 1 part in 3000
>> 
>> A type E thermocouple is 1.495 mV at 25C and 1.801 at 30C, so about
>> 0.06 mV/K slope. Measure 0.006mV for 0.1 degree  (plus the "cold
>> junction" issue).  1 part in 250 measurement.
>> 
>> Modern RTDs all are 0.00385 ohm/ohm/degree at 25C.  Typically, you
>> have a 100 ohm device (although there are Pt1000s), so it's changing
>> 0.385 ohm/degree.  1 part in 3000
>> 
>> Checking the Omega catalog.. A 44007 has nominal 5k at 25C, and is
>> 4787 at 26C, so 1 part in 24.
>> 
>> Especially these days, with computers to deal with nonlinear
>> ca

Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[jimlux]

On 6/4/17 1:49 PM, Donald E. Pauly wrote:

I own several Fluke 52 stereo thermometers with K themocouples.  They
run 40 μV/C°.  All thermistors have tiny outputs without op amps.
They also suffer from self heating.  AD590 sensors give AT LEAST 15
mV/C° without op amps.  If a regulated 3,000V supply is available they
can give 2 V/C° into a 1 Watt 10 Meg resistor.


3kV?

That's an interesting concept. Better make sure you set your resistors 
up right and keep your temperature range limited, since the max voltage 
across the device is 30V.  And the power supply ripple had better be 
less than 1V (PSRR is 0.1 uA/V at 15V, and 0.5 uA/V at 5V).


What's the tempco of that resistor?

And, you know that the calibration error is +/- 0.5 degree (for the 
better M grade).. Yeah, it's repeatable to 0.1 degree (0.1 uA).







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[time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Donald E. Pauly]

I own several Fluke 52 stereo thermometers with K themocouples.  They
run 40 μV/C°.  All thermistors have tiny outputs without op amps.
They also suffer from self heating.  AD590 sensors give AT LEAST 15
mV/C° without op amps.  If a regulated 3,000V supply is available they
can give 2 V/C° into a 1 Watt 10 Meg resistor.

πθ°μΩω±√·Γλ
WB0KVV


-- Forwarded message --
From: Bob kb8tq 
Date: Sun, Jun 4, 2017 at 11:46 AM
Subject: Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies
To: Discussion of precise time and frequency measurement 
Cc: "rwa...@aol.com" , "Donald E. Pauly"



Hi

I think you have thermistors and thermocouples a bit mixed up. You can get
quite substantial output voltages from a thermistor bridge….

Bob

> On Jun 4, 2017, at 11:44 AM, Donald E. Pauly  wrote:
>
> I stand by my remark that thermistors have been obsolete for over 40
> years.  The only exception that I know of is cesium beam tubes that
> must withstand a 350° C bakeout.  Thermistors are unstable and
> manufactured with a witches brew straight out of MacBeth.  Their
> output voltages are tiny and are they inconvenient to use at different
> temperatures.
>
> Where did you get the idea to use a 1 k load for an AD590?  If you run
> it from a -5 V supply you can use a 15 k load to a +5V supply.  This
> gives 15 V/C° output.  If you drive it from a 10 Meg impedance current
> source, you get 30,000 V/ C°.  If I remember correctly, I drove a
> power MOSFET heater gate directly in my prototype oven 20 years ago.
> It would go from full off to full on in 1/15 ° C.  Noise is 1/25,000 °
> C in a 1 cycle bandwidth.
>
> The room temperature coefficient of an AT crystal is -100 ppb per
> reference cut angle in minutes.  (-600 ppb/C° for standard crystal)
> The practical limit in a crystal designed for room temperature is
> about 0.1' cut accuracy or ±10 ppb/C°.  If you have access to an
> atomic standard, you can use feed forward to get ±1 ppb/C°.  If the
> temperature can be held to ±0.001° C, this is ±1 part per trillion.
> This kind of accuracy has never been heard of.  Feed forward also
> allows you to incorporate the components of the oscillator into the
> thermal behavior.  It does no good to have a perfect crystal if the
> oscillator components drift.
>
> πθ°μΩω±√·Γλ
> WB0KVV
>
> -- Forwarded message --
> From: jimlux 
> Date: Sun, Jun 4, 2017 at 4:47 AM
> Subject: Re: [time-nuts] Fwd: HP5061B Versus HP5071 Cesium Line Frequencies
> To: time-nuts@febo.com
>
>
> On 6/3/17 9:56 PM, Donald E. Pauly wrote:
>
>> It was only in the early 70s that Analog Devices invented the AD590
>> solid state temperature sensor.  It made thermister bridges obsolete.
>
>
> There is a difference between something like a platinum resistance
> thermometer (PRT or RTD) and a thermistor, but they both are "measure
> resistance to measure temperature" devices.
>
> Yes, the AD590 is a useful part (I've got some in a device being
> launched in August), but PRTs,thermistors, and thermocouples are still
> widely used.
>
> I don't know that the inherent precision (at room temperature)of the
> various techniques is wildly different.  A 1mV/K signal (AD590 into a
> 1k resistor) has to be measured to 0.1mV for 0.1 degree accuracy.
> That's out of 300mV, so 1 part in 3000
>
> A type E thermocouple is 1.495 mV at 25C and 1.801 at 30C, so about
> 0.06 mV/K slope. Measure 0.006mV for 0.1 degree  (plus the "cold
> junction" issue).  1 part in 250 measurement.
>
> Modern RTDs all are 0.00385 ohm/ohm/degree at 25C.  Typically, you
> have a 100 ohm device (although there are Pt1000s), so it's changing
> 0.385 ohm/degree.  1 part in 3000
>
> Checking the Omega catalog.. A 44007 has nominal 5k at 25C, and is
> 4787 at 26C, so 1 part in 24.
>
> Especially these days, with computers to deal with nonlinear
> calibration curves, there's an awful lot of TCs and Thermistors in
> use. The big advantage of the AD590 and PRT is that they are basically
> linear over a convenient temperature range.
>
> In a variety applications, other aspects of the measurement device are
> important - ESD sensitivity, tolerance to wildly out of spec
> temperature without damage, radiation effects etc.  Not an issue here,
> but I'll note that the thermistor, PRT, and thermocouple are
> essentially ESD immune. The AD590 most certainly is not.
>
> If you go out and buy cheap industrial PID temperature controller it
> will have input modes for various thermocouples and PRTs.  I suppose
> there's probably some that take 1uA/K, but it's not something I would
> expect.
>
> So I wouldn't say thermistor bridges (or other 

Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Bob kb8tq]

Hi

I think you have thermistors and thermocouples a bit mixed up. You can get
quite substantial output voltages from a thermistor bridge….

