Re: [time-nuts] J06 HP-59992A time interval calibrator for HP-531xx counters

[Hal Murray]

> I hope the XOR doubler works well.

I think the initial comment about using a XOR mentioned a couple of gates for 
delay.

A trick from the old FPGA days.  You can guarantee that the pulse is wide 
enough to clock a FF if you put a FF in the chain.  That is replace the 
gates-for-delay with a FF.  Use the pulse to clock the FF and feed the output 
of the FF to the other side of the XOR.  (You may need some delay on the 
input to the FF to meet setup time.  You have the XOR delay to start with.)


-- 
These are my opinions.  I hate spam.



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[time-nuts] J06 HP-59992A time interval calibrator for HP-531xx counters

[Mark Sims]

I think it will take some testing to see if using an analog frequency doubler 
or XOR digital doubler will provide the best performance.   My gut says the 
analog doubler ($6) will work better than the ($0.20) XOR doubler.  I hope the 
XOR doubler works well.

It would be even better if the doubler / divider is not needed and one can just 
square the input 10 MHz.   The HP cal procedure says to feed a signal generator 
with a 10 MHz 50% duty cycle square wave to the counter.   Most signal 
generators don't tend to be all that precise about how well they do the 50% 
thing and HP does not specify a tolerance on the freq or duty cycle (or even 
which signal generator to use).  If the counter's internal cal routines do 
things right, it should be able to null out the asymmetries.
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Re: [time-nuts] Tuning a Symmetricom 1111C

[Tom Knox]

Hi Ed;

Thanks for the response. Great logic/detail on potential issues and solutions. 
The power supply issue seems completely intermittent and when running may be 
completely fine. That said I am leaning toward the power supply being the 
issue, it would explain all the issues. I first saw the power supply issue with 
the batteries installed, I removed the fuse and the missing voltages came up 
and the unit locked. before with those voltages absent it was displaying the 
lock light every few seconds after warmup. I had assumed a bad battery had 
created too great a load on the supply. But it failed to come up again when I 
rebooted and then came up again the next time I rebooted. It is either zero or 
correct. I have several problematic 4065's and thought they had 1000B's, I will 
check if any have a C. It would be easy to swap them and would resolve the 
question of if these problems are related. The unit I have may actually be 
locking but outside it's acceptable EFC range. Phase Noise is except
 ional about -120dB @ 1Hz offset 5MHz.

I will look at solder on the bricks, for the symptoms that could be the issue.

Thanks again for your help;

Thomas Knox




From: time-nuts  on behalf of Ed Palmer 

Sent: Saturday, July 8, 2017 12:03 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] Tuning a Symmetricom C

Hi Tom,

I have a Datum 4065A standard with a Datum B oscillator.  I've never
had to tune it, but it appears to be a clone of the HP 10811 so you
might get some insights by researching that oscillator. However, if
you're having issues with the +-15V supplies, I'd STRONGLY suggest that
you resolve those before attempting to retune the oscillator.

Circuit information for these units isn't available, but reading between
the lines, I note the following:
- My unit uses an AD9713BAP D/A converter to drive the EFC.  It requires
+-5V supplies.
- The system monitors +5V, +15V, and -15V, but not -5V so where is -5V
coming from?  I see an LM320-5V on the mainboard near the D/A converter.

My first guess is that -5V is derived from the -15V supply.  If that's
true, flaky +-15V supplies will almost guarantee a flaky EFC.  Since
your unit was able to lock once, it further suggests that retuning isn't
required.

There's a power supply board bolted to one of the side panels that uses
a couple of DC-DC bricks.  I found some bad solder joints on that
board.  I can't remember the details.  You might want to check that out.

Since these units are microprocessor controlled and include multiple
tests and measurements to ensure that the lock is on the correct signal
peak I don't think it's going to lock to the wrong peak.

