Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

[Logan Cummings]

Hi Folks,

   This discussion of temperature measurement with ADCs has crossed into my
professional life and without being too much of a commercial plug just
wanted to mention that I support Linear Technology's temp-to-bits family of
ICs: LTC2983, LTC2984, LTC2986.

   Overview: each part has 3 24-bit delta-sigma ADCs along with low leakage
input buffers, excitation sources, an internal mux, and a small
linearization engine. They can measure just about any type of temperature
sensor and digitize it to deg C or F with really good accuracy. Ultimately
accuracy will depend on the sensor, your implementation, environmental
conditions, etc. but the parts have a lot of features that help you get the
most out of a given sensor.

   They aren't super cheap (Digi-Key pricing is particularly bad, if you
can order from Linear direct it's much better) but they are to my knowledge
by far the simplest way to interface to a thermistor, RTD, thermocouple,
etc. and get <1degC accuracy.

Ping me off-list if you want to know more or have an application question
in mind.

-Logan
http://www.linear.com/product/LTC2983

On Wed, Jun 7, 2017 at 8:04 PM, jimlux  wrote:

> On 6/7/17 7:35 PM, Bob kb8tq wrote:
>
>> Hi
>>
>> Metal actually makes things a bit worse since it has a lower thermal
>> resistance than glass.
>> This is also why a high performance dewar is made from glass rather than
>> metal.  Yes, you
>> can go to weird stuff like titanium (it has been done). You can’t afford
>> that ….
>>
>> If you fill the entire dewar with a heat conductor you make things worse
>> still. The idea is to
>> *block* heat flow out of the heated area. Even without fill,  the wall of
>> the dewar goes from the outside
>> world to the heart of the heated area. It is the perfect “sneak" path
>> into the oven. Actually
>> it’s not that much of a sneak path since it’s a well known effect :)
>>
>> Again, none of this is particularly original. Take a hammer to any dewar
>> based OCXO and
>> the details are going to be similar.
>>
>>
> And the wires provide a thermal path - you've got to get power to it and
> the oscillator signal out.
>
> In dewar OCXOs (like the USOs made by APL), the leads are essentially the
> only thermal path in/out.
>
>
> BTW, you don't want to do oil filled. All oil filled electronics (unless
> welded closed) inevitably leaks, oozes, or otherwise puts oil on the
> outside. If you *must* have oil, then use solid, uninsulated wires to
> penetrate the surface of the oil. Otherwise you'll gain new appreciation
> for what capillary action is.
>
>
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/m
> ailman/listinfo/time-nuts
> and follow the instructions there.
>
___
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.

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

[jimlux]

On 6/7/17 7:35 PM, Bob kb8tq wrote:

Hi

Metal actually makes things a bit worse since it has a lower thermal resistance 
than glass.
This is also why a high performance dewar is made from glass rather than metal. 
 Yes, you
can go to weird stuff like titanium (it has been done). You can’t afford that ….

If you fill the entire dewar with a heat conductor you make things worse still. 
The idea is to
*block* heat flow out of the heated area. Even without fill,  the wall of the 
dewar goes from the outside
world to the heart of the heated area. It is the perfect “sneak" path into the 
oven. Actually
it’s not that much of a sneak path since it’s a well known effect :)

Again, none of this is particularly original. Take a hammer to any dewar based 
OCXO and
the details are going to be similar.



And the wires provide a thermal path - you've got to get power to it and 
the oscillator signal out.


In dewar OCXOs (like the USOs made by APL), the leads are essentially 
the only thermal path in/out.



BTW, you don't want to do oil filled. All oil filled electronics (unless 
welded closed) inevitably leaks, oozes, or otherwise puts oil on the 
outside. If you *must* have oil, then use solid, uninsulated wires to 
penetrate the surface of the oil. Otherwise you'll gain new appreciation 
for what capillary action is.


___
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.

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

[Bob kb8tq]

Hi

Metal actually makes things a bit worse since it has a lower thermal resistance 
than glass. 
This is also why a high performance dewar is made from glass rather than metal. 
 Yes, you
can go to weird stuff like titanium (it has been done). You can’t afford that ….

If you fill the entire dewar with a heat conductor you make things worse still. 
The idea is to
*block* heat flow out of the heated area. Even without fill,  the wall of the 
dewar goes from the outside 
world to the heart of the heated area. It is the perfect “sneak" path into the 
oven. Actually
it’s not that much of a sneak path since it’s a well known effect :) 

Again, none of this is particularly original. Take a hammer to any dewar based 
OCXO and
the details are going to be similar. 

Bob 
 
> On Jun 7, 2017, at 9:51 PM, Chris Albertson  wrote:
> 
> On Wed, Jun 7, 2017 at 3:18 PM, Bob kb8tq  wrote:
> 
>> Hi
>> 
>> Consider that a lot of the heat flow is through the glass wall of the
>> vacuum gizmo. You want to tie your heater(s) to it in order to create
>> an iso-thermal “wall”. Often this is done by gluing the whole assembly
>> together.
>> 
> 
> Not glass walls.  Stainless steel.  The metal wall make it uniform.
> 
> I occurred to be that you could fill the container with a liquid.
> Something that has good thermal conductivity and it would be very uniform
> inside.   I don't know what, transformer oil perhaps?
> 
> -- 
> 
> Chris Albertson
> Redondo Beach, California
> ___
> 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.