Bob

> On Jun 4, 2017, at 11:44 AM, Donald E. Pauly  wrote:
> 
> I stand by my remark that thermistors have been obsolete for over 40
> years.  The only exception that I know of is cesium beam tubes that
> must withstand a 350° C bakeout.  Thermistors are unstable and
> manufactured with a witches brew straight out of MacBeth.  Their
> output voltages are tiny and are they inconvenient to use at different
> temperatures.
> 
> Where did you get the idea to use a 1 k load for an AD590?  If you run
> it from a -5 V supply you can use a 15 k load to a +5V supply.  This
> gives 15 V/C° output.  If you drive it from a 10 Meg impedance current
> source, you get 30,000 V/ C°.  If I remember correctly, I drove a
> power MOSFET heater gate directly in my prototype oven 20 years ago.
> It would go from full off to full on in 1/15 ° C.  Noise is 1/25,000 °
> C in a 1 cycle bandwidth.
> 
> The room temperature coefficient of an AT crystal is -100 ppb per
> reference cut angle in minutes.  (-600 ppb/C° for standard crystal)
> The practical limit in a crystal designed for room temperature is
> about 0.1' cut accuracy or ±10 ppb/C°.  If you have access to an
> atomic standard, you can use feed forward to get ±1 ppb/C°.  If the
> temperature can be held to ±0.001° C, this is ±1 part per trillion.
> This kind of accuracy has never been heard of.  Feed forward also
> allows you to incorporate the components of the oscillator into the
> thermal behavior.  It does no good to have a perfect crystal if the
> oscillator components drift.
> 
> πθ°μΩω±√·Γλ
> WB0KVV
> 
> -- Forwarded message --
> From: jimlux 
> Date: Sun, Jun 4, 2017 at 4:47 AM
> Subject: Re: [time-nuts] Fwd: HP5061B Versus HP5071 Cesium Line Frequencies
> To: time-nuts@febo.com
> 
> 
> On 6/3/17 9:56 PM, Donald E. Pauly wrote:
> 
>> It was only in the early 70s that Analog Devices invented the AD590
>> solid state temperature sensor.  It made thermister bridges obsolete.
> 
> 
> There is a difference between something like a platinum resistance
> thermometer (PRT or RTD) and a thermistor, but they both are "measure
> resistance to measure temperature" devices.
> 
> Yes, the AD590 is a useful part (I've got some in a device being
> launched in August), but PRTs,thermistors, and thermocouples are still
> widely used.
> 
> I don't know that the inherent precision (at room temperature)of the
> various techniques is wildly different.  A 1mV/K signal (AD590 into a
> 1k resistor) has to be measured to 0.1mV for 0.1 degree accuracy.
> That's out of 300mV, so 1 part in 3000
> 
> A type E thermocouple is 1.495 mV at 25C and 1.801 at 30C, so about
> 0.06 mV/K slope. Measure 0.006mV for 0.1 degree  (plus the "cold
> junction" issue).  1 part in 250 measurement.
> 
> Modern RTDs all are 0.00385 ohm/ohm/degree at 25C.  Typically, you
> have a 100 ohm device (although there are Pt1000s), so it's changing
> 0.385 ohm/degree.  1 part in 3000
> 
> Checking the Omega catalog.. A 44007 has nominal 5k at 25C, and is
> 4787 at 26C, so 1 part in 24.
> 
> Especially these days, with computers to deal with nonlinear
> calibration curves, there's an awful lot of TCs and Thermistors in
> use. The big advantage of the AD590 and PRT is that they are basically
> linear over a convenient temperature range.
> 
> In a variety applications, other aspects of the measurement device are
> important - ESD sensitivity, tolerance to wildly out of spec
> temperature without damage, radiation effects etc.  Not an issue here,
> but I'll note that the thermistor, PRT, and thermocouple are
> essentially ESD immune. The AD590 most certainly is not.
> 
> If you go out and buy cheap industrial PID temperature controller it
> will have input modes for various thermocouples and PRTs.  I suppose
> there's probably some that take 1uA/K, but it's not something I would
> expect.
> 
> So I wouldn't say thermistor bridges (or other temperature
> measurements) are obsolete.
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Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Bob kb8tq]

Hi

Ok, when you wrote the specification for your crystals what was the tolerance 
on the angle
for those crystals? What did the suppliers who quoted to your spec say about 
the angle tolerance 
you specified? When they shipped against your volume requirements how did they 
do against the 
specification? When your incoming QA tested the crystals what did they find? 
When you put the 
crystals into production oscillators and tested the result how did they 
perform? 

Bob


> On Jun 4, 2017, at 11:09 AM, Donald E. Pauly  wrote:
> 
> I've bought dozens of them over the years and talked to crystal
> engineers for tens of hours.  I watched them plated and tuned at a
> crystal filter company in Phoenix.  I own Virgil Bottom's book on the
> subject and understood half of it.
> 
> πθ°μΩω±√·Γλ
> WB0KVV
> 
> 
> -- Forwarded message --
> From: Bob kb8tq 
> Date: Sun, Jun 4, 2017 at 5:15 AM
> Subject: Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies
> To: Discussion of precise time and frequency measurement 
> Cc: "rwa...@aol.com" , "Donald E. Pauly"
> 
> 
> 
> Hi
> 
> Have you ever tried to actually *buy* a crystal built to a
> specification? There is a
> tolerance on them. That has a profound impact on what you can *buy*.
> 
> Bob
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Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Bob kb8tq]

Hi

Have you ever tried to actually *buy* a crystal built to a specification? There 
is a 
tolerance on them. That has a profound impact on what you can *buy*. 

Bob


> On Jun 4, 2017, at 12:56 AM, Donald E. Pauly  wrote:
> 
> You have a fundamental misunderstanding of the AT curve family.  See
> my QBASIC plot at
> http://gonascent.com/papers/hp/hp5061/photos/newxtl.jpg .  The
> commonly described AT cut is shown as the largest sine wave in the
> blue rectangle.  The left side of the rectangle is -55°C, the center
> is 25° C and the right side is 105° C.  The bottom of the rectangle is
> -16 ppm and the top is +16 ppm.
> 
> Main Cut
> Temp   Freq
> -55° C -16 ppm
> -15° C +16 ppm
> +25° C ±0 ppm
> +65° C -16 ppm
> 105° C +16 ppm
> 
> You can get a lower turnover point of 24° C and an upper turnover
> point of 26° C. Their amplitude would be °±0.250 ppb.  As the turnover
> points approach each other, their amplitude approaches zero.  The line
> joining all the turnover points is y= -8·x^3.  The zero temperature
> for 25° is y=4·x^3.  Practical tolerance these days is on the order of
> 0.1 minutes of arc.  This is within the width of the traces in the
> graph.
> 
> You are way off on your 0° to 50° C crystal.
> 
> ["Umm …. errr … it’s quite easy to get a +/- 2 ppm 0-50C AT cut
> *including* the tolerance on the cut angle."]
> 
> Temp   Freq
> 0° C   -0.488 ppb (lower limit)
> 12.5° C  +0.488 ppb (lower turning point)
>   25° C  ±0
> 37.5° C  -0.488 ppb (upper turning point)
>   50° C +0.488 ppb (upper limit)
> 
> As I claimed, a Thermal Electric Cooler has never been used to build a
> crystal oscillator.  In the 50s, TEC efficiencies were on the order of
> 1% and were useless.  The Soviets made coolers more practical in the
> 70s with better materials.  I saw one used at Telemation that was able
> to measure dew point by condensing water vapor on a mirror.  It looks
> like efficiencies have now improved to 33% or so.
> 
> It was only in the early 70s that Analog Devices invented the AD590
> solid state temperature sensor.  It made thermister bridges obsolete.
> Switching amplifiers are required to drive thermal coolers if you want
> to preserve efficiency.
> 
> πθ°μΩω±√·Γλ
> WB0KVV
> 
> -- Forwarded message --
> From: Bob kb8tq 
> Date: Fri, Jun 2, 2017 at 12:22 PM
> Subject: Re: HP5061B Versus HP5071 Cesium Line Frequencies
> To: "Donald E. Pauly" 
> Cc: "rwa...@aol.com" , time-nuts 
> 
> Hi
> 
> Any real crystal you buy will have a tolerance on the angle. In the
> case of a crystal cut for turn the temperature will be a bit different
> and you will match your oven to it. If you attempt a zero angle cut,
> you will never really hit it and there is no way to compensate for the
> problem.
> 
> Bob
> 
> On Jun 2, 2017, at 3:19 PM, Donald E. Pauly  wrote:
> 
> A cut at that angle has no turn over temperature. The zero temperature
> coefficient point is 25°.  Its temperature coefficient everywhere else
> is positive.
> 
> On Friday, June 2, 2017, Bob kb8tq  wrote:
>> 
>> Hi
>> 
>> If you are going to use an oven, it’s better to run it at the turn 
>> temperature of
>> the crystal. That would put you above 50C for an AT and a bit higher still 
>> for an SC.
>> 
>> Bob
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Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[jimlux]

On 6/3/17 5:54 PM, Bob kb8tq wrote:

Hi

The objective of the early work with coolers and OCXO’s was DOD sponsored. Low 
cost was
not the goal :) The idea was that aging might be much better at the lower turn 
than at the upper turn. Once they
played around a bit they found that activation energy was a real thing in this 
case. The improvement in aging
did not justify the significant increase in complexity of the design. The idea 
has popped up about every ten
years. Each time the conclusion after building a trial unit is pretty much the 
same.




I'm just picturing in my mind a 14 inch high rack mount unit with 
several hundred watts in heater power for the vacuum tube amplifiers, 
etc. needed to implement this kind of thing in the early 50s.


I'll bet someone also built one with mechanical refrigeration, a liquid 
cooling loop, and an electronic heater.  That one was a full rack 
cabinet


The "idea popping up every 10 years" is not restricted to crystal 
oscillators.  Anything where there's a "the technology doesn't support 
it" is the barrier. A couple generations and all of a sudden you can do 
it.  And sometimes it works - DDS and PN codes are examples of things 
which were barely feasible some decades ago, so people went through all 
sorts of gyrations to achieve goals with out it, but now, it's "oh yeah, 
sure, a parallel correlator to acquire and track 32 simultaneous GPS 
signals, isn't there an Arduino Sketch for that?"