You should also be aware that these units use a STEL-1173 chip to drive
the D/A converter.  This chip is infamous for failing after a few
years.  If you search the archives you'll find more info on that topic.
I found a source for this chip a few years ago, but it looks like that
source has dried up.

Ed

On 2017-07-08 10:00 AM, Tom Knox  wrote:
> Hi All;
>
> Does anyone have a data sheet or experience with the Symmetricom C, I 
> have one in a Symmetricom 4065C and the internal diagnostics say it is at the 
> end of it's tuning range. Is there a way to do a coarse manual adjustment, or 
> is it a possibility the Cesium is locking to a side peak? In addition the +- 
> 15 volt supplies have failed to switch on twice during testing, but have 
> switch on after rebooting. On one reboot it locked quickly.
>
> Thanks;
>
> Thomas Knox
>

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Re: [time-nuts] J06 HP-59992A time interval calibrator for HP-531xx counters

[Orin Eman]

$38 is for the wideband  100 - 600MHz PSCJ-2-1W - you'd want the PSCJ-2-1+
which is a little less... $29.20 and no price break until you get 10 of
them.

Looking at the PSCJ-2-1+ datasheet, the "phase imbalance" at the output
ports is about 180 degrees.  How they achieve that, they don't say.


On Sun, Jul 9, 2017 at 10:40 AM, Mark Sims  wrote:

> More like $18 for the simple splitter and $38 for the 180 phase shift
> splitter.
>
> Also, does anybody know if the phase shift splitter shifts the phase on
> both outputs or on only one output.   Different HP docs say different
> things.
>
> 
>
> > The original parts were nothing special!  PSC-2-1 is spec'd at 4 degrees
> max phase unbalance - though typical is a lot less - and seems to be about
> $14
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Re: [time-nuts] J06 HP-59992A time interval calibrator for HP-531xx counters

[Orin Eman]

On Sun, Jul 9, 2017 at 10:55 AM, jimlux  wrote:

> On 7/9/17 10:27 AM, Bob kb8tq wrote:
>
>> Hi
>>
>> People *have* been known to sort MiniCircuits parts and use the “extras”
>> in
>> something else. A certain major oscillator manufacturer once bought a
>> bunch
>> of RPD-1’s , sorted them for the “one in a hundred” examples, and then
>> returned
>> the rest for credit…… Somehow I doubt HP didi it quite that way.
>>
>>
> Some manufacturers will cherry pick for you.  Maybe the datasheet says
> gain is 14 to 18 dB, and you order a batch that you want to be 15.5-16.5
> dB.. They'll pick those out, but of course, now the remainder have a hole
> in the distribution.  Particularly when you're buying high-rel or space
> grade, where they have to 100% test anyway.



Right, but there is nothing to indicate there is anything special going on
in this case.  The theory of operation section of the manual states that
the splitters provide "nearly" in-phase and "nearly" out-of-phase signals
without defining "nearly".  It does not sound like it's critical and to me,
it sounds like they are acknowledging that there are phase mismatches
through the splitters.

Then going on to the other link I posted:

http://www.g8wrb.org/data///HP/Better_than_100_ps_Accuracy_in_HP_5370B_Time_Interval_Measurements_Through_Bias_Error_Reduction.pdf

It accounts for the individual delays through the splitters/cables and
shows how they are eliminated by doing multiple measurements and solving
the resulting simultaneous equations.

Indeed, the programs in the J06's manual mention that 'cable' mismatches
(presumable phase mismatches) are included in the calibration constants and
the same cables should be used for doing actual measurements: (the
formatting did not survive and I fixed some obvious OCR errors)

