Re: [time-nuts] patents and hobbyist projects

[Brooke Clarke]

Hi Attila:

In the late 1950s I bought an oscilloscope kit branded EICO (Electronic Instrument Co).  The story was that if sold as a 
completed product would have violated a patent.


--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
The lesser of evils is still evil.

 Original Message 

On Fri, 13 May 2016 19:32:58 -0500
David  wrote:


Thanks for those.  I went over them pretty carefully and what I am
proposing is not covered by either although that would not protect me
from a debilitating patent lawsuit.

I wouldn't worry about patent lawsuits at all unless you intend to
start a multi-million business.

I've been active for over a decade in the extremely patent ridden
field of open source video coding (video encoders and players).
Everything in video coding is patented. For loops, 2D FFT/DCTs,
taking a difference of two values... you name it. Yet, over all
those years, there were very few clashes with companies on
intellectual property, and most of them boiled down on using
some of their trademarked names, more than anything else.

As a hobbyist, you are not a target. For one, patents are about
commercial use only. If you don't sell it, patents don't apply
(this is a bit simplified, but not incorrect). You cannot be
sued for publishing schematics or blueprints either. It's not
infringement to talk about a patent, is it? And last but not
least, you don't have money. Even if someone sued you, they
will not get anything out of it, so it's not worth the truble.

If a company feels like they need to do something, you most
likely will get an email telling you that they don't like
your blog post, or whatever, and that you should take it
offline. If comply, nothing will happen. If you answer back
that you are insisting on your right of free speech, it
is very likely that nothing will happen either. At most
you'll get another email saying that you should really consider it.


Attila Kinali




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Re: [time-nuts] Temperature controlled TCVCXO

[Bob Camp]

Hi

Indeed, you would probably do better with a simple XO than with a TCXO. A 
proper 
OCXO is temperature tested and the gain and set point of the oven are adjusted 
to 
optimize the temperature performance. 

Bob
> On May 14, 2016, at 5:52 PM, David  wrote:
> 
> As you pointed out earlier, with a TCXO, any inflection points of the
> crystal itself will be unavailable because the temperature coefficient
> at any one point will be the product of the crystal and the
> temperature compensation circuitry.
> 
> I am left to wonder if this will work better with a TCXO or just an
> XO.  The later would allow for a better optimized voltage control but
> at that point, I will have just reinvented the ovenized crystal
> oscillator using AT cut crystals and operating at room temperature.
> 
> Do OCXOs use internal temperature compensation other than that
> provided by the oven itself?
> 
>> Bottom line: A $10 eBay OCXO is likely to beat an ovenized or cooled TCXO. 
> 
> Designing something which relies on the availability of often
> questionable Ebay items just bugs me.
> 
> On Sat, 14 May 2016 08:54:36 -0400, you wrote:
> 
>> Hi
>> 
>> If the crystal has a “most stable point” it will be a point that the slope 
>> goes
>> from positive to negative (or vice versa). These points are symmetrical 
>> about 
>> the “center” of the crystal curve. For an AT cut, your center will be just a 
>> bit above
>> 25C. How far above depends on the geometry of the blank and a few other 
>> things.
>> For simplicity you see 25 used a lot.
>> 
>> If you look at the curves on the link posted earlier they follow a pattern. 
>> Anything 
>> below “zero angle” never goes through a slope change The zero angle goes flat
>> at the center. The “useful” part of the curves have a turn at 25 +/- X where 
>> X can 
>> be anything from 5 to 100C in normal crystal. 
>> 
>> You need to dig into the actual math to take a look at the slopes near turn. 
>> Obviously
>> the turn at 50C is a better bet for your OCXO than the one at 125C.
>> 
>> The enemy of any temperature stabilization system is waste heat. On an OCXO
>> with a normal heater, there is some (small) current in the circuit even when 
>> the heater
>> is turned off. With a TEC, there is a *lot* of waste heat when cooling. The 
>> systems
>> I have seen using them get into stacked devices and water cooling pretty 
>> quickly. 
>> 
>> Bob
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Re: [time-nuts] Temperature controlled TCVCXO

[David]

As you pointed out earlier, with a TCXO, any inflection points of the
crystal itself will be unavailable because the temperature coefficient
at any one point will be the product of the crystal and the
temperature compensation circuitry.