___
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.

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

[Will Kimber]

For under $20 you can get a OCXO with Si5351A multi output oscillator
chip from QRP-Labs.


http://www.qrp-labs.com/ocxokit.html


No idea just how good it is but this link gives insight into how it was
developed.  Designed for WSPR radio transmissions.  GPS discipline can
be added.


http://www.hanssummers.com/ocxosynth


Cheers,

Will


On 06/08/2017 06:10 AM, Chris Albertson wrote:


> IT turrets out that you see MUCH more interesting designs when you lower
> the budget.  Anyone can make a high performance system even enough money.
> They waste half the cost on useless stuff and the product costs double what
> it should and is over complex but is works real, really well.   That's
> easy.  Harder and more interesting is "Can you make something just as good
> at 1/2 the price?"   Answer is usually Yes.  Then you say "what much do you
> loose if I set the price to 1/4?   The answer is surprisingly little if you
> get smart about sourcing parts.  Turns out about $180 is the minimum
> for pretty decent quality HiFi vacuum tube.
>
> An interesting graph would be Oven Specification vs. Price.  What is the
> minimum cost for keeping temperature to within 1.0 C, for 0.1C, 0.01 C?
>  Can you do 1.0C for under $5?   or 0.1C for under $10.I bet yes.
>
> I did an exercise a while back to see what is the minimum price and
> complexity to build a GPSDO that was good enough only to drive the lab
> bench instruments I have.   I implements only 1/2 od Lars W's design and
> cut his lines of code by about 90%.  Turns outhe cost is the XO and about
> $10.   Compared to my Thunderbolt, performance was not nearly as good but
> the ratio of performance over parts cost might be better.
>
>
>

___
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.

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

[Bob kb8tq]

Hi

Consider that a lot of the heat flow is through the glass wall of the 
vacuum gizmo. You want to tie your heater(s) to it in order to create
an iso-thermal “wall”. Often this is done by gluing the whole assembly
together. 

In addition, you probably also want a foam plug in the end
of the beast to keep from creating an even more non-uniform (= very
directional)  heat flow. Yes, the directivity issue is inherent in the design
approach. It’s not clear that you want to exaggerate it ….

Bob

> On Jun 7, 2017, at 6:03 PM, Attila Kinali  wrote:
> 
> On Wed, 7 Jun 2017 22:20:50 +0100
> Peter Vince  wrote:
> 
>>> Additionally: if I would set out to build my own OCXO today, I would
>>> go and buy one of those lunch thermos flasks to house everything. Their
>>> isolation is higher than anything you can easily build yourself,
>>> especially at that size. I would place the (inner) oven at the bottom,
>>> probably using a puck design similar to the E1938, place the electronics
>>> on top of it and close the lid using an aluminium plate which forms
>>> the outer oven.
>> 
>> Might there be a problem that a thermos flask is TOO well insulated, and
>> even the minimal heat generated in the electronics would be more than could
>> escape through the vacuum, and so the unit would cook?
> 
> That's why the top of the flask is closed with an aluminium plate.
> Assuming the plate on the top is around 5x5cm, that should give a
> thermal resistance in the order of 20-40°C/W. That's not low, but
> should be enough to support 100-400mW of heat generated inside
> with a moderate temperature differential. If it turns out not to
> be enough, making the plate bigger and attaching a few fins, or
> having a small fan blowing lightly on it should solve the problem.
> 
> 
>   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
> ___
> 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.

___
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.

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

[Attila Kinali]

On Wed, 7 Jun 2017 22:20:50 +0100
Peter Vince  wrote:

> > Additionally: if I would set out to build my own OCXO today, I would
> > go and buy one of those lunch thermos flasks to house everything. Their
> > isolation is higher than anything you can easily build yourself,
> > especially at that size. I would place the (inner) oven at the bottom,
> > probably using a puck design similar to the E1938, place the electronics
> > on top of it and close the lid using an aluminium plate which forms
> > the outer oven.
> 
> Might there be a problem that a thermos flask is TOO well insulated, and
> even the minimal heat generated in the electronics would be more than could
> escape through the vacuum, and so the unit would cook?

That's why the top of the flask is closed with an aluminium plate.
Assuming the plate on the top is around 5x5cm, that should give a
thermal resistance in the order of 20-40°C/W. That's not low, but
should be enough to support 100-400mW of heat generated inside
with a moderate temperature differential. If it turns out not to
be enough, making the plate bigger and attaching a few fins, or
having a small fan blowing lightly on it should solve the problem.


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
___
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.

Re: [time-nuts] Poor man's oven

[Bob kb8tq]

Hi

Keep in mind that on a per cubic inch basis, copper is right up there
for creating a thermal mass ….

Bob
> On Jun 7, 2017, at 5:51 PM, Attila Kinali  wrote:
> 
> Hoi Rick,
> 
> On Wed, 7 Jun 2017 14:21:52 -0700
> "Richard (Rick) Karlquist"  wrote:
> 
> 
>> Actually, the oven mass of the E1938A is much heavier than the
>> 10811 and is made of copper to boot.
> [...]
>> The crystal case is well connected to the oven mass and gets
>> heated by conduction.  I don't think radiation is a player.
> 
> Hmm.. seems like I have misunderstood the design.
> I think I should aquire one of the non-working E1938 and
> pry the can open. 
> 
> Does anyone have a E1938 that's not working anymore
> and would be willing to offer it to science? :-)
> 
> 
>   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
> ___
> 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.

___
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.

Re: [time-nuts] Poor man's oven

[Attila Kinali]

Hoi Rick,

On Wed, 7 Jun 2017 14:21:52 -0700
"Richard (Rick) Karlquist"  wrote:


> Actually, the oven mass of the E1938A is much heavier than the
> 10811 and is made of copper to boot.
[...]
> The crystal case is well connected to the oven mass and gets
> heated by conduction.  I don't think radiation is a player.

Hmm.. seems like I have misunderstood the design.
I think I should aquire one of the non-working E1938 and
pry the can open. 

Does anyone have a E1938 that's not working anymore
and would be willing to offer it to science? :-)


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
___
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.

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

[Charles Steinmetz]

Chris wrote:


Assume me goal is to regulate temperer of an aluminum block to within
0.1C, how good must my ADC be?   Is an effective 6-bits good enough?

 *   *   *If I scale the input to the ADC such that it os 1.0C from 0 to 63
counts then each cunt is 1/64 C which is about 6 times better then my
allowed error of 0.6 C.


The required number of bits depends on the range it represents -- it is 
all about scale, as your second paragraph above seems to recognize.


You are right, 6 bits is enough to represent a 1C span to the nearest 
1/64C.  But that is not the whole answer.  This representation will be 
mapped to 64 steps of oven output.  If the oven has very little power, 
these can be reasonably fine steps -- but recovery from large errors 
will be painfully slow.  On the other hand, if the oven has normal-ish 
power, the steps will be much too large to control the oven temperature 
finely.


You need both sufficient range and sufficient resolution to accomplish 
the task at hand.  In reality, 6 bits will be *both* too coarse for fine 
control and will also have insufficient range.  Experience has shown 
that 12 bits (actual, not nominal) is barely to not really enough to do 
the job with real crystal ovens if you want fine temperature control 
over a useful range of temperatures.