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Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Bob kb8tq]

Hi

The objective of the early work with coolers and OCXO’s was DOD sponsored. Low 
cost was
not the goal :) The idea was that aging might be much better at the lower turn 
than at the upper turn. Once they
played around a bit they found that activation energy was a real thing in this 
case. The improvement in aging
did not justify the significant increase in complexity of the design. The idea 
has popped up about every ten 
years. Each time the conclusion after building a trial unit is pretty much the 
same. 

Bob

> On Jun 3, 2017, at 8:18 PM, jimlux  wrote:
> 
> On 6/3/17 2:38 PM, Poul-Henning Kamp wrote:
>> 
>> In message 
>> 
>> , "Donald E. Pauly" writes:
>> 
>>> Electronic thermal coolers did not exist then
>> 
>> http://www.thermoelectrics.caltech.edu/thermoelectrics/history.html
> 
> I'm not sure about fancy coolers.. Yeah, people showed that the effect 
> worked, but I think they really didn't come into their own until the modern 
> ones that are omnipresent in 12V powered beer coolers and the like were 
> developed.  That was 70s according to the article.
> Borg Warner (of clutch, brake, and gearbox fame) apparently had one in 1960.
> http://www.thermoelectric.com/2010/archives/library/Ads%20in%20the%2060's.PDF
> 
> So they existed, but were pretty exotic. would a crystal oscillator builder 
> have wanted to fool with one?  Hey, there have been people tinkering with 
> almost everything forever.
> 
> 
>> 
>>> Electronic temperature sensors did not exist either.
>> 
>> https://en.wikipedia.org/wiki/Resistance_thermometer#History
>> 
> 
> Yep... and thermocouples have been used for thermometry for a long time too. 
> Thermistors, for that matter, nonlinear as all get-out, but readily available.
> 
> In the 50s, a *transistor* oscillator would have been pretty unusual. I'm not 
> sure they could work at a high enough frequency.  You'll note that the early 
> "transistor radios" were basically TRF designs for the AM band, and the 
> transistor basically provided audio gain, not RF gain.
> 
> http://www.junkbox.com/electronics/sheets/GE_2N107_Datasheet.jpg
> 
> I guess the regen receiver must have had some gain at 1 MHz. I found an old 
> GE datasheet that gives the ft of 0.6 MHz. (and the hfe wasn't bad, 20, at 
> DC, probably)
> 
> But you sure weren't building a 5MHz or 10 MHz oscillator with a 2N107 or a 
> CK722.  Or the 2N170 NPN, which I am surprised to find you can still buy (and 
> cheaper, in constant dollars, than originally).
> 
> 
> 
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Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Bob kb8tq]

Hi

A bit of “who knew what when” as far as crystal cuts:

1931:

http://www.worldcat.org/title/quartz-resonators-and-oscillators/oclc/11299952 


1946:

https://www.amazon.com/Piezoelectricity-Introduction-Applications-Electromechanical-Phenomena/dp/B000OJWIJS/ref=sr_1_1?s=books&ie=UTF8&qid=1496534218&sr=1-1&keywords=Piezoelectricity

1956:

http://www.tubebooks.org/Books/hpc.pdf 

The only one I could find online is the last one, sorry about that !! It’s also 
a fun read if you happen to be into 1950’s radio technology. 

Bob


> On Jun 3, 2017, at 5:38 PM, Poul-Henning Kamp  wrote:
> 
> 
> In message 
> 
> , "Donald E. Pauly" writes:
> 
>> Electronic thermal coolers did not exist then 
> 
> http://www.thermoelectrics.caltech.edu/thermoelectrics/history.html
> 
>> Electronic temperature sensors did not exist either.
> 
> https://en.wikipedia.org/wiki/Resistance_thermometer#History
> 
> -- 
> Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
> p...@freebsd.org | TCP/IP since RFC 956
> FreeBSD committer   | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.
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Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Bob kb8tq]

Hi




> On Jun 2, 2017, at 7:45 PM, Donald E. Pauly  wrote:
> 
> https://www.febo.com/pipermail/time-nuts/2017-May/105566.html 
> <https://www.febo.com/pipermail/time-nuts/2017-May/105566.html>

Ok, so yet again a reference to the start of this thread … why?

> 
> Electronic thermal coolers did not exist then so it could not be done.
> Electronic temperature sensors did not exist either.

I guess they must have just dreamed up the pelter devices they used. FYI, they 
have
been around since 1834 (no that’s not a typo). 

>  That crystal cut
> has been known since the 1940's at least.

And once you get away from an AT or SC, how much is known about the mode 
spectra of 
the cut ….

>  It has been neglected
> because of limited temperature range. It yields ±1 ppm over a range of
> ±20° C from 25° C.  A slightly different angle of cut can yield ±250
> ppb over that range. (4:1 improvement) Contrast that with a normal AT
> cut which yields ±9 ppm over that range.

Umm …. errr … it’s quite easy to get a +/- 2 ppm 0-50C AT cut *including* the 
tolerance
on the cut angle.

> 
> I built an oven with an Analog Devices temperature sensor 20 years
> ago.  I did not have time to incorporate foam insulation.  The heater
> power was not available to run it at 65° C without insulation.  It had
> to run at 40° C and it would hold about 1 ppb over a few hours.   It
> would hold the crystal within 0.01° or so but it was far away from the
> turnover temperature.   Convection currents cause problems.  It
> convinced me that ovens were headaches.   Thermal coolers remove most
> of these.

I’d suggest you try a few more experiments with real crystals in real 
applications. 

Bob

> 
> πθ°μΩω±√·Γ
> WB0KVV
> 
> -- Forwarded message --
> From: Bob kb8tq 
> Date: Fri, Jun 2, 2017 at 3:50 PM
> Subject: Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies
> To: Discussion of precise time and frequency measurement 
> Cc: "rwa...@aol.com" , "Donald E. Pauly"
> 
> 
> 
> Hi
> 
> Have you checked out the papers from the 1950 and `1960’s where they
> actually tried what you
> propose with essentially the same parts you are looking at using?
> 
> Bob
> 
> 
>> On Jun 2, 2017, at 5:51 PM, Donald E. Pauly  wrote:
>> 
>> # 2 is not true.  A cut has either two turning points or zero.  Where
>> both turning points exist there are two temperatures at which the
>> temperature coefficient of frequency is zero.  Cut 0 on figure 6 at
>> https://coloradocrystal.com/applications has no turnover point.  It is
>> neither fish nor fowl.  Cut 6 is the normal AT curve with extremes of
>> ±16 ppm for -55° C thru +105° C.  All curves normally intersect at 25°
>> C rather than the 27° C shown.  25° C is half way between -55° C thru
>> +105° C.  Curve 6 is the Tchebychev polynomial y=4x^3-3x and curve 0
>> is y=4x^3.
>> 
>> Consider the standard AT cut which has turnover points at -15° C and
>> 65° C.  The lower turnover would ordinarily not be used in ovens.  A
>> set point error of ±1° C in the upper turnover point at 65° C results
>> in a frequency error of +14.875·10^-9.  For cut 0, that same ±1° error
>> in room temperature results in a frequency error of  ±31.25·10^-12.
>> This is an improvement of 476 to 1.  You apparently have not thought
>> thru what improvements are possible with thermal coolers/heaters.
>> Among these is near instant warm up and greatly reduced power for
>> thermal management.
>> 
>> πθ°μΩω±√·Γ
>> WB0KVV
>> 
>> On Friday, June 2, 2017, Bob kb8tq  wrote:
>>> 
>>> Hi
>>> 
>>> Any real crystal you buy will have a tolerance on the angle. In the case of 
>>> a crystal cut for turn
>>> the temperature will be a bit different and you will match your oven to it. 
>>> If you attempt a zero
>>> angle cut, you will never really hit it and there is no way to compensate 
>>> for the problem.
>>> 
>>> Bob
>>> 
>> ___
>> time-nuts mailing list -- time-nuts@febo.com
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>> and follow the instructions there.
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Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Bob kb8tq]