I am left to wonder if this will work better with a TCXO or just an
XO.  The later would allow for a better optimized voltage control but
at that point, I will have just reinvented the ovenized crystal
oscillator using AT cut crystals and operating at room temperature.

Do OCXOs use internal temperature compensation other than that
provided by the oven itself?

>Bottom line: A $10 eBay OCXO is likely to beat an ovenized or cooled TCXO. 

Designing something which relies on the availability of often
questionable Ebay items just bugs me.

On Sat, 14 May 2016 08:54:36 -0400, you wrote:

>Hi
>
>If the crystal has a “most stable point” it will be a point that the slope goes
>from positive to negative (or vice versa). These points are symmetrical about 
>the “center” of the crystal curve. For an AT cut, your center will be just a 
>bit above
>25C. How far above depends on the geometry of the blank and a few other things.
>For simplicity you see 25 used a lot.
>
>If you look at the curves on the link posted earlier they follow a pattern. 
>Anything 
>below “zero angle” never goes through a slope change The zero angle goes flat
>at the center. The “useful” part of the curves have a turn at 25 +/- X where X 
>can 
>be anything from 5 to 100C in normal crystal. 
>
>You need to dig into the actual math to take a look at the slopes near turn. 
>Obviously
>the turn at 50C is a better bet for your OCXO than the one at 125C.
>
>The enemy of any temperature stabilization system is waste heat. On an OCXO
>with a normal heater, there is some (small) current in the circuit even when 
>the heater
>is turned off. With a TEC, there is a *lot* of waste heat when cooling. The 
>systems
>I have seen using them get into stacked devices and water cooling pretty 
>quickly. 
>
>Bob
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Re: [time-nuts] Temperature controlled TCVCXO

[David]

It is only a 5 digit multimeter.  The specifications for the
temperature controlled reference and amplifiers are 10 times better
than the basic accuracy.

On Sat, 14 May 2016 10:26:42 -0500, you wrote:

>Note that the 3450B has an accuracy of 10E-5.
>
>You're probably looking for something a lot better than that.
>
>Bill Hawkins 
>
>>-Original Message-
>>From: David
>>Sent: Friday, May 13, 2016 8:28 PM
>
>>It figures that HP would have done this if anybody had.  I am not that
>>familiar with their design history so thanks for bringing this to my
>>attention.
>
>>I did not find anything in the theory section of the original service
>>manual although it does have the schematic but K04BB has a supplement
>>which discusses the 3450A peltier chamber and circuit in detail.  They
>>even sort of mention that the gain of the peltier differs significantly
>>between heating and cooling.
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Re: [time-nuts] Microchip PIC CTMU

[Attila Kinali]

On Sat, 14 May 2016 20:51:44 +0200
Herbert Poetzl  wrote:

> > The upgraded version III had IIRC a resolution of ~25ps with
> > better than 100ps achieved. Eventhough the PICTIC III design is
> > a bit more involved than then II, it's still relatively simple
> > (it uses more stable current sources, buffer opamps, external
> > ADCs and an active offset compensation scheme).
> 
> Hmm, sounds interesting ...
> Is there a PICTIC III schematic somewhere?

I don't have any. All I have is some description of the changes
Richard did to the PICTIC II in a couple of private mails.

Attila Kinali

-- 
Reading can seriously damage your ignorance.
-- unknown
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Re: [time-nuts] Microchip PIC CTMU

[Herbert Poetzl]

On Fri, May 13, 2016 at 07:51:07PM +0200, Attila Kinali wrote:
> On Fri, 13 May 2016 07:36:10 -0400
> Bob Camp  wrote:

>> Given that a “real” TDC is a resistor and capacitor
>> attached to a FPGA pin (plus the ADC) the cost of doing it
>> better is not all that much. You can get down to a few hundred
>> ps without a lot of crazy effort ( still using the MCU ADC).