Consider digital audio. 6 bits is plenty to digitize audio to the 
nearest 30uV (typical LSB value for CD-quality audio) -- BUT, only over 
a 1.9mV range.  Actual CD-quality audio requires one to maintain this 
same resolution over a range of 2V, which requires 16 bits.


Best regards,

Charles


___
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.

Re: [time-nuts] Poor man's oven

[Bob kb8tq]

Hi

The crystal enclosure may (or may not … who knows ..) be back filled with a low 
level
of helium. It does not take much of a backfill for conduction inside the 
crystal holder to
dominate the heat transfer vs radiation transfer.

Bob

> On Jun 7, 2017, at 5:21 PM, Richard (Rick) Karlquist  
> wrote:
> 
> 
> 
> On 6/7/2017 1:09 PM, Attila Kinali wrote:
>> 
>> makes the PI loop better behaved. Also the thermal mass of the
>> crystal holder is quite small. Especially compared ot the 10811.
> 
> Actually, the oven mass of the E1938A is much heavier than the
> 10811 and is made of copper to boot.
>> Due to the flat puck design, I assume that the majority of the
>> heat going to the crystal holder is due to radiation (unless I
>> missed some insulation around the crystal). Radiation, albeit being
>> a high "resistivity" transport mechanism, has very low inherent
>> "capacitance". And thus the delay associated with this transport
>> mechanism is low.
> 
> The crystal case is well connected to the oven mass and gets
> heated by conduction.  I don't think radiation is a player.
> 
>> There are probably a lot more small design decisions in the E1938
>> that make it such a superb oven. More than I probably will ever
>> be able to figure out. And, I still am astonished how well it works.
>>  Attila Kinalid
> 
> Rick N6RK
> ___
> 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.

___
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.

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

[Bob kb8tq]

Hi


> On Jun 7, 2017, at 4:40 PM, Attila Kinali  wrote:
> 
> On Wed, 7 Jun 2017 15:25:38 -0400
> Charles Steinmetz  wrote:
> 
>> Chris wrote:
>> 
>>> Assume me goal is to regulate temperer of an aluminum block to within
>>> 0.1C, how good must my ADC be?   Is an effective 6-bits good enough?
>>> 
>>> *   *   *If I scale the input to the ADC such that it os 1.0C from 0 to 
>>> 63
>>> counts then each cunt is 1/64 C which is about 6 times better then my
>>> allowed error of 0.6 C.
>> 
>> The required number of bits depends on the range it represents -- it is 
>> all about scale, as your second paragraph above seems to recognize.
>> 
>> You are right, 6 bits is enough to represent a 1C span to the nearest 
>> 1/64C.  But that is not the whole answer.  This representation will be 
>> mapped to 64 steps of oven output.  If the oven has very little power, 
>> these can be reasonably fine steps -- but recovery from large errors 
>> will be painfully slow.  On the other hand, if the oven has normal-ish 
>> power, the steps will be much too large to control the oven temperature 
>> finely.
> 
> Addedum to what Charles wrote:
> If you want to build a temperature control for something similar
> like an quartz oven, just get one of the modern delta-sigma ADCs.
> You'll pay €10 for one, but it's really a hassle free way to
> precisely measure temperature. As most of these have a large
> number of channels, you can measure multiple sensors as well
> at no additional cost (beside the thermistor).
> 
> Additionally: if I would set out to build my own OCXO today, I would
> go and buy one of those lunch thermos flasks to house everything. Their
> isolation is higher than anything you can easily build yourself,
> especially at that size. I would place the (inner) oven at the bottom,
> probably using a puck design similar to the E1938, place the electronics
> on top of it and close the lid using an aluminium plate which forms
> the outer oven. 
> 
> Such a design allows to have low temperature gradients within the flask
> (due to the metal walls). The outer oven allows to optimize the inner
> oven for stability without the need to deal with large temperature ranges.
> And all together it is still quite cheap.

I certainly do not disagree with the idea of using a thermos or a cheap eBay
dewar in a home brew OCXO project. 

It’s not all a free lunch. You still have issues. One somewhat counter 
intuitive one
is the gradient / cooling issue. The same super duper insulation that helps
you also hurts you. Your internal circuitry will have a finite power 
requirement.
Yes it can be pretty low, but it’s still there. You have very high thermal 
resistance.
Even small power sources will generate noticeable temperature rise(s).

No that observation is not original to me. It’s been passed down over the 
generations of OCXO designers. I’d love to identify just who passed it on.
Unfortunately it’s been way to long for me to remember exactly who.

Bob


> 
> One drawback, though, is the large size of the flask. But for a hobby
> project that does not need to fit into another product, this is fine.
> 
> 
>   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
> ___
> 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.

___
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.

Re: [time-nuts] Poor man's oven

[Richard (Rick) Karlquist]

On 6/7/2017 1:09 PM, Attila Kinali wrote:


makes the PI loop better behaved. Also the thermal mass of the
crystal holder is quite small. Especially compared ot the 10811.


Actually, the oven mass of the E1938A is much heavier than the
10811 and is made of copper to boot.


Due to the flat puck design, I assume that the majority of the
heat going to the crystal holder is due to radiation (unless I
missed some insulation around the crystal). Radiation, albeit being
a high "resistivity" transport mechanism, has very low inherent
"capacitance". And thus the delay associated with this transport
mechanism is low.


The crystal case is well connected to the oven mass and gets
heated by conduction.  I don't think radiation is a player.


There are probably a lot more small design decisions in the E1938
that make it such a superb oven. More than I probably will ever
be able to figure out. And, I still am astonished how well it works.

Attila Kinalid


Rick N6RK
___
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.

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

[Peter Vince]

On 7 June 2017 at 21:40, Attila Kinali  wrote:
>
> Additionally: if I would set out to build my own OCXO today, I would
> go and buy one of those lunch thermos flasks to house everything. Their
> isolation is higher than anything you can easily build yourself,
> especially at that size. I would place the (inner) oven at the bottom,
> probably using a puck design similar to the E1938, place the electronics
> on top of it and close the lid using an aluminium plate which forms
> the outer oven.