> On Jun 2, 2017, at 7:45 PM, Donald E. Pauly  wrote:
> 
> https://www.febo.com/pipermail/time-nuts/2017-May/105566.html
> 
> Electronic thermal coolers did not exist then so it could not be done.
> Electronic temperature sensors did not exist either.  That crystal cut
> has been known since the 1940's at least.  It has been neglected
> because of limited temperature range. It yields ±1 ppm over a range of
> ±20° C from 25° C.  A slightly different angle of cut can yield ±250
> ppb over that range. (4:1 improvement) Contrast that with a normal AT
> cut which yields ±9 ppm over that range.
> 
> I built an oven with an Analog Devices temperature sensor 20 years
> ago.  I did not have time to incorporate foam insulation.  The heater
> power was not available to run it at 65° C without insulation.  It had
> to run at 40° C and it would hold about 1 ppb over a few hours.   It
> would hold the crystal within 0.01° or so but it was far away from the
> turnover temperature.   Convection currents cause problems.  It
> convinced me that ovens were headaches.   Thermal coolers remove most
> of these.
> 
> πθ°μΩω±√·Γ
> WB0KVV
> 
> -- Forwarded message ------
> From: Bob kb8tq 
> Date: Fri, Jun 2, 2017 at 3:50 PM
> Subject: Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies
> To: Discussion of precise time and frequency measurement 
> Cc: "rwa...@aol.com" , "Donald E. Pauly"
> 
> 
> 
> Hi
> 
> Have you checked out the papers from the 1950 and `1960’s where they
> actually tried what you
> propose with essentially the same parts you are looking at using?
> 
> Bob
> 
> 
>> On Jun 2, 2017, at 5:51 PM, Donald E. Pauly  wrote:
>> 
>> # 2 is not true.  A cut has either two turning points or zero.  Where
>> both turning points exist there are two temperatures at which the
>> temperature coefficient of frequency is zero.  Cut 0 on figure 6 at
>> https://coloradocrystal.com/applications has no turnover point.  It is
>> neither fish nor fowl.  Cut 6 is the normal AT curve with extremes of
>> ±16 ppm for -55° C thru +105° C.  All curves normally intersect at 25°
>> C rather than the 27° C shown.  25° C is half way between -55° C thru
>> +105° C.  Curve 6 is the Tchebychev polynomial y=4x^3-3x and curve 0
>> is y=4x^3.
>> 
>> Consider the standard AT cut which has turnover points at -15° C and
>> 65° C.  The lower turnover would ordinarily not be used in ovens.  A
>> set point error of ±1° C in the upper turnover point at 65° C results
>> in a frequency error of +14.875·10^-9.  For cut 0, that same ±1° error
>> in room temperature results in a frequency error of  ±31.25·10^-12.
>> This is an improvement of 476 to 1.  You apparently have not thought
>> thru what improvements are possible with thermal coolers/heaters.
>> Among these is near instant warm up and greatly reduced power for
>> thermal management.
>> 
>> πθ°μΩω±√·Γ
>> WB0KVV
>> 
>> On Friday, June 2, 2017, Bob kb8tq  wrote:
>>> 
>>> Hi
>>> 
>>> Any real crystal you buy will have a tolerance on the angle. In the case of 
>>> a crystal cut for turn
>>> the temperature will be a bit different and you will match your oven to it. 
>>> If you attempt a zero
>>> angle cut, you will never really hit it and there is no way to compensate 
>>> for the problem.
>>> 
>>> Bob
>>> 
>> ___
>> time-nuts mailing list -- time-nuts@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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Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Tom Van Baak]

> A guy by the name of David W. Allan used direct multiplication to
> build NBS-4 and NBS-5, see http://tf.nist.gov/general/pdf/65.pdf .  He
> didn't see anything wrong with it.  He used a commercial frequency
> standard modified from 5 mc to 5.006880 mc.

That kind of LO is ok for a research clock. But maybe not so good for a working 
institutional or house standard where people expect frequency distribution in 
nice round numbers like 5 or 10 or 100 MHz.

The good news is that you can get a perfect 1PPS out of it: divide by 5006880 = 
2^5 * 3^3 * 5 * 19 * 61. I've heard JohnA has one of these vintage 5.006880 mc 
oscillators so I did a PIC divider for him. See pd21 under 
www.leapsecond.com/pic/src/

/tvb

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[time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Donald E. Pauly]

https://www.febo.com/pipermail/time-nuts/2017-May/105566.html

Tell us more about the RF leakage problems in the 5061.  I thought
that the 5071 used the same beam tube.  How does the electricity leak
out and at what frequencies?My method costs a tenth as much and
has higher spectral purity performance to the beam tube.  I admit that
I hadn't thought about the electricity leaking out. Can the leak be
plugged?

BTW these are not strictly Diophantine equations.  No exact solution
is possible if C field is to be used.  Can you tell us the magic
numbers?

πθ°μΩω±√·Γλ
WB0KV


-- Forwarded message --
From: Richard (Rick) Karlquist 
Date: Fri, Jun 2, 2017 at 12:10 PM
Subject: Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies
To: Discussion of precise time and frequency measurement
, "Donald E. Pauly" ,
"rwa...@aol.com" 


I said no *manufacturer* does it this way.  NBS is not
a manufacturer.  In a one-off money-is-no-object non-portable
standard, you can make direct multiplication work.  It
will not work well in a 5061, because of RF leakage
issues specific to the 5061 that are well documented.
Bolting on a different synthesizer does nothing to change that.

The decision not to use direct multiplication has nothing to
do with not being able to figure out how to synthesize the
correct frequency.  Certainly by the time we did the 5071A,
we were already using DDS, and it wouldn't have been any
problem to synthesize for direct multiplication if we had
wanted to do that.  You seem to be doing it the hard way
(pre DDS) involving Diophantine equations.  So it's easier
to do direct multiply than it used to be, but that doesn't
necessarily mean you should do it that way.

Rick
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Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Bob kb8tq]

Hi

Have you checked out the papers from the 1950 and `1960’s where they actually 
tried what you 
propose with essentially the same parts you are looking at using?

Bob


> On Jun 2, 2017, at 5:51 PM, Donald E. Pauly  wrote:
> 
> # 2 is not true.  A cut has either two turning points or zero.  Where
> both turning points exist there are two temperatures at which the
> temperature coefficient of frequency is zero.  Cut 0 on figure 6 at
> https://coloradocrystal.com/applications has no turnover point.  It is
> neither fish nor fowl.  Cut 6 is the normal AT curve with extremes of
> ±16 ppm for -55° C thru +105° C.  All curves normally intersect at 25°
> C rather than the 27° C shown.  25° C is half way between -55° C thru
> +105° C.  Curve 6 is the Tchebychev polynomial y=4x^3-3x and curve 0
> is y=4x^3.
> 
> Consider the standard AT cut which has turnover points at -15° C and
> 65° C.  The lower turnover would ordinarily not be used in ovens.  A
> set point error of ±1° C in the upper turnover point at 65° C results
> in a frequency error of +14.875·10^-9.  For cut 0, that same ±1° error
> in room temperature results in a frequency error of  ±31.25·10^-12.
> This is an improvement of 476 to 1.  You apparently have not thought
> thru what improvements are possible with thermal coolers/heaters.
> Among these is near instant warm up and greatly reduced power for
> thermal management.
> 
> πθ°μΩω±√·Γ
> WB0KVV
> 
> -- Forwarded message --
> From: Bob kb8tq 
> Date: Fri, Jun 2, 2017 at 12:43 PM
> Subject: Re: HP5061B Versus HP5071 Cesium Line Frequencies
> To: "Donald E. Pauly" 
> 
> Hi
> 
> Which statement is not true:
> 
> 1) That there is a tolerance on the cut angle of a crystal?
> 
> 2) That true zero temperature coefficient only happens at the turn?
> 
> 3) That heater based controllers are impossible to build?
> 
> Bob
> 
> On Jun 2, 2017, at 3:40 PM, Donald E. Pauly  wrote:
> 
> That is not true.  I say that thermal coolers have made ovens
> obsolete.  A zero temperature coefficient at room temperature is
> easier to hit than a zero temperature at the upper turnover point when
> such a thing exists.  See
> curve 0 in Figure 6 at https://coloradocrystal.com/applications/ .
> 
> πθ°μΩω±√·Γ
> WB0KVV
> 
> 
> On Friday, June 2, 2017, Bob kb8tq  wrote:
>> 
>> Hi
>> 
>> Any real crystal you buy will have a tolerance on the angle. In the case of 
>> a crystal cut for turn
>> the temperature will be a bit different and you will match your oven to it. 
>> If you attempt a zero
>> angle cut, you will never really hit it and there is no way to compensate 
>> for the problem.
>> 
>> Bob
>> 
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Bob kb8tq]

Hi

How many OCXO’s have you actually built?