> The PICTIC II did 250ps resolution with an effective resolution
> of 680ps[1].

> The upgraded version III had IIRC a resolution of ~25ps with
> better than 100ps achieved. Eventhough the PICTIC III design is
> a bit more involved than then II, it's still relatively simple
> (it uses more stable current sources, buffer opamps, external
> ADCs and an active offset compensation scheme).

Hmm, sounds interesting ...
Is there a PICTIC III schematic somewhere?

Thanks in advance,
Herbert

>   Attila Kinali

> PS: Does anyone know what happend to Richard McCorkle? I haven't heard
> of him in ages.

> [1] http://www.ke5fx.com/pictic.htm

> -- 
> Reading can seriously damage your ignorance.
>   -- unknown
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[time-nuts] HP5065A environmental sensitivities

[cdelect]

Luciano.

Hi,

1) it is difficult to read the frequency value on the plot. Can you
specify?

The plot is averaged to get the signal out of the noise, The P-P
calibration offset on the left allows you to estimate the deviation of
the other parts of the plot. The short term stability of the 5065A at 1
sec is causing the noise you see.

2) how do you set the offset of the op-amp trimmer ?

The trimmer is set for zero out of the op-amp at ambient pressure, this
allows the output to be plus/minus,
not critical just zero it after you install it.

3) do you think is possible to use the -20V on the HP5065A instead the
-12V from the DC-DC converter?

Probably would work fine as the load on the minus side is just the op
amp.

4) what frequency measurement system do you  use?

The maser is input to one side of a DMTD unit, the 5065A at about a .5Hz
offset via the  A1 synthesizer
is input to the common oscillator input of the DMTD. This setup give a
SMTD configuration.
A ping-pong counter then feeds a laptop.
A good quartz can be used instead of the Maser but WILL show up as drift
in the plot.

 
I am curious to know how you have generate the barometric swing.

Put the 5065A in a sealed box (easy to say hard to make work!), zero the
op-amp, run pressure up to .5PSI (-160mv at op-amp), then when done
reverse pump and pump down to -.5PSI (+160mv at op-amp). When done remove
pump and go back to ambient pressure. (I used a 12 Volt pump used to
inflate/deflate an inflatable bed, also used a variable supply into the
pump to allow setting the pressure/vacuum)
The box I made has a LARGE two sided heat sink on the lid, one heat sink
goes down into the box and the other is outside. This allowed me to keep
the 5065A at around 44 degrees C during the tests. (box stayed sealed for
a couple weeks while I generated data.) This box will also be used for
the temperature testing.

The SBT R7 resistor is used to set the P-P current change generated by
the +-160mv output to match the P-P frequency excursion caused by the
same. Being of opposite polarities they will then cancel out any
barometric changes.

Cheers,

Corby

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[time-nuts] MIT Flea & HP 5328

[bownes]

Apologies to those not in or around Boston tomorrow. You can ignore this msg. 

I'll be at the flea tomorrow selling off a 5328 with 10811 OXCO & 15GHz 
prescaler and a few other goodies.

I seem to recall that there are generally a few of us in attendance. Perhaps we 
could have an impromptu gathering of time nuts at say, 11 AM? 

Bob
KI2L
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[time-nuts] patents and hobbyist projects (was: Temperature controlled TCVCXO)

[Attila Kinali]

On Fri, 13 May 2016 19:32:58 -0500
David  wrote:

> Thanks for those.  I went over them pretty carefully and what I am
> proposing is not covered by either although that would not protect me
> from a debilitating patent lawsuit.

I wouldn't worry about patent lawsuits at all unless you intend to
start a multi-million business.

I've been active for over a decade in the extremely patent ridden
field of open source video coding (video encoders and players).
Everything in video coding is patented. For loops, 2D FFT/DCTs,
taking a difference of two values... you name it. Yet, over all
those years, there were very few clashes with companies on
intellectual property, and most of them boiled down on using
some of their trademarked names, more than anything else.