40 ! THIS PROGRAM EXECUTES THE CALIBRATION ALGORITHM DESCRIBED IN D. CHU'S
50 ! PAPER "CALIBRATION OF SYSTEMATIC ERRORS IN PRECISION TIME-INTERVAL
60 ! COUNTERS", INTERNATIONAL TEST CONFERENCE, PHILADELPHIA, 1985;
70 !
80 ! SET-UP PROCEDURE
90 ! 1) CONNECT A PULSE SOURCE TO THE INPUT OF CALIBRATOR, 3 DB LARGER
100 ! THAN THE DESIRED SIGNAL TO BE MEASURED AND APPROXIMATELY THE
110 ! THE SAME RISE/FALL TIMES, -50% DUTY-CYCLE, STABLE 1 TO 100 MHz.
120 ! 2) CONNECT A PAIR OF CABLES FROM CALIBRATOR OUTPUTS A & B
130 !  TO COUNTER START & STOP INPUTS RESPECTIVELY
140 ! (NOTE: CABLE MISMATCHES ARE INCLUDED IN THE CALIBRATION CONSTANTS,
150 ! AND SAME CABLES SHOULD BE USED LATER FOR DOING MEASUREMENTS;
160 ! ALSO "CABLES" INCLUDE LINEAR, PASSIVE OR ACTIVE PROBES)
170 ! 3) SET COUNTER TO SEPERATE: DC/50 ohms/Xl/PRESET to BOTH CHANNELS
180 ! 4) HPIB ADDRESSES: COUNTER-707, CALIBRATOR-705
190 ! 5) CONNECT A PRECISE OFFSET VOLTAGE SOURCE TO THE OFFSET INPUT: ENTER
200 ! THE EXACT SAME VALUE WHEN PROMPTED. DEFAULT IS 0.00 VOLT
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Re: [time-nuts] J06 HP-59992A time interval calibrator for HP-531xx counters

[jimlux]

On 7/9/17 10:27 AM, Bob kb8tq wrote:

Hi

People *have* been known to sort MiniCircuits parts and use the “extras” in
something else. A certain major oscillator manufacturer once bought a bunch
of RPD-1’s , sorted them for the “one in a hundred” examples, and then returned
the rest for credit…… Somehow I doubt HP didi it quite that way.



Some manufacturers will cherry pick for you.  Maybe the datasheet says 
gain is 14 to 18 dB, and you order a batch that you want to be 15.5-16.5 
dB.. They'll pick those out, but of course, now the remainder have a 
hole in the distribution.  Particularly when you're buying high-rel or 
space grade, where they have to 100% test anyway.




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[time-nuts] J06 HP-59992A time interval calibrator for HP-531xx counters

[Mark Sims]

More like $18 for the simple splitter and $38 for the 180 phase shift splitter.

Also, does anybody know if the phase shift splitter shifts the phase on both 
outputs or on only one output.   Different HP docs say different things.  



> The original parts were nothing special!  PSC-2-1 is spec'd at 4 degrees
max phase unbalance - though typical is a lot less - and seems to be about
$14
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Re: [time-nuts] J06 HP-59992A time interval calibrator for HP-531xx counters

[Bob kb8tq]

Hi

People *have* been known to sort MiniCircuits parts and use the “extras” in 
something else. A certain major oscillator manufacturer once bought a bunch
of RPD-1’s , sorted them for the “one in a hundred” examples, and then returned
the rest for credit…… Somehow I doubt HP didi it quite that way.

4 degrees at 10 MHz. A LVCMOS inverter has a delay of about 2.5 ns. Delay time
on cheap flip flops is no longer broken out in enough detail to really see how 
they 
are doing. 

Bob

> On Jul 9, 2017, at 1:14 PM, Orin Eman  wrote:
> 
> On Sat, Jul 8, 2017 at 5:15 PM, Mark Sims  wrote:
> 
>> I think the way the fine cal works by checking the the intervals between
>> four different edges that a lot of asymmetries in the signals are nulled
>> out in the software.
>> 
>> How good are 1:2 180 degree phase shifters at exactly shifting by 180
>> degrees?   At what cost?
>> 
> 
> 
> The original parts were nothing special!  PSC-2-1 is spec'd at 4 degrees
> max phase unbalance - though typical is a lot less - and seems to be about
> $14.
> 
> https://www.minicircuits.com/pdfs/PSC-2-1.pdf
> https://www.minicircuits.com/pdfs/PSCJ-2-1+.pdf
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Re: [time-nuts] J06 HP-59992A time interval calibrator for HP-531xx counters