Bob

> On Jun 2, 2017, at 5:51 PM, Donald E. Pauly  wrote:
> 
> # 2 is not true.  A cut has either two turning points or zero.  Where
> both turning points exist there are two temperatures at which the
> temperature coefficient of frequency is zero.  Cut 0 on figure 6 at
> https://coloradocrystal.com/applications has no turnover point.  It is
> neither fish nor fowl.  Cut 6 is the normal AT curve with extremes of
> ±16 ppm for -55° C thru +105° C.  All curves normally intersect at 25°
> C rather than the 27° C shown.  25° C is half way between -55° C thru
> +105° C.  Curve 6 is the Tchebychev polynomial y=4x^3-3x and curve 0
> is y=4x^3.
> 
> Consider the standard AT cut which has turnover points at -15° C and
> 65° C.  The lower turnover would ordinarily not be used in ovens.  A
> set point error of ±1° C in the upper turnover point at 65° C results
> in a frequency error of +14.875·10^-9.  For cut 0, that same ±1° error
> in room temperature results in a frequency error of  ±31.25·10^-12.
> This is an improvement of 476 to 1.  You apparently have not thought
> thru what improvements are possible with thermal coolers/heaters.
> Among these is near instant warm up and greatly reduced power for
> thermal management.
> 
> πθ°μΩω±√·Γ
> WB0KVV
> 
> -- Forwarded message --
> From: Bob kb8tq 
> Date: Fri, Jun 2, 2017 at 12:43 PM
> Subject: Re: HP5061B Versus HP5071 Cesium Line Frequencies
> To: "Donald E. Pauly" 
> 
> Hi
> 
> Which statement is not true:
> 
> 1) That there is a tolerance on the cut angle of a crystal?
> 
> 2) That true zero temperature coefficient only happens at the turn?
> 
> 3) That heater based controllers are impossible to build?
> 
> Bob
> 
> On Jun 2, 2017, at 3:40 PM, Donald E. Pauly  wrote:
> 
> That is not true.  I say that thermal coolers have made ovens
> obsolete.  A zero temperature coefficient at room temperature is
> easier to hit than a zero temperature at the upper turnover point when
> such a thing exists.  See
> curve 0 in Figure 6 at https://coloradocrystal.com/applications/ .
> 
> πθ°μΩω±√·Γ
> WB0KVV
> 
> 
> On Friday, June 2, 2017, Bob kb8tq  wrote:
>> 
>> Hi
>> 
>> Any real crystal you buy will have a tolerance on the angle. In the case of 
>> a crystal cut for turn
>> the temperature will be a bit different and you will match your oven to it. 
>> If you attempt a zero
>> angle cut, you will never really hit it and there is no way to compensate 
>> for the problem.
>> 
>> Bob
>> 
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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[time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Donald E. Pauly]

That is not true.  I say that thermal coolers have made ovens obsolete.  A
zero temperature coefficient at room temperature is easier to hit than a
zero temperature at the upper turnover point when such a thing exists.  See
curve 0 in Figure 6 at https://coloradocrystal.com/applications/ .

πθ°μΩω±√·Γ
WB0KVV


On Friday, June 2, 2017, Bob kb8tq > wrote:

> Hi
>
> Any real crystal you buy will have a tolerance on the angle. In the case
> of a crystal cut for turn
> the temperature will be a bit different and you will match your oven to
> it. If you attempt a zero
> angle cut, you will never really hit it and there is no way to compensate
> for the problem.
>
> Bob
>
> On Jun 2, 2017, at 3:19 PM, Donald E. Pauly 
> wrote:
>
> A cut at that angle has no turn over temperature. The zero temperature
> coefficient point is 25°.  Its temperature coefficient everywhere else is
> positive.
>
> On Friday, June 2, 2017, Bob kb8tq  wrote:
>
>> Hi
>>
>> If you are going to use an oven, it’s better to run it at the turn
>> temperature of
>> the crystal. That would put you above 50C for an AT and a bit higher
>> still for an SC.
>>
>> Bob
>>
>>
>
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[time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Donald E. Pauly]

A cut at that angle has no turn over temperature. The zero temperature
coefficient point is 25°.  Its temperature coefficient everywhere else is
positive.

On Friday, June 2, 2017, Bob kb8tq  wrote:

> Hi
>
> If you are going to use an oven, it’s better to run it at the turn
> temperature of
> the crystal. That would put you above 50C for an AT and a bit higher still
> for an SC.
>
> Bob
>
> > On Jun 2, 2017, at 2:09 PM, Donald E. Pauly  > wrote:
> >
> > https://www.febo.com/pipermail/time-nuts/2017-May/105566.html
> >
> > If we build this circuit it would be a bench model not designed to be
> > inside a hot chassis.  It would be able to lock ± 5° C of 25° C.  My
> > idea of an oven is to keep the crystal and oscillator at 25° C ±0.001
> > °C with 60 second warm up/cool down time.
> >
> > πθ°μΩω±√·Γλ
> > WB0KVV
> >
> > -- Forwarded message ------
> > From: Bob kb8tq >
> > Date: Fri, Jun 2, 2017 at 5:57 AM
> > Subject: Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies
> > To: Discussion of precise time and frequency measurement <
> time-nuts@febo.com >
> >
> > Hi
> >
> > I would suggest you check a few real crystals over the 20 to 40C range ….
> > With all the “stuff” in a 5061, it will change (rise) at least 10C
> > after turn on.
> >
> > Bob
> > ___
> > time-nuts mailing list -- time-nuts@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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Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Bob kb8tq]

Hi

Any real crystal you buy will have a tolerance on the angle. In the case of a 
crystal cut for turn
the temperature will be a bit different and you will match your oven to it. If 
you attempt a zero 
angle cut, you will never really hit it and there is no way to compensate for 
the problem. 

Bob

> On Jun 2, 2017, at 3:19 PM, Donald E. Pauly  wrote:
> 
> A cut at that angle has no turn over temperature. The zero temperature 
> coefficient point is 25°.  Its temperature coefficient everywhere else is 
> positive.
> 
> On Friday, June 2, 2017, Bob kb8tq mailto:kb...@n1k.org>> 
> wrote:
> Hi
> 
> If you are going to use an oven, it’s better to run it at the turn 
> temperature of
> the crystal. That would put you above 50C for an AT and a bit higher still 
> for an SC.
> 
> Bob
> 
> > On Jun 2, 2017, at 2:09 PM, Donald E. Pauly  > > wrote:
> >
> > https://www.febo.com/pipermail/time-nuts/2017-May/105566.html 
> > <https://www.febo.com/pipermail/time-nuts/2017-May/105566.html>
> >
> > If we build this circuit it would be a bench model not designed to be
> > inside a hot chassis.  It would be able to lock ± 5° C of 25° C.  My
> > idea of an oven is to keep the crystal and oscillator at 25° C ±0.001
> > °C with 60 second warm up/cool down time.
> >
> > πθ°μΩω±√·Γλ
> > WB0KVV
> >
> > -- Forwarded message --
> > From: Bob kb8tq >
> > Date: Fri, Jun 2, 2017 at 5:57 AM
> > Subject: Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies
> > To: Discussion of precise time and frequency measurement 
> > >
> >
> > Hi
> >
> > I would suggest you check a few real crystals over the 20 to 40C range ….
> > With all the “stuff” in a 5061, it will change (rise) at least 10C
> > after turn on.
> >
> > Bob
> > ___
> > time-nuts mailing list -- time-nuts@febo.com 
> > To unsubscribe, go to 
> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts 
> > <https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts>
> > and follow the instructions there.
> 

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Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Richard (Rick) Karlquist]

I said no *manufacturer* does it this way.  NBS is not
a manufacturer.  In a one-off money-is-no-object non-portable
standard, you can make direct multiplication work.  It
will not work well in a 5061, because of RF leakage
issues specific to the 5061 that are well documented.
Bolting on a different synthesizer does nothing to change that.