Might there be a problem that a thermos flask is TOO well insulated, and
even the minimal heat generated in the electronics would be more than could
escape through the vacuum, and so the unit would cook?
___
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.

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

[Attila Kinali]

On Wed, 7 Jun 2017 15:25:38 -0400
Charles Steinmetz  wrote:

> Chris wrote:
> 
> > Assume me goal is to regulate temperer of an aluminum block to within
> > 0.1C, how good must my ADC be?   Is an effective 6-bits good enough?
> >
> >  *   *   *If I scale the input to the ADC such that it os 1.0C from 0 
> > to 63
> > counts then each cunt is 1/64 C which is about 6 times better then my
> > allowed error of 0.6 C.
> 
> The required number of bits depends on the range it represents -- it is 
> all about scale, as your second paragraph above seems to recognize.
> 
> You are right, 6 bits is enough to represent a 1C span to the nearest 
> 1/64C.  But that is not the whole answer.  This representation will be 
> mapped to 64 steps of oven output.  If the oven has very little power, 
> these can be reasonably fine steps -- but recovery from large errors 
> will be painfully slow.  On the other hand, if the oven has normal-ish 
> power, the steps will be much too large to control the oven temperature 
> finely.

Addedum to what Charles wrote:
If you want to build a temperature control for something similar
like an quartz oven, just get one of the modern delta-sigma ADCs.
You'll pay €10 for one, but it's really a hassle free way to
precisely measure temperature. As most of these have a large
number of channels, you can measure multiple sensors as well
at no additional cost (beside the thermistor).

Additionally: if I would set out to build my own OCXO today, I would
go and buy one of those lunch thermos flasks to house everything. Their
isolation is higher than anything you can easily build yourself,
especially at that size. I would place the (inner) oven at the bottom,
probably using a puck design similar to the E1938, place the electronics
on top of it and close the lid using an aluminium plate which forms
the outer oven. 

Such a design allows to have low temperature gradients within the flask
(due to the metal walls). The outer oven allows to optimize the inner
oven for stability without the need to deal with large temperature ranges.
And all together it is still quite cheap.

One drawback, though, is the large size of the flask. But for a hobby
project that does not need to fit into another product, this is fine.


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
___
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.

Re: [time-nuts] Poor man's oven

[Attila Kinali]

On Tue, 6 Jun 2017 19:07:29 -0700
"Richard (Rick) Karlquist"  wrote:

> In the E1938A oscillator, we used a PIDI^2 loop.  IOW, a PID
> plus a double integrator.  This was Len Cutler's idea.
> Once the constants were dialed in, this worked phenomenally
> well in terms of transient response.  Even dumping in liquid
> nitrogen full throttle into the environmental test chamber
> barely wiggled the crystal temperature/frequency.

The E1938 is kind of special in several ways, IMHO.
Beside having a nice zero-gradient design (I really love
this idea :-) it has also a quite large surface vs volume.
This means that there is a lot of heat flow out of the
can and at the same time the (face) heater is large, which
makes the PI loop better behaved. Also the thermal mass of the
crystal holder is quite small. Especially compared ot the 10811.

Due to the flat puck design, I assume that the majority of the
heat going to the crystal holder is due to radiation (unless I
missed some insulation around the crystal). Radiation, albeit being
a high "resistivity" transport mechanism, has very low inherent
"capacitance". And thus the delay associated with this transport
mechanism is low.

There are probably a lot more small design decisions in the E1938
that make it such a superb oven. More than I probably will ever
be able to figure out. And, I still am astonished how well it works.

Attila Kinalid
-- 
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
___
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.

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

[Attila Kinali]

On Tue, 6 Jun 2017 16:43:30 -0700
Chris Albertson  wrote:

> > . Heck, the STM32F4xx have so much internal noise that the ENOB
> > of their ADC is below 6bit... so low that they even had to write an
> > appnote on how to do averaging to get back to the 12 bits the ADC is
> > spec'ed for. (but don't mention that to an ST sales person, they will
> > hate your guts afterwards).
> >
> 
> Can you actually get back all of those bits? 

No

>  How many samples would you need?

White Gaussian noise goes down with the square root of the number of samples.
1/f^a noise does not average out the same way.

> My current use case for the STM32 ADC is to track battery voltage
> and maybe 6 bits is enough but if I can get to 12 with a software-only fix
> I'll take it.  Batteries volts charge slowly so I'd have time to take many
> samples.   It's a rather mundane application.  Controlling a battery
> powered motor and I can't let theLiPo battery dichange below a limit so I'm
> sampling voltage at 1Hz.   Got a link to or the name of the app note?

Keep in mind that you will need a good voltage reference as well
to reach anything close to 12bit. Your LDO is _not_ a good voltage
reference (depending on type and load/source conditions they vary
eaily by 1-2%... not to talk about their noise)


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
___
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.

[time-nuts] HP 8640 Brass replacement gears

[Paul K.]

I can provide brass gears for your HP 8640 Signal generator.

If any members of the list are interested, please contact me off list.

wa0...@arrl.net

I will be happy to provide the information.

73

Paul K.

WA0BAG

--
Paul K. WA0BAG
___
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.

Re: [time-nuts] HP8640

[KA2WEU--- via time-nuts]

Yes I need one for 1 day, not to keep
 
 
In a message dated 6/7/2017 3:19:37 P.M. Eastern Daylight Time,  
scmcgr...@gmail.com writes:

Ulrich

I have an operational 8640 

Content by  Scott
Typos by Siri

> On Jun 7, 2017, at 11:35 AM, Dave Daniel   wrote:
> 
> There is, or was, a member of  the Yahoo hp_agilent forum who was making 
metal replacement gears for the  HP8640. I believe several members replaced 
the plastic gears with the new  metal ones and were able to bring their 
instruments back to life.
>  
> DaveD
> 
>> On 6/7/2017 8:56 AM, Bert Kehren via  time-nuts wrote:
>> I think it will be difficult to find a well  working 8640, plastic gears
>> will have by now totally  disintegrated. What part of it do you need, I 
may
>> have   something left.
>> Bert Kehren
>>In a message  dated 6/6/2017 9:06:05 P.M. Eastern Daylight Time,
>>  time-nuts@febo.com writes:
>> 
>> Hi , I  am trying to  find an well working  HP 8640 to do some   
measurements
>>  like SSB  FM and AM noise.
>>  
>> Who can help ?  73 de Ulrich  N1UL
>>  ___
>> 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.
>> 
>>  ___
>> 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.
> 
> 
> ---
> This email has  been checked for viruses by Avast antivirus software.
>  https://www.avast.com/antivirus
> 
>  ___
> 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.
___
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.