As a hobbyist, you are not a target. For one, patents are about
commercial use only. If you don't sell it, patents don't apply
(this is a bit simplified, but not incorrect). You cannot be
sued for publishing schematics or blueprints either. It's not
infringement to talk about a patent, is it? And last but not
least, you don't have money. Even if someone sued you, they
will not get anything out of it, so it's not worth the truble.

If a company feels like they need to do something, you most
likely will get an email telling you that they don't like
your blog post, or whatever, and that you should take it
offline. If comply, nothing will happen. If you answer back
that you are insisting on your right of free speech, it 
is very likely that nothing will happen either. At most
you'll get another email saying that you should really consider it.


Attila Kinali


-- 
Reading can seriously damage your ignorance.
-- unknown
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Re: [time-nuts] Temperature controlled TCVCXO

[Bill Hawkins]

Note that the 3450B has an accuracy of 10E-5.

You're probably looking for something a lot better than that.

Bill Hawkins 

-Original Message-
From: David
Sent: Friday, May 13, 2016 8:28 PM

On Fri, 13 May 2016 11:38:06 -0500, you wrote:

>David wrote:
>> I was thinking of holding the temperature right at 25C or maybe a 
>> little higher at an inflection point to minimize the possibility of 
>> condensation.  The difficulty is that the ambient temperature could 
>> vary above or below that so the TEC has to both heat and cool but 
>> that is a solved problem.
>
>The HP 3450A & B model digital multimeters used a Peltier device to 
>control the temperature of the voltage reference zener diode.  You can 
>download the manual for the "B" model from Keysight's web site to get 
>an idea of the control circuitry 
>(http://www.keysight.com/main/techSupport.jspx?searchT=3450B=3450B:e
psg:pro=3450B:epsg:pro=US=eng).
>There's also a sales bulletin for that model that gives a bit more 
>information about the Peltier device and chamber 
>(http://www.ko4bb.com/getsimple/index.php?id=manuals). Search for 3450A

>on that site.
>
>The chamber is controlled to 43C by the Peltier device, allowing quite 
>fast warmup times for the instrument, and operation above normal 
>environmental temperatures.
>
>Cheers,
>Dave M

It figures that HP would have done this if anybody had.  I am not that
familiar with their design history so thanks for bringing this to my
attention.

I did not find anything in the theory section of the original service
manual although it does have the schematic but K04BB has a supplement
which discusses the 3450A peltier chamber and circuit in detail.  They
even sort of mention that the gain of the peltier differs significantly
between heating and cooling.


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Re: [time-nuts] Temperature controlled TCVCXO

[Bob Camp]

Hi

If the crystal has a “most stable point” it will be a point that the slope goes
from positive to negative (or vice versa). These points are symmetrical about 
the “center” of the crystal curve. For an AT cut, your center will be just a 
bit above
25C. How far above depends on the geometry of the blank and a few other things.
For simplicity you see 25 used a lot.

If you look at the curves on the link posted earlier they follow a pattern. 
Anything 
below “zero angle” never goes through a slope change The zero angle goes flat
at the center. The “useful” part of the curves have a turn at 25 +/- X where X 
can 
be anything from 5 to 100C in normal crystal. 

You need to dig into the actual math to take a look at the slopes near turn. 
Obviously
the turn at 50C is a better bet for your OCXO than the one at 125C.

The enemy of any temperature stabilization system is waste heat. On an OCXO
with a normal heater, there is some (small) current in the circuit even when 
the heater
is turned off. With a TEC, there is a *lot* of waste heat when cooling. The 
systems
I have seen using them get into stacked devices and water cooling pretty 
quickly. 