The decision not to use direct multiplication has nothing to
do with not being able to figure out how to synthesize the
correct frequency.  Certainly by the time we did the 5071A,
we were already using DDS, and it wouldn't have been any
problem to synthesize for direct multiplication if we had
wanted to do that.  You seem to be doing it the hard way
(pre DDS) involving Diophantine equations.  So it's easier
to do direct multiply than it used to be, but that doesn't
necessarily mean you should do it that way.

Rick

On 6/2/2017 10:59 AM, Donald E. Pauly wrote:

https://www.febo.com/pipermail/time-nuts/2017-May/105566.html

A guy by the name of David W. Allan used direct multiplication to
build NBS-4 and NBS-5, see http://tf.nist.gov/general/pdf/65.pdf .  He
didn't see anything wrong with it.  He used a commercial frequency
standard modified from 5 mc to 5.006880 mc.  That in turn was
multiplied by 1836.  This was a multiplier chain of 2·2·3·3·3·17.
When multiplied to 9192 mc, this is 90 cycles low so the standard
would be forced high by 0.05 cps..  They measured the locked frequency
standard to determine the actual frequency of the cesium line.  I
propose NO multiplier chain.

What are the supposed problems in using a direct submultiple of the
cesium resonance?  It seems to me that all other techniques result in
more phase noise there.  I found the relationship 91.92631770
mc·(137,075/126,008)=99,999,999.98992 cps=100,000.000--0.01008 cps.
It is low by 0.1 ppb and therefore cannot be adjusted by C field
current.  The C field can only lower the frequency.  There is another
relationship that gives a higher frequency of a fraction of a part per
billion which is easily adjustable.  Perhaps HP was unaware that such
a frequency exists.

πθ°μΩω±√·Γλ
WB0KV


-- Forwarded message --
From: Richard (Rick) Karlquist 
Date: Thu, Jun 1, 2017 at 10:01 PM
Subject: Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies
To: Discussion of precise time and frequency measurement
, "Donald E. Pauly" ,
"rwa...@aol.com" 


Direct multiplication to 9192 MHz isn't used
by any manufacturer of any atomic clock that I
know of, due to its well known disadvantages.
I can state for a fact that it was summarily
rejected by the designers of the 5060/5061
(Cutler, et al).  In the 5071, I (being the
RF designer) also summarily rejected it.
The architecture that is instead used is indeed
complex and expensive as you say.  It is
also ACCURATE.

Rick


On 6/1/2017 7:04 PM, Donald E. Pauly wrote:


https://www.febo.com/pipermail/time-nuts/2017-May/105566.html

The lock system on the HP5071 is complex and expensive.  My plan to
improve the HP5061B is to to use a pair of third overtone crystals
running at 91.9 mc and 100 mc.  I have come up with the magic numbers
to lock them together.  This eliminates all multipliers with the
exception of the A4 board. The 12.61 mc synthesizer input presently
wastes half the microwave power produced by the 90 mc input in the
unused lower sideband. Therefore only half the 91.9 mc drive is
required.

Eight bit ECL dividers in one package are available to perform the
necessary lock.  When multiplied by 100 to the cesium resonance line,
the 91.9 mc frequency is a few cycles high so that C field currents
are reasonable. With crystal cuts for zero temperature coefficient at
25°C, it is possible to get along without an oven.  Room temperature
performance at 25°C±5°C is ±15·10^-9.  Oscillator warm up time would
be measured in seconds.

Square wave modulation of variable frequency and amplitude shows
promise for reducing the noise effects of the beam tube.  You can
smoothly change the lock time constant, deviation and frequency.  This
would avoid the big disturbance of the HP5061B when you switch from
OPR to LTC. (OPR=operate with 1 second time constant, LTC=operate with
100 second time constant)

πθ°μΩω±√·Γλ
WB0KV
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Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Bob kb8tq]

Hi

If you are going to use an oven, it’s better to run it at the turn temperature 
of 
the crystal. That would put you above 50C for an AT and a bit higher still for 
an SC.

Bob

> On Jun 2, 2017, at 2:09 PM, Donald E. Pauly  wrote:
> 
> https://www.febo.com/pipermail/time-nuts/2017-May/105566.html
> 
> If we build this circuit it would be a bench model not designed to be
> inside a hot chassis.  It would be able to lock ± 5° C of 25° C.  My
> idea of an oven is to keep the crystal and oscillator at 25° C ±0.001
> °C with 60 second warm up/cool down time.
> 
> πθ°μΩω±√·Γλ
> WB0KVV
> 
> -- Forwarded message --
> From: Bob kb8tq 
> Date: Fri, Jun 2, 2017 at 5:57 AM
> Subject: Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies
> To: Discussion of precise time and frequency measurement 
> 
> Hi
> 
> I would suggest you check a few real crystals over the 20 to 40C range ….
> With all the “stuff” in a 5061, it will change (rise) at least 10C
> after turn on.
> 
> Bob
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[time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Donald E. Pauly]

https://www.febo.com/pipermail/time-nuts/2017-May/105566.html

A guy by the name of David W. Allan used direct multiplication to
build NBS-4 and NBS-5, see http://tf.nist.gov/general/pdf/65.pdf .  He
didn't see anything wrong with it.  He used a commercial frequency
standard modified from 5 mc to 5.006880 mc.  That in turn was
multiplied by 1836.  This was a multiplier chain of 2·2·3·3·3·17.
When multiplied to 9192 mc, this is 90 cycles low so the standard
would be forced high by 0.05 cps..  They measured the locked frequency
standard to determine the actual frequency of the cesium line.  I
propose NO multiplier chain.

What are the supposed problems in using a direct submultiple of the
cesium resonance?  It seems to me that all other techniques result in
more phase noise there.  I found the relationship 91.92631770
mc·(137,075/126,008)=99,999,999.98992 cps=100,000.000--0.01008 cps.
It is low by 0.1 ppb and therefore cannot be adjusted by C field
current.  The C field can only lower the frequency.  There is another
relationship that gives a higher frequency of a fraction of a part per
billion which is easily adjustable.  Perhaps HP was unaware that such
a frequency exists.

πθ°μΩω±√·Γλ
WB0KV


-- Forwarded message --
From: Richard (Rick) Karlquist 
Date: Thu, Jun 1, 2017 at 10:01 PM
Subject: Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies
To: Discussion of precise time and frequency measurement
, "Donald E. Pauly" ,
"rwa...@aol.com" 


Direct multiplication to 9192 MHz isn't used
by any manufacturer of any atomic clock that I
know of, due to its well known disadvantages.
I can state for a fact that it was summarily
rejected by the designers of the 5060/5061
(Cutler, et al).  In the 5071, I (being the
RF designer) also summarily rejected it.
The architecture that is instead used is indeed
complex and expensive as you say.  It is
also ACCURATE.

Rick


On 6/1/2017 7:04 PM, Donald E. Pauly wrote:
>
> https://www.febo.com/pipermail/time-nuts/2017-May/105566.html
>
> The lock system on the HP5071 is complex and expensive.  My plan to
> improve the HP5061B is to to use a pair of third overtone crystals
> running at 91.9 mc and 100 mc.  I have come up with the magic numbers
> to lock them together.  This eliminates all multipliers with the
> exception of the A4 board. The 12.61 mc synthesizer input presently
> wastes half the microwave power produced by the 90 mc input in the
> unused lower sideband. Therefore only half the 91.9 mc drive is
> required.
>
> Eight bit ECL dividers in one package are available to perform the
> necessary lock.  When multiplied by 100 to the cesium resonance line,
> the 91.9 mc frequency is a few cycles high so that C field currents
> are reasonable. With crystal cuts for zero temperature coefficient at
> 25°C, it is possible to get along without an oven.  Room temperature
> performance at 25°C±5°C is ±15·10^-9.  Oscillator warm up time would
> be measured in seconds.
>
> Square wave modulation of variable frequency and amplitude shows
> promise for reducing the noise effects of the beam tube.  You can
> smoothly change the lock time constant, deviation and frequency.  This
> would avoid the big disturbance of the HP5061B when you switch from
> OPR to LTC. (OPR=operate with 1 second time constant, LTC=operate with
> 100 second time constant)
>
> πθ°μΩω±√·Γλ
> WB0KV
> ___
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>
>
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Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Bob kb8tq]

Hi


> On Jun 1, 2017, at 10:04 PM, Donald E. Pauly  wrote:
> 
> https://www.febo.com/pipermail/time-nuts/2017-May/105566.html
> 
> The lock system on the HP5071 is complex and expensive.  My plan to
> improve the HP5061B is to to use a pair of third overtone crystals
> running at 91.9 mc and 100 mc.  I have come up with the magic numbers
> to lock them together.  This eliminates all multipliers with the
> exception of the A4 board. The 12.61 mc synthesizer input presently
> wastes half the microwave power produced by the 90 mc input in the
> unused lower sideband. Therefore only half the 91.9 mc drive is
> required.
> 
> Eight bit ECL dividers in one package are available to perform the
> necessary lock.  When multiplied by 100 to the cesium resonance line,
> the 91.9 mc frequency is a few cycles high so that C field currents
> are reasonable. With crystal cuts for zero temperature coefficient at
> 25°C, it is possible to get along without an oven.  Room temperature
> performance at 25°C±5°C is ±15·10^-9.  