___
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.

Re: [time-nuts] HP8640

[Scott McGrath]

Ulrich

I have an operational 8640 

Content by Scott
Typos by Siri

> On Jun 7, 2017, at 11:35 AM, Dave Daniel  wrote:
> 
> There is, or was, a member of the Yahoo hp_agilent forum who was making metal 
> replacement gears for the HP8640. I believe several members replaced the 
> plastic gears with the new metal ones and were able to bring their 
> instruments back to life.
> 
> DaveD
> 
>> On 6/7/2017 8:56 AM, Bert Kehren via time-nuts wrote:
>> I think it will be difficult to find a well working 8640, plastic gears
>> will have by now totally disintegrated. What part of it do you need, I may
>> have  something left.
>> Bert Kehren
>>In a message dated 6/6/2017 9:06:05 P.M. Eastern Daylight Time,
>> time-nuts@febo.com writes:
>> 
>> Hi , I  am trying to find an well working  HP 8640 to do some  measurements
>>  like SSB  FM and AM noise.
>> 
>> Who can help ?  73 de Ulrich  N1UL
>> ___
>> 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.
>> 
>> ___
>> 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.
> 
> 
> ---
> This email has been checked for viruses by Avast antivirus software.
> https://www.avast.com/antivirus
> 
> ___
> 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.
___
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.

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

[Hal Murray]

albertson.ch...@gmail.com said:
> Assume me goal is to regulate temperer of an aluminum block to within 0.1C,
> how good must my ADC be?   Is an effective 6-bits good enough? 

I don't think you are asking the right question.

You can build a control loop with a 1 bit ADC.  Think of your typical 
household thermostat.

I'm not sure what the right question is.  I expect it will involve the 
sampling rate, the response time of the system, and the nature of the heater.

You also have to consider stability.


-- 
These are my opinions.  I hate spam.



___
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.

Re: [time-nuts] HP8640

[David Smith]

Hello Ulrich,

I have an 8640 I was going to put up for sale in the next few weeks. It’s in 
almost perfect condition. All of the gears are intact with no cracks or 
splitting. I think this SG may have been in a lab environment most of it’s 
lifetime.

Contact me off list if you are interested.

Dave W6TE
w...@msn.com

Sent from Mail for Windows 10

From: KA2WEU--- via time-nuts
Sent: Tuesday, June 6, 2017 6:06 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] HP8640

Hi , I am trying to find an well working  HP 8640 to do some  measurements
like SSB  FM and AM noise.

Who can help ?  73 de Ulrich N1UL
___
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.

___
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.

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

[Didier Juges]

The good news is that for oven control, you can typically filter the heck
out of the data and the noise may actually help you with dithering if it's
fairly random, so you should be able to get close to the specs. The main
thing you need is stability, linearity should not be a factor. One
limitation will be the built in reference so unless you can switch to an
external reference, that may be the main issue.

I have been using the Silabs line of 8051 uCs and I found their ADCs
handily meeting their specs, at least on the devices I have tried (I have
used up to 12 bit ADC on their parts).

I also have used the MSC1210 (from originally Burr Brown, now TI). The only
board that came close to the 24 bit advertised performance of their ADC was
the demo board from Burr Brown themselves, and it was very slow. Anything
that I designed with it (with their help and advice) never got anywhere
near that and I gave up on that chip.

Didier KO4BB

On Jun 6, 2017 4:17 PM, "Attila Kinali"  wrote:

On Tue, 6 Jun 2017 16:37:27 -0400
Bob kb8tq  wrote:

> Often when you dig into the details of MCU ADC’s they have a little note
“optimized for audio” or
> “not recommended for control loops”. It can be a bit of a head scratcher
to work out what they are
> getting at. The big issues in this case seem to be DC leakage and 1/F
noise. Yes, they do sort of go hand in hand :)
> You need to be willing to check out the ENOB at DC in order to use them
effectively in a simple
> OCXO setup. That or be willing to flip the bridge ends on demand and try
to cancel out the issues.
> Unfortunately that adds both complexity and a string of other fun and
games.

uC ADCs are only good for low resolution, slow signals. For anything else
you need an external ADC. Even if your uC datasheet claims that you have
a 12bit ADC, the reality is quite different. For one, these ADCs are not
well specified, the surounding digital logic has a profound effect that
changes dramatically depending on what other periphery you use or not.

You can always just subtract two bits of the ADCs resolution and you
wouldn't be wrong. Losing 3 bits to internal noise isn't unehard of
either. Heck, the STM32F4xx have so much internal noise that the ENOB
of their ADC is below 6bit... so low that they even had to write an
appnote on how to do averaging to get back to the 12 bits the ADC is
spec'ed for. (but don't mention that to an ST sales person, they will
hate your guts afterwards).

Rule of thumb: If you need your ADC DC stable, more than 8bit resolution,
or more than 10-1000 samples per second: use an external ADC.

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
___
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.
___
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.

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

[Bob kb8tq]

Hi

There is a gotcha with the initial assumption: You want the loop to be
*quiet* at a level well below 0.1C. If it is bouncing around that much,
the second order (rate defendant) tempco of a normal crystal will
become a pretty major issue. 

Simple rule of thumb - add at least two bits past whatever the target is. 
More or less, if you *are* after 0.1C and that comes out to 6 bits, you need
eight solid bits to get things to work properly. 