[Orin Eman]

On Sat, Jul 8, 2017 at 5:15 PM, Mark Sims  wrote:

> I think the way the fine cal works by checking the the intervals between
> four different edges that a lot of asymmetries in the signals are nulled
> out in the software.
>
> How good are 1:2 180 degree phase shifters at exactly shifting by 180
> degrees?   At what cost?
>


The original parts were nothing special!  PSC-2-1 is spec'd at 4 degrees
max phase unbalance - though typical is a lot less - and seems to be about
$14.

https://www.minicircuits.com/pdfs/PSC-2-1.pdf
https://www.minicircuits.com/pdfs/PSCJ-2-1+.pdf
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Re: [time-nuts] J06 HP-59992A time interval calibrator for HP-531xx counters

[Bob kb8tq]

Hi


> On Jul 9, 2017, at 9:35 AM, Francesco Messineo  
> wrote:
> 
> On Sun, Jul 9, 2017 at 2:15 AM, Mark Sims  wrote:
> 
>> 
>> So far my design is tending towards:  10MHz ref input -> Minicircuits 
>> doubler -> Wenzel squarer -> 74AC74 divider -> 74AC04 buffer -> level 
>> shifter.  The doubler/divider might not be needed,  but I think it will give 
>> a more symmetric output.  I might include a space for a 10 MHz TTL 
>> oscillator for non time-nut users... hopefully it might be stable enough 
>> over the short time interval for a cal measurement cycle.
> 
> 
> once upon a time, I was experimenting with digital signals to derive
> stable RF transverter
> LOs. I've "found" that feeding a XOR gate with a signal and his
> replica delayed by 2 inverters
> did result in a crude frequency doubler (well it's rather an edge
> detector).

You can do the same thing with a filter on one input of the XOR. Tuning the 
filter for best 
symmetry is fairly easy. Watching the result on a spectrum analyzer usually is 
quickest. 

Bob


> Since I was going to use the double frequency just to drive
> a divider by two, the actual duty cycle out of the doubler didn't
> matter.
> 
> HTH
> Frank
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Re: [time-nuts] J06 HP-59992A time interval calibrator for HP-531xx counters

[Bruce Griffiths]

With a sinewave input LF feedback from the 74AC04 output to the shaper inputs 
could be used to regulate the output duty cycle by adjusting the switching 
threshold. However ensuring that the input amplitude is sufficiently large to 
override potential LF oscillation. The LF feedback will also compensate for 
delay asymmetry in the 74AC04 as well.

The output transition times of ACMOS is relatively slow compared to modern 
LVCMOS parts.  

Bruce 
> On 09 July 2017 at 12:15 Mark Sims  wrote:
> 
> 
> I think the way the fine cal works by checking the the intervals between four 
> different edges that a lot of asymmetries in the signals are nulled out in 
> the software.
> 
> How good are 1:2 180 degree phase shifters at exactly shifting by 180 
> degrees?   At what cost?   
> 
> Also coax and RF relays cost a lot.   Pretty soon your BOM cost is over what 
> a 59992A will run... assuming you can find one.
> 
> So far my design is tending towards:  10MHz ref input -> Minicircuits doubler 
> -> Wenzel squarer -> 74AC74 divider -> 74AC04 buffer -> level shifter.  The 
> doubler/divider might not be needed,  but I think it will give a more 
> symmetric output.  I might include a space for a 10 MHz TTL oscillator for 
> non time-nut users... hopefully it might be stable enough over the short time 
> interval for a cal measurement cycle.
> 
> For the gain cal an 5V LM4040 (or other) reference.   Routing signals to the 
> output BNC's via 2P4T slide switches.  The slide switches might be a weak 
> link... but they are less than 50 cents each.  Whatever, it should beat the 
> pants off doing just the "quick TI cal"
> 
> The reason I started looking into this is that I want to upgrade the old 
> firmware to a much newer version that allows the comma separators in the 
> decimal digits.   Upgrading the firmware requires a new calibration.
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Re: [time-nuts] J06 HP-59992A time interval calibrator for HP-531xx counters