I would suggest you check a few real crystals over the 20 to 40C range ….
With all the “stuff” in a 5061, it will change (rise) at least 10C after turn 
on. 

Bob


> Oscillator warm up time would
> be measured in seconds.
> 
> Square wave modulation of variable frequency and amplitude shows
> promise for reducing the noise effects of the beam tube.  You can
> smoothly change the lock time constant, deviation and frequency.  This
> would avoid the big disturbance of the HP5061B when you switch from
> OPR to LTC. (OPR=operate with 1 second time constant, LTC=operate with
> 100 second time constant)
> 
> πθ°μΩω±√·Γλ
> WB0KV
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Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Richard (Rick) Karlquist]

Direct multiplication to 9192 MHz isn't used
by any manufacturer of any atomic clock that I
know of, due to its well known disadvantages.
I can state for a fact that it was summarily
rejected by the designers of the 5060/5061
(Cutler, et al).  In the 5071, I (being the
RF designer) also summarily rejected it.
The architecture that is instead used is indeed
complex and expensive as you say.  It is
also ACCURATE.

Rick

On 6/1/2017 7:04 PM, Donald E. Pauly wrote:

https://www.febo.com/pipermail/time-nuts/2017-May/105566.html

The lock system on the HP5071 is complex and expensive.  My plan to
improve the HP5061B is to to use a pair of third overtone crystals
running at 91.9 mc and 100 mc.  I have come up with the magic numbers
to lock them together.  This eliminates all multipliers with the
exception of the A4 board. The 12.61 mc synthesizer input presently
wastes half the microwave power produced by the 90 mc input in the
unused lower sideband. Therefore only half the 91.9 mc drive is
required.

Eight bit ECL dividers in one package are available to perform the
necessary lock.  When multiplied by 100 to the cesium resonance line,
the 91.9 mc frequency is a few cycles high so that C field currents
are reasonable. With crystal cuts for zero temperature coefficient at
25°C, it is possible to get along without an oven.  Room temperature
performance at 25°C±5°C is ±15·10^-9.  Oscillator warm up time would
be measured in seconds.

Square wave modulation of variable frequency and amplitude shows
promise for reducing the noise effects of the beam tube.  You can
smoothly change the lock time constant, deviation and frequency.  This
would avoid the big disturbance of the HP5061B when you switch from
OPR to LTC. (OPR=operate with 1 second time constant, LTC=operate with
100 second time constant)

πθ°μΩω±√·Γλ
WB0KV
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[time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Donald E. Pauly]

https://www.febo.com/pipermail/time-nuts/2017-May/105566.html

The lock system on the HP5071 is complex and expensive.  My plan to
improve the HP5061B is to to use a pair of third overtone crystals
running at 91.9 mc and 100 mc.  I have come up with the magic numbers
to lock them together.  This eliminates all multipliers with the
exception of the A4 board. The 12.61 mc synthesizer input presently
wastes half the microwave power produced by the 90 mc input in the
unused lower sideband. Therefore only half the 91.9 mc drive is
required.

Eight bit ECL dividers in one package are available to perform the
necessary lock.  When multiplied by 100 to the cesium resonance line,
the 91.9 mc frequency is a few cycles high so that C field currents
are reasonable. With crystal cuts for zero temperature coefficient at
25°C, it is possible to get along without an oven.  Room temperature
performance at 25°C±5°C is ±15·10^-9.  Oscillator warm up time would
be measured in seconds.

Square wave modulation of variable frequency and amplitude shows
promise for reducing the noise effects of the beam tube.  You can
smoothly change the lock time constant, deviation and frequency.  This
would avoid the big disturbance of the HP5061B when you switch from
OPR to LTC. (OPR=operate with 1 second time constant, LTC=operate with
100 second time constant)

πθ°μΩω±√·Γλ
WB0KV
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[time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Donald E. Pauly]

https://www.febo.com/pipermail/time-nuts/2017-May/105554.html

Our attempt to measure the low frequency noise to determine the
possible lock improvement was a failure. We will have to get access to
the Loop Gain pot to get a flat signal at low impedance.  Beware of
low frequency roll off.

I found out that the feedback amplifier on the A7 board causes the
electron multiplier output to roll off above 19 cps.  It places an
8,200 pFd condenser across the 1 M load resistor which causes the roll
off.  Here is a linear sweep up to 8 kc.
http://gonascent.com/papers/hp/hp5061/waveform/wideswee.jpg  It shows
the 274 cps second harmonic as well as the 16 cps roll off.

Our previous posts involving various modulation schemes were correct
because we drove the scope directly from the electron multiplier.
While the meter driver is a convenient amplifier, you have to
disconnect C1 to prevent the low frequency roll off. The feedback
amplifier has a gain proportional to frequency.  This restores
flatness above 19 cps for the loop gain pot.  I got a gain of 141 at
137 cps with a lagging phase angle of 90°.  R10 is loaded by C1 which
drops the level at that frequency by 7:1.  Effective gain is about
20:1 on the Loop Gain pot in the hi gain position of S1.  Gain is
about 7 in the low gain position.  In both positions low frequency
roll off is about 19 cps.

πθ°μΩω±√·Γλ
WB0KV
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[time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[cdelect]

Donald,

Will look forward to seeing  your Allan Deviation plots before and after.
That will be the only way to verify your modification will make any
improvement.
I suspect the improvement at a few seconds will degrade it at other Tau.

Cheers,

Corby

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Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Bob kb8tq]

Hi

Having run a 5071A with a *very* good 10811 in it, the OCXO does dictate what 
happens at 0.1 seconds. 
Once you get past that, you are headed into a bit of a gray zone. You are 
partly looking at the Cs and partly
looking at the OCXO. Pushing out the crossover between the two could help you 
at 1 second. The gotcha is
that the “hump” will still be there, just a bit further out. The net effect at 
(say) 100 seconds could easily be worse
with the “fix”. 

Bob

> On May 27, 2017, at 8:15 PM, Richard (Rick) Karlquist  
> wrote:
> 
> On 5/27/2017 2:08 PM, Donald E. Pauly wrote:
> 
>> I am investigating the total redesign of the HP5061B lock system for
>> vastly improved performance.  It looks like the performance of the
>> HP5071A can be beaten by 10 to 1 for averaging times on the order of a
>> few seconds.
>> πθ°μΩω±√·Γλ
>> WB0KV
> 
> That's an interesting claim, but it could be valid.
> The 5071A flywheel is a 10811 selected for performance
> and modified to have additional electronic tuning
> range (I was involved in that) but otherwise it is
> plain vanilla 10811.  At a few seconds averaging time,
> this oscillator is basically open loop.  It might be
> possible to improve a 5071A by simply finding a 10811
> with exceptional short term stability.  The tail of
> the distribution curve went down at least an order of
> magnitude, according to Jack Kusters at HP.
> 
> In any event, you could use an unmodified 5071A or maybe
> a 5061B high performance option and discipline some
> really good XO.  Certainly, the 10811 isn't the world's best
> XO.  You'll need to prevent your XO from getting bothered
> by microphonics, stray magnetic fields, 2G turnover, temperature
> fluctuations, and humidity if not hermetic , etc.  The 5071A is
> impervious to all that as it is.
> 
> Is that what you had in mind?
> 
> I remember before I worked for HP visiting JPL's Goldstone
> tracking station.  They had a 5061A that disciplined a
> hydrogen maser for VLBI.  They said a plain 5061A was useless for their
> work.  OTOH, a hydrogen maser without drift correction was
> also useless for their work.  They had a huge room with 100's
> of racks of equipment, but the 5061A and H maser had their
> own dedicated room.
> 
> Rick Karlquist N6RK
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Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Richard (Rick) Karlquist]

Wow Tom, great posting.  All I can add is that in the 5061 there is
a tradeoff that the higher the C field is, the more sensitive it is
to errors.  That tempered the decision in the past.  With the 5071,
we have Zeeman line sampling so that the C field can be measured
by physics, not by precision magnetics.  IIRC, this allowed Len
Cutler to use a larger C field.  Separating the lines farther is
more important in the 5071A because the other error sources are
reduced.