Bob

> On Jun 7, 2017, at 2:10 PM, Chris Albertson  wrote:
> 
> One question for the control theory experts.
> 
> Assume me goal is to regulate temperer of an aluminum block to within 0.1C,
> how good must my ADC be?   Is an effective 6-bits good enough?
> 
> It seems to me the problem with fewer bits is only quantization noise.
> Lets assume 6-bits.  This is 1 part in 64.   If I scale the input to the
> ADC such that it os 1.0C from 0 to 63 counts then each cunt is 1/64 C
> which is about 6 times better then my allowed error of 0.6 C.
> 
> My gut-feel is that this is marginal but could work ("work" is defined as
> holds temperature within the range) but I'd be happier using 8 bits.  Im
> pretty sure I can get 8-bits by over sampling and filtering.
> 
> I don't know how to analyze this but I'm guessing with n-bits each each
> sample has a 1/2 bit error so my I and D terms in the PID controller will
> accumulate lots of 1/2 bit errors.   I thing I want them "a couple orders
> of magnitude" smaller then the  allied temperature range.
> 
> Of cose one could buy the best ADC on the market.   But this is POOR MAN's
> project.   So he asks, "What is the lowers performance/cost part that will
> allow the system to meet its specification?
> 
> BTW, a related story.I'm on another couple lists that deal with vacuum
> tube audio.  We see the same things there people correctlypointing out how
> to make something better but the question is always how much better and at
> what cost an does it matter.   So a fun project was proposed.  Set a budget
> of $200 to build a tube based stereo Hi Fi amplifier.  Who can do the
> best.  Youhade to publish the BOM with prices and suppliers.   Extra points
> if you came in under budget. This eliminated all the suggestions to buy
> high end hand made transformers from Sweden.
> 
> IT turrets out that you see MUCH more interesting designs when you lower
> the budget.  Anyone can make a high performance system even enough money.
> They waste half the cost on useless stuff and the product costs double what
> it should and is over complex but is works real, really well.   That's
> easy.  Harder and more interesting is "Can you make something just as good
> at 1/2 the price?"   Answer is usually Yes.  Then you say "what much do you
> loose if I set the price to 1/4?   The answer is surprisingly little if you
> get smart about sourcing parts.  Turns out about $180 is the minimum
> for pretty decent quality HiFi vacuum tube.
> 
> An interesting graph would be Oven Specification vs. Price.  What is the
> minimum cost for keeping temperature to within 1.0 C, for 0.1C, 0.01 C?
> Can you do 1.0C for under $5?   or 0.1C for under $10.I bet yes.
> 
> I did an exercise a while back to see what is the minimum price and
> complexity to build a GPSDO that was good enough only to drive the lab
> bench instruments I have.   I implements only 1/2 od Lars W's design and
> cut his lines of code by about 90%.  Turns outhe cost is the XO and about
> $10.   Compared to my Thunderbolt, performance was not nearly as good but
> the ratio of performance over parts cost might be better.
> 
> 
> 
> On Tue, Jun 6, 2017 at 2:39 PM, Mark Sims  wrote:
> 
>> Another thing to watch out for on processor ADCs is their performance near
>> the supply rails...  the AVR ADCs are particularly entertaining below
>> around 300 mV (with a 5V Vref).
>> ___
>> 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.
>> 
> 
> 
> 
> -- 
> 
> Chris Albertson
> Redondo Beach, California
> ___
> 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.

___
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.

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

[Chris Albertson]

One question for the control theory experts.

Assume me goal is to regulate temperer of an aluminum block to within 0.1C,
how good must my ADC be?   Is an effective 6-bits good enough?

It seems to me the problem with fewer bits is only quantization noise.
Lets assume 6-bits.  This is 1 part in 64.   If I scale the input to the
ADC such that it os 1.0C from 0 to 63 counts then each cunt is 1/64 C
 which is about 6 times better then my allowed error of 0.6 C.

My gut-feel is that this is marginal but could work ("work" is defined as
holds temperature within the range) but I'd be happier using 8 bits.  Im
pretty sure I can get 8-bits by over sampling and filtering.

I don't know how to analyze this but I'm guessing with n-bits each each
sample has a 1/2 bit error so my I and D terms in the PID controller will
accumulate lots of 1/2 bit errors.   I thing I want them "a couple orders
of magnitude" smaller then the  allied temperature range.

Of cose one could buy the best ADC on the market.   But this is POOR MAN's
project.   So he asks, "What is the lowers performance/cost part that will
allow the system to meet its specification?

BTW, a related story.I'm on another couple lists that deal with vacuum
tube audio.  We see the same things there people correctlypointing out how
to make something better but the question is always how much better and at
what cost an does it matter.   So a fun project was proposed.  Set a budget
of $200 to build a tube based stereo Hi Fi amplifier.  Who can do the
best.  Youhade to publish the BOM with prices and suppliers.   Extra points
if you came in under budget. This eliminated all the suggestions to buy
high end hand made transformers from Sweden.

IT turrets out that you see MUCH more interesting designs when you lower
the budget.  Anyone can make a high performance system even enough money.
They waste half the cost on useless stuff and the product costs double what
it should and is over complex but is works real, really well.   That's
easy.  Harder and more interesting is "Can you make something just as good
at 1/2 the price?"   Answer is usually Yes.  Then you say "what much do you
loose if I set the price to 1/4?   The answer is surprisingly little if you
get smart about sourcing parts.  Turns out about $180 is the minimum
for pretty decent quality HiFi vacuum tube.

An interesting graph would be Oven Specification vs. Price.  What is the
minimum cost for keeping temperature to within 1.0 C, for 0.1C, 0.01 C?
 Can you do 1.0C for under $5?   or 0.1C for under $10.I bet yes.

I did an exercise a while back to see what is the minimum price and
complexity to build a GPSDO that was good enough only to drive the lab
bench instruments I have.   I implements only 1/2 od Lars W's design and
cut his lines of code by about 90%.  Turns outhe cost is the XO and about
$10.   Compared to my Thunderbolt, performance was not nearly as good but
the ratio of performance over parts cost might be better.



On Tue, Jun 6, 2017 at 2:39 PM, Mark Sims  wrote:

> Another thing to watch out for on processor ADCs is their performance near
> the supply rails...  the AVR ADCs are particularly entertaining below
> around 300 mV (with a 5V Vref).
> ___
> 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.
>



-- 

Chris Albertson
Redondo Beach, California
___
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.