[Francesco Messineo]

On Sun, Jul 9, 2017 at 2:15 AM, Mark Sims  wrote:

>
> So far my design is tending towards:  10MHz ref input -> Minicircuits doubler 
> -> Wenzel squarer -> 74AC74 divider -> 74AC04 buffer -> level shifter.  The 
> doubler/divider might not be needed,  but I think it will give a more 
> symmetric output.  I might include a space for a 10 MHz TTL oscillator for 
> non time-nut users... hopefully it might be stable enough over the short time 
> interval for a cal measurement cycle.


once upon a time, I was experimenting with digital signals to derive
stable RF transverter
LOs. I've "found" that feeding a XOR gate with a signal and his
replica delayed by 2 inverters
did result in a crude frequency doubler (well it's rather an edge
detector). Since I was going to use the double frequency just to drive
a divider by two, the actual duty cycle out of the doubler didn't
matter.

HTH
Frank
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[time-nuts] J06 HP-59992A time interval calibrator for HP-531xx counters

[Mark Sims]

I think the way the fine cal works by checking the the intervals between four 
different edges that a lot of asymmetries in the signals are nulled out in the 
software.

How good are 1:2 180 degree phase shifters at exactly shifting by 180 degrees?  
 At what cost?   

Also coax and RF relays cost a lot.   Pretty soon your BOM cost is over what a 
59992A will run... assuming you can find one.

So far my design is tending towards:  10MHz ref input -> Minicircuits doubler 
-> Wenzel squarer -> 74AC74 divider -> 74AC04 buffer -> level shifter.  The 
doubler/divider might not be needed,  but I think it will give a more symmetric 
output.  I might include a space for a 10 MHz TTL oscillator for non time-nut 
users... hopefully it might be stable enough over the short time interval for a 
cal measurement cycle.

For the gain cal an 5V LM4040 (or other) reference.   Routing signals to the 
output BNC's via 2P4T slide switches.  The slide switches might be a weak 
link... but they are less than 50 cents each.  Whatever, it should beat the 
pants off doing just the "quick TI cal"

The reason I started looking into this is that I want to upgrade the old 
firmware to a much newer version that allows the comma separators in the 
decimal digits.   Upgrading the firmware requires a new calibration.
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Re: [time-nuts] J06 HP-59992A time interval calibrator for HP-531xx counters

[Bob kb8tq]

Hi

A splitter with a phase error of < 1 degree at exactly 10 MHz is pretty simple 
to build. It’s mostly 
a matter of how much you want to spend on the splitter. Network analyzers can 
be calibrated to 
measure it. You can poke at a part to get it “right”. The same thing is true on 
phase shifters. As
you add up mismatch errors things get a bit weird, but it’s a single frequency 
not broadband. 
This is the old HP buying parts for a calibrator. Who knows what the budget 
was, or how much
thought went into it.