Rick Karlquist

On 5/25/2017 9:23 PM, Tom Van Baak wrote:

Donald,

You're familiar with the 9,192,631,770 Hz definition of the SI second; but that's only 
for an "unperturbed" atom. The bad news is that in order to make the cesium 
beam operate at the central resonance peak one actually has to violate the SI definition 
and perturb it -- by applying a magnetic field (the so-called C-field), as well as other 
factors. This cannot be avoided. The good news is that the shift can be calculated.

In other words, because a magnetic field must be applied the actual cesium 
resonance frequency is not 9192.631770 MHz. The synthesizer locks to the peak, 
but the peak is at a slightly higher frequency than the nominal book value. 
This detailed note from hp may help:

http://leapsecond.com/museum/hp5062c/theory.htm

Different model beam tubes use different field strength / Zeeman frequency. 
Search the archives for lots of good postings about all these magic frequencies 
-- google: site:febo.com zeeman

If you want to see what the resonance peaks (all 7 of them) actually look after 
the C-field is applied see:

http://leapsecond.com/pages/cspeak/
and (poster size):
http://leapsecond.com/pages/cfield/

See also John's version:

http://www.ke5fx.com/cs.htm

One final comment -- the perturbed vs. unperturbed issue is far more complex 
than a single correction. To get an idea of the math and physics complexity of 
a laboratory Cs beam standard read some of these:

http://tf.nist.gov/general/pdf/1497.pdf
http://tf.nist.gov/general/pdf/65.pdf
http://tf.boulder.nist.gov/general/pdf/101.pdf

/tvb

- Original Message -
From: "Donald E. Pauly" 
To: "time-nuts" ; "Donald E. Pauly" 
Sent: Thursday, May 25, 2017 7:55 PM
Subject: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies


https://www.febo.com/pipermail/time-nuts/2017-May/105298.html

The synthesizer in the HP5061B generates a frequency of about
9,192,631,772.5 cps when the 5 mc oscillator is exactly on frequency.
First the 5 mc oscillator is multiplied by 18 to 90 mc on the A1
board.  That in turn is multiplied by 102 in the A4 board to give
9,180 mc.

The 5 mc is also divided by 4079 to produce 1,225.790635 cps.  That in
turn is multiplied by 10,305 to produce 12,631,772.5 cps.  This is
added to the 9180 mc in the A4 mixer to produce the final frequency of
9,192,631,772.5 cps approximately.  This is higher than the defined
frequency of 9,192,631,770 cps by about 2.5 cps or 271·10^-12.  If I
figured it right, the C field adjustment only has a range of
40·10^-12.  This seems to be insufficient to put the standard on
frequency.

Can anyone explain these mysteries?  Does anyone know why this
frequency was chosen?  Does anyone know the choice for the frequency
of the HP5071 cesium?

πθ°μΩω±√·Γλ
WB0KV
4,079=prime
10,305=5x9x229
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[time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[cdelect]

Donald,

HP changed from 12.631771.6 Mhz to 12.631772.5 Mhz in the later days.

The Zeeman frequency changed to correspond from 42.82Khz to 53.53Khz.

The 5071A uses a Zeeman frequency of 39.949Khz.

I believe they liked the stability a bit more at the different C-field
current.

Either way will put you correctly on frequency at the output (5 or 10Mhz)



See:

https://www.febo.com/pipermail/time-nuts/2005-April/018171.html

Read Toms reply and my post below his.

The 5071A synthesizer is always jumping around to control the C-field.

It's basic frequency is 131.8Khz

Basic info here.

http://leapsecond.com/corby/5071comb.pdf

Cheers,

Corby
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Re: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Tom Van Baak]

Donald,

You're familiar with the 9,192,631,770 Hz definition of the SI second; but 
that's only for an "unperturbed" atom. The bad news is that in order to make 
the cesium beam operate at the central resonance peak one actually has to 
violate the SI definition and perturb it -- by applying a magnetic field (the 
so-called C-field), as well as other factors. This cannot be avoided. The good 
news is that the shift can be calculated.

In other words, because a magnetic field must be applied the actual cesium 
resonance frequency is not 9192.631770 MHz. The synthesizer locks to the peak, 
but the peak is at a slightly higher frequency than the nominal book value. 
This detailed note from hp may help:

http://leapsecond.com/museum/hp5062c/theory.htm

Different model beam tubes use different field strength / Zeeman frequency. 
Search the archives for lots of good postings about all these magic frequencies 
-- google: site:febo.com zeeman

If you want to see what the resonance peaks (all 7 of them) actually look after 
the C-field is applied see:

http://leapsecond.com/pages/cspeak/
and (poster size):
http://leapsecond.com/pages/cfield/

See also John's version:

http://www.ke5fx.com/cs.htm

One final comment -- the perturbed vs. unperturbed issue is far more complex 
than a single correction. To get an idea of the math and physics complexity of 
a laboratory Cs beam standard read some of these:

http://tf.nist.gov/general/pdf/1497.pdf
http://tf.nist.gov/general/pdf/65.pdf
http://tf.boulder.nist.gov/general/pdf/101.pdf

/tvb

- Original Message - 
From: "Donald E. Pauly" 
To: "time-nuts" ; "Donald E. Pauly" 
Sent: Thursday, May 25, 2017 7:55 PM
Subject: [time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies


https://www.febo.com/pipermail/time-nuts/2017-May/105298.html

The synthesizer in the HP5061B generates a frequency of about
9,192,631,772.5 cps when the 5 mc oscillator is exactly on frequency.
First the 5 mc oscillator is multiplied by 18 to 90 mc on the A1
board.  That in turn is multiplied by 102 in the A4 board to give
9,180 mc.

The 5 mc is also divided by 4079 to produce 1,225.790635 cps.  That in
turn is multiplied by 10,305 to produce 12,631,772.5 cps.  This is
added to the 9180 mc in the A4 mixer to produce the final frequency of
9,192,631,772.5 cps approximately.  This is higher than the defined
frequency of 9,192,631,770 cps by about 2.5 cps or 271·10^-12.  If I
figured it right, the C field adjustment only has a range of
40·10^-12.  This seems to be insufficient to put the standard on
frequency.

Can anyone explain these mysteries?  Does anyone know why this
frequency was chosen?  Does anyone know the choice for the frequency
of the HP5071 cesium?

πθ°μΩω±√·Γλ
WB0KV
4,079=prime
10,305=5x9x229
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[time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

[Donald E. Pauly]

https://www.febo.com/pipermail/time-nuts/2017-May/105298.html

The synthesizer in the HP5061B generates a frequency of about
9,192,631,772.5 cps when the 5 mc oscillator is exactly on frequency.
First the 5 mc oscillator is multiplied by 18 to 90 mc on the A1
board.  That in turn is multiplied by 102 in the A4 board to give
9,180 mc.

The 5 mc is also divided by 4079 to produce 1,225.790635 cps.  That in
turn is multiplied by 10,305 to produce 12,631,772.5 cps.  This is
added to the 9180 mc in the A4 mixer to produce the final frequency of
9,192,631,772.5 cps approximately.  This is higher than the defined
frequency of 9,192,631,770 cps by about 2.5 cps or 271·10^-12.  If I
figured it right, the C field adjustment only has a range of
40·10^-12.  This seems to be insufficient to put the standard on
frequency.

Can anyone explain these mysteries?  Does anyone know why this
frequency was chosen?  Does anyone know the choice for the frequency
of the HP5071 cesium?

πθ°μΩω±√·Γλ
WB0KV
4,079=prime
10,305=5x9x229
___
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To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.