Re: [time-nuts] Relationship of frequency to stability

[John Franke]

There is no direct relationship between frequency and stability. For any given 
frequency, the stability is determined to a large extent by the technology used 
for the oscillator. For instance, at 1 kHz, a quartz crystal is normally more 
stable than a tuning fork which is normally better than a LC circuit which is 
normally better than a RC circuit. And even amongst a set of oscillators the 
stability is determined by the stability of the individual components, the 
design of the oscillator, and environment factors. There have been pendulum and 
tuning fork clocks better than some quartz crystal clocks. Quartz crystal 
clocks eventually became more stable than free pendulum clocks which were 
limited by gravitational variations. Some quartz oscillators are better than 
ammonia atomic clocks. I have tuning forks at 1 kHz that are more stable than 
some crystal oscillators and microwave klystrons. Stability is more related to 
the quality of the parts, the design of the oscillators the base tech
 nology and the control of environmental factors than to the frequency. 
Examples can be found where an oscillator based on older technology outperforms 
a newer potentially more stable technology through attention to detail in the 
construction and operation. 

Hope this helps!

John  WA4WDL
> On June 7, 2017 at 10:25 AM John Sloan  wrote:
> 
> 
> 
> SHORT VERSION: I’ve been trying to figure out what the relationship is 
> between frequency and stability - if there is one - that is, why oscillators 
> with higher frequencies tend to be more stable.
> 
> LONG VERSION: I got into this by building a home-brew NTP server using a 
> cesium-disciplined oscillator, specifically a Jackson Labs GPS-disciplined 
> oscillator board that incorporates a Microsemi Chip Scale Atomic Clock. I 
> started thinking about the 9,192,631,770Hz oscillator in the CSAC, the quartz 
> oscillator in my $10 Casio wristwatch that is perhaps 32768 Hz, the 8 Hz 
> balance wheel in my Rolex GMT Master II, the 6 Hz balance wheel in my 
> Hamilton Jazzmaster, and the maybe 5 Hz of some of my less expensive 
> mechanical wristwatches. In my personal experience, there is a correlation. I 
> kinda figure this has to do somehow with the Q calculation, but it’s just not 
> happening for me, math-wise. For example, arguments about relative error seem 
> to cancel out because of the greater number of ticks per second. I’m putting 
> a talk together and would like to rationalize this somehow. Googling hasn’t 
> provided any insights so far. Links to references would be great. Thanks for 
> any pointers!
> 
> --
> J. L. SloanDigital Aggregates Corp.
> +1 303 940 9064 (O)3440 Youngfield St. #209
> +1 303 489 5178 (M)Wheat Ridge CO 80033 USA
> jsl...@diag.comhttp://www.diag.com 
> ___
> 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.
___
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.

Re: [time-nuts] PPS sync

[Jerry Hancock]

That makes complete sense, it’s not disciplining anything, just pumping out the 
PPS and reporting the variance.  I don’t know why I didn’t think of it.

It’s interesting how it jumps around from PPS to PPS. 

Thank you,

Jerry


> On Jun 7, 2017, at 2:57 AM, Hal Murray  wrote:
> 
> 
> je...@hanler.com said:
>> Chris, I think you are onto something.  Running Lady Heather on this unit I
>> see a line under “receiver” with the term “SawT” and a parameter of 24ns.
>> So if we combine this information with what you teach below, it’s starting
>> to look like maybe the M12 unit is doing something different than the
>> Lucent.
> 
> The M12 is a timing receiver.  The Lucent is a GPSDO.
> 
> The Lucent will adjust the osc so it runs at 10 MHz and the phase is such 
> that the PPS lines up with UTC.
> 
> The M12 tells you the offset rather then adjusting the osc so the offset is 0.
> 
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
> ___
> 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.

___
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.

Re: [time-nuts] HP8640

[Dave Daniel]

There is, or was, a member of the Yahoo hp_agilent forum who was making 
metal replacement gears for the HP8640. I believe several members 
replaced the plastic gears with the new metal ones and were able to 
bring their instruments back to life.


DaveD

On 6/7/2017 8:56 AM, Bert Kehren via time-nuts wrote:

I think it will be difficult to find a well working 8640, plastic gears
will have by now totally disintegrated. What part of it do you need, I may
have  something left.
Bert Kehren
  
  
In a message dated 6/6/2017 9:06:05 P.M. Eastern Daylight Time,

time-nuts@febo.com writes:

Hi , I  am trying to find an well working  HP 8640 to do some  measurements
  
like SSB  FM and AM noise.


Who can help ?  73 de Ulrich  N1UL
___
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.

___
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.



---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

___
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.

Re: [time-nuts] Relationship of frequency to stability

[Bob kb8tq]

Hi

For something like a crystal oscillator, there is a relation between frequency 
and resonator Q. That
gives you a loose correlation between stability and oscillator frequency. 
Beyond that, there are 
substantial differences between the technologies you are comparing. That is the 
main source of
the differences you observe. You could extend the sequence to include trapped 
optical ion clocks
and continue the series …

Bob

> On Jun 7, 2017, at 10:25 AM, John Sloan  wrote:
> 
> 
> SHORT VERSION: I’ve been trying to figure out what the relationship is 
> between frequency and stability - if there is one - that is, why oscillators 
> with higher frequencies tend to be more stable.
> 
> LONG VERSION: I got into this by building a home-brew NTP server using a 
> cesium-disciplined oscillator, specifically a Jackson Labs GPS-disciplined 
> oscillator board that incorporates a Microsemi Chip Scale Atomic Clock. I 
> started thinking about the 9,192,631,770Hz oscillator in the CSAC, the quartz 
> oscillator in my $10 Casio wristwatch that is perhaps 32768 Hz, the 8 Hz 
> balance wheel in my Rolex GMT Master II, the 6 Hz balance wheel in my 
> Hamilton Jazzmaster, and the maybe 5 Hz of some of my less expensive 
> mechanical wristwatches. In my personal experience, there is a correlation. I 
> kinda figure this has to do somehow with the Q calculation, but it’s just not 
> happening for me, math-wise. For example, arguments about relative error seem 
> to cancel out because of the greater number of ticks per second. I’m putting 
> a talk together and would like to rationalize this somehow. Googling hasn’t 
> provided any insights so far. Links to references would be great. Thanks for 
> any pointers!
> 
> --
> J. L. SloanDigital Aggregates Corp.
> +1 303 940 9064 (O)3440 Youngfield St. #209
> +1 303 489 5178 (M)Wheat Ridge CO 80033 USA
> jsl...@diag.comhttp://www.diag.com 
> ___
> 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.