Bob

> On Jul 9, 2017, at 12:41 AM, Orin Eman  wrote:
> 
> FWIW, the "Theory" section here may help:
> 
> http://www.g8wrb.org/data///HP/Better_than_100_ps_Accuracy_in_HP_5370B_Time_Interval_Measurements_Through_Bias_Error_Reduction.pdf
> 
> Phase errors through the splitters seem to be taken into account.
> 
> The J06-59992A manual merely claims 100ps absolute accuracy is possible
> with the 5370A/B.
> 
> 
> 
> On Sat, Jul 8, 2017 at 7:48 PM, Bob kb8tq  wrote:
> 
>> Hi
>> 
>> Based on a quick read of the use of the device, they seem to be relying on
>> it to be << 100 ps
>> off from “ideal”.  How much it being non-ideal matters …. not clear. If
>> you are correcting for various errors
>> and eliminating both unknown source errors and destination errors it
>> likely gets messy.
>> 
>> Bob
>> 
>>> On Jul 8, 2017, at 9:14 PM, Tom Van Baak  wrote:
>>> 
>>> I knew we had talked about this before:
>>> https://www.febo.com/pipermail/time-nuts/2006-August/021649.html
>>> 
>>> The J06-59992A manual, schematic, app note, and patent are here:
>>> http://rubidium.dyndns.org/~magnus/instruments/hp/J06-59992A/
>>> 
>>> It was designed for the hp 5370 (20 ps) so perhaps the tolerances are
>> less stringent if only used for hp 53132 (150 ps). Maybe one of you RF guys
>> can tell from the schematic?
>>> 
>>> Mark writes:
 Yes, they do show up...  but usually for big-ish bucks.   I want to
>> build a small affordable replacement that anybody with a 531xx can have.
>>> 
>>> I don't recall them being expensive at all, just unusual. But making a
>> modern one for time nuts is a great idea -- both 5370 and 53131/53132
>> users. Also, when someone gets around to creating a smart analog front-end
>> to John's TAPR TICC board, your 59992A clone will come in handy.
>>> 
>>> Note also this recent document by Bill Riley:
>>> 
>>> http://www.stable32.com/A%20High-Resolution%20Time%
>> 20Interval%20Counter%20Using%20the%20TAPR%20TADD-2%20and%
>> 20TICC%20Modules.pdf
>>> 
>>> Hal writes:
 What does "good" mean?
 I'd expect the variations due to power or temperature would be easy to
>> measure.
 Delay through classic CMOS is linear with absolute temperature and
>> inverse linear with supply voltage.
>>> 
>>> When John created the TAPR TADD-2-mini board I tested the jitter using a
>> TimePod (integrated phase noise mode). I'm looking for the web page or
>> email now, but I recall it was under 2 ps. This is partly due to the fact
>> that the PIC 12F is a fully synchronous MCU; no tricks with double clock
>> edges or PLL's.
>>> 
>>> /tvb
>>> 
>>> 
>>> - Original Message -
>>> From: "Bruce Griffiths" 
>>> To: "Mark Sims" ; "Discussion of precise time and
>> frequency measurement" 
>>> Sent: Saturday, July 08, 2017 4:48 PM
>>> Subject: Re: [time-nuts] J06 HP-59992A time interval calibrator for
>> HP-531xx counters
>>> 
>>> 
 A run of the mill 2 way power splitter has better than 10ps phase
>> matching at 100MHz there are few digital devices that offer that degree of
>> matching at best they are usually 10x worse.
 
 Bruce
 
> 
>   On 09 July 2017 at 06:58 Mark Sims  wrote:
> 
>   Yes, they do show up... but usually for big-ish bucks. I want to
>> build a small affordable replacement that anybody with a 531xx can have.
> 
>   My design is currently leaning towards a board with the clock
>> generator and a 5V reference for the gain calibration (they spec 5V +/-
>> 1mV). I was going to use a couple of 2P4T slide switches to route open
>> circuit, 5V, normal clock, and inverted clock to the two output connectors.
> 
>   I think the cost to build would be in the $20 range and fit on a
>> 2x2" or so circuit board... certainly more attractive than a $500 big
>> ancient box with unobtainium parts in it. The board should be able to
>> perform all the calibration steps for the counter.
> 
>   I don't think the signal requirements are super critical. They are
>> using 1:2 splitters and splitter/180 degree phase shifters and relays to
>> generate the output signals passively from the inputs. I think a digital
>> clock generator would be a LOT more accurate than those phase shifters.
> 
>   
> 
>>> 
>>   Actually, you can get J06 HP-59992A calibrators on eBay.
>> 
>>> 
>>>