Bob

> On May 13, 2016, at 11:26 PM, David  wrote:
> 
> Just to be clear here, my original question referred to using a TEC to
> maintain a constant temperature where the TCVCXO with the crystal has
> the best stability.  I assume this would be around 25C but testing
> might reveal that it is actually more stable at a point slightly
> higher or lower.
> 
> So the TCXO would be operating at or around a fixed point near 25C
> whether the ambient temperature is higher or lower.  Bidirectional
> control of the TEC with a servo amplifier is not difficult and that
> second HP link is pretty close to what I had in mind.
> 
> On Fri, 13 May 2016 16:30:20 -0700, you wrote:
> 
>> Hi Nathan,
>> 
>> Let me state what Bob is driving at in a different way.
>> 
>> Your biggest problem with a TCXO is the crystal.  It is cut so that the 
>> slope, relative to temperature, has the shallowest curve around room 
>> temperature (between 20 to 25 degrees C).  If you cool or heat it from 
>> that range the slope becomes more radical.  The more radical the slope 
>> the greater the change in frequency for a given change in temperature.  
>> The exact opposite of what is trying to be achieved.
>> 
>> This translates into having to have an extremely tightly controlled oven 
>> system in an attempt to overcome the radical slope.  In addition you 
>> will also have to consider the elevated temperature effects on the other 
>> components.  It is a never ending battle.
>> 
>> BillWB6BNQ
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Re: [time-nuts] Temperature controlled TCVCXO

[David]

Just to be clear here, my original question referred to using a TEC to
maintain a constant temperature where the TCVCXO with the crystal has
the best stability.  I assume this would be around 25C but testing
might reveal that it is actually more stable at a point slightly
higher or lower.

So the TCXO would be operating at or around a fixed point near 25C
whether the ambient temperature is higher or lower.  Bidirectional
control of the TEC with a servo amplifier is not difficult and that
second HP link is pretty close to what I had in mind.

On Fri, 13 May 2016 16:30:20 -0700, you wrote:

>Hi Nathan,
>
>Let me state what Bob is driving at in a different way.
>
>Your biggest problem with a TCXO is the crystal.  It is cut so that the 
>slope, relative to temperature, has the shallowest curve around room 
>temperature (between 20 to 25 degrees C).  If you cool or heat it from 
>that range the slope becomes more radical.  The more radical the slope 
>the greater the change in frequency for a given change in temperature.  
>The exact opposite of what is trying to be achieved.
>
>This translates into having to have an extremely tightly controlled oven 
>system in an attempt to overcome the radical slope.  In addition you 
>will also have to consider the elevated temperature effects on the other 
>components.  It is a never ending battle.
>
>BillWB6BNQ
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Re: [time-nuts] HP5065A environmental sensitivities

[timeok]

Hi Corby,

very interesting. I have some questions?

1) it is difficult to read the frequency value on the plot. Can you specify?
2) how do you set the offset of the op-amp trimmer ?
3) do you think is possible to use the -20V on the HP5065A instead the -12V 
from the DC-DC converter?
4) what frequency measurement system do yo have used for?

I am curious to know how you have generate the barometric swing.


thanks ,
Luciano
www.timeok.it


On Fri 13/05/16 03:29 ,  wrote:

> HP 5065A Environmental sensitivity
> 
> First here is a comparison between the specified sensitivities of various
> 
> Rubidium units.
> 
> Barometric per mbar Temperature per degree C
> 
> HP 5065A 6.3X10-14 1.6X10-12
> M100 FRK 8.7x10-14 2.4X10-12
> LPRO 1.0X10-13 6.0X10-12
> FE5650A unspecified 1.1X10-11
> FRSC 1.0X10-13 1.1X10-11
> PRS10 unspecified 1.0X10-11
> 
> As you can see the HP specs are better than the others!
> 
> After much effort I managed to measure the actual sensitivity of a 5065A
> on my bench.
> It was much better than the spec at 1.55X10-14/mbar! I then installed
> a barometric compensation circuit consisting of a sensor and OP amp. This
> feeds the C-field circuit in the 5065A.
> After alignment the sensitivity was so low that it was below my
> measurement noise floor!
> 
> Attached is a frequency plot that illustrates the correction. On the left
> is a calibration offset from the Maser of plus/minus 1.84X10-12. The
> middle section shows the frequency with the compensation on during
> several cycles of plus/minus 35 mbar. The right is with compensation off
> and the plus/minus 35mbar excursions.
> 
> Also attached is a schematic of the compensation circuitry.
> 
> Now I'll work on the temperature sensitivity. Poul-Henning has explored
> in this area and has some good information to start with.
> 
> Cheers,
> 
> Corby
> 
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