___
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.

Re: [time-nuts] HP8640

[Bert Kehren via time-nuts]

I think it will be difficult to find a well working 8640, plastic gears  
will have by now totally disintegrated. What part of it do you need, I may 
have  something left.
Bert Kehren
 
 
In a message dated 6/6/2017 9:06:05 P.M. Eastern Daylight Time,  
time-nuts@febo.com writes:

Hi , I  am trying to find an well working  HP 8640 to do some  measurements 
 
like SSB  FM and AM noise.

Who can help ?  73 de Ulrich  N1UL 
___
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.

___
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.

[time-nuts] Relationship of frequency to stability

[John Sloan]

SHORT VERSION: I’ve been trying to figure out what the relationship is between 
frequency and stability - if there is one - that is, why oscillators with 
higher frequencies tend to be more stable.

LONG VERSION: I got into this by building a home-brew NTP server using a 
cesium-disciplined oscillator, specifically a Jackson Labs GPS-disciplined 
oscillator board that incorporates a Microsemi Chip Scale Atomic Clock. I 
started thinking about the 9,192,631,770Hz oscillator in the CSAC, the quartz 
oscillator in my $10 Casio wristwatch that is perhaps 32768 Hz, the 8 Hz 
balance wheel in my Rolex GMT Master II, the 6 Hz balance wheel in my Hamilton 
Jazzmaster, and the maybe 5 Hz of some of my less expensive mechanical 
wristwatches. In my personal experience, there is a correlation. I kinda figure 
this has to do somehow with the Q calculation, but it’s just not happening for 
me, math-wise. For example, arguments about relative error seem to cancel out 
because of the greater number of ticks per second. I’m putting a talk together 
and would like to rationalize this somehow. Googling hasn’t provided any 
insights so far. Links to references would be great. Thanks for any pointers!

--
J. L. SloanDigital Aggregates Corp.
+1 303 940 9064 (O)3440 Youngfield St. #209
+1 303 489 5178 (M)Wheat Ridge CO 80033 USA
jsl...@diag.comhttp://www.diag.com 
___
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.

Re: [time-nuts] MCXO and dual mode

[Bob kb8tq]

Hi

Yes, you run both modes at the same time. You wire up two oscillator circuits 
to the
same crystal. One runs at the fundamental and the other runs at the third 
overtone. 
The two have a different temperature coefficient. (yes, that’s a bit weird, but 
it is true). 
The “offset” between the two modes lets you read out the temperature. 

If you build it properly, each oscillator will have a spur at the “other” 
frequency. That may or may not be an issue. If you use the fundamental output,
the third looks a lot like a third harmonic (but not quite ….).  Using the 
third 
overtone is a bit more problematic since the harmonic of the fundamental 
will create a close in spur. 

Bob

> On Jun 7, 2017, at 1:04 AM, Hal Murray  wrote:
> 
> 
> kb...@n1k.org said:
>> Let’s say both modes are running into a 32 pf load and it is a single
>> capacitor.  
> 
> I'm missing the big picture.
> 
> Can I run both modes at the same time?  Or do I switch between them?
> 
>> The beat frequency shifts since the two modes do not tune identically. 
> 
> That sounds like they are running at the same time.
> 
> What does the output look like?  I'd expect beats so the signal would drop 
> out for many cycles if I looked at the right place in time.  Is that sort of 
> signal good for anything other than being a thermometer?
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
> ___
> 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.

___
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.

Re: [time-nuts] TruePosition on the Arduino

[Hal Murray]

Argh/sorry.  I fatfingered something.  Wrong list.


-- 
These are my opinions.  I hate spam.



___
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.

Re: [time-nuts] TruePosition on the Arduino

[Hal Murray]

sobo...@sippysoft.com said:
> SO_BINTIME was ENOTSUPP with IPv6 from the day one.

Thanks.  Is that a literal ENOTSUPP?  Should I get an error from setsockopt?  
Or is that just shorthand for not-implemented?

Do you want a bug report?  If nothing else, the man page should be updated.

Just curious...  Why wasn't SO_BINTIME implemented for IPv6?  Since it works 
for IPv4 and SO_TIMESTAMP works for IPv4 and IPv6 I'd expect it would be easy 
to implement.

-- 
These are my opinions.  I hate spam.



___
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.

Re: [time-nuts] PPS sync

[Hal Murray]

je...@hanler.com said:
> Chris, I think you are onto something.  Running Lady Heather on this unit I
> see a line under “receiver” with the term “SawT” and a parameter of 
> 24ns.
> So if we combine this information with what you teach below, it’s starting
> to look like maybe the M12 unit is doing something different than the
> Lucent.

The M12 is a timing receiver.  The Lucent is a GPSDO.

The Lucent will adjust the osc so it runs at 10 MHz and the phase is such 
that the PPS lines up with UTC.

The M12 tells you the offset rather then adjusting the osc so the offset is 0.



-- 
These are my opinions.  I hate spam.



___
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.

[time-nuts] uC ADC resolution (was: Poor man's oven)

[Mark Sims]

Another thing to watch out for on processor ADCs is their performance near the 
supply rails...  the AVR ADCs are particularly entertaining below around 300 mV 
(with a 5V Vref).
___
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.

[time-nuts] TruePosition on the Arduino

[Mark Sims]

If you run it on a system with an accurately set clock,  Lady Heather can 
measure the offset (and standard deviation and ADEVs)  between the time in the 
receiver time code message and when the last byte of the time code message 
comes in.   It also calculates a histogram of the message offsets.   Since 
Heather does not use a 1PPS interrupt, it uses the message offset to adjust the 
receiver time code time to the displayed time (the on-screen clocks are updated 
when the last byte of the time code message comes in).

Most receivers are surprisingly well behaved in their message timing... a few 
are not.  Only a few receivers (like the Z38xx and RFTG-m) output the time code 
message before the 1PPS.  Most receivers have a message offset of around +200 
milliseconds.  The Jupiter receiver time codes are off by around 1200 
milliseconds!

I just added some code to Heather for doing an audible "tick" clock that ticks 
the second and beeps the minute (you can change that with your own sound 
files).  The tick clock uses the end-of-message offset time to make sure the 
ticks are closely aligned to the PPS time.

---

>  Calibrating your GPS pulse ambiguity is one of the all time great reasons to 
> get a
WWVB based wall clock !!!
___
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.