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

[Mark Sims]

To do a full and proper calibration of the HP-53131/53132/53181 counters you need a J06 HP-59992A time interval calibrator... lots of luck finding one of those. Looking at the manual, it is actually a fairly simple device which can be greatly simplified for the task of calibrating a 531XX counter.

The main task is to generate 10 MHz square waves with 50% duty cycle. Four versions of the signal are generated (two positive and two with inverted phase). One of four combos of these signals (P1-P2, P2-P1, N1-N2, and N2-N1) are driven to two output connectors. The 59992A uses splitters and phase shifters to generate the signals and can handle analog signals. The 531xx cal uses square waves so those signals can be generated digitally.

My first idea is to take a 20 MHz oscillator and divide it by two to get a 50% duty cycle. One could also do something like squaring a 10 MHz osc with something like the Wenzel squarer... that would provide a more stable signal frequency wise but that might add some asymmetries to the signal. Feeding the 10 Mhz osc through a doubler and dividing the squared signal might provide the best solution.

The 531xx cal procedure uses a +/- 0.50V signal. I need a simple and cheap circuit to level shift the TTL signal to +/- 0.50V It probably needs clean, stable, fast edges and able to drive a 50 ohm load (the manuals don't specify the required edge rates and load). Any ideas for a suitable level shifter / buffer? It would also be super nice if it could work from a single supply...

Also, if such a cal board was laid out would there be any interest in making it available for others to build?
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[Bob kb8tq]

Hi

This may be “inside” the envelope for something like a PIC. If not it’s a pretty
easy task for any of the sub $10 FPGA boards. Given the relatively small
audience, tacking an extra connector or three onto something might be the
better option.

The big unknown (at least to me) is how close the signals need to be to ideal.
If a few ns is “ok” it’s an easy task. If the spec is < 10 ps … not quite as easy.
My guess is the 59992A is overkill, but to what degree?

Bob

Post by Mark Sims
To do a full and proper calibration of the HP-53131/53132/53181 counters you need a J06 HP-59992A time interval calibrator... lots of luck finding one of those. Looking at the manual, it is actually a fairly simple device which can be greatly simplified for the task of calibrating a 531XX counter.
The main task is to generate 10 MHz square waves with 50% duty cycle. Four versions of the signal are generated (two positive and two with inverted phase). One of four combos of these signals (P1-P2, P2-P1, N1-N2, and N2-N1) are driven to two output connectors. The 59992A uses splitters and phase shifters to generate the signals and can handle analog signals. The 531xx cal uses square waves so those signals can be generated digitally.
My first idea is to take a 20 MHz oscillator and divide it by two to get a 50% duty cycle. One could also do something like squaring a 10 MHz osc with something like the Wenzel squarer... that would provide a more stable signal frequency wise but that might add some asymmetries to the signal. Feeding the 10 Mhz osc through a doubler and dividing the squared signal might provide the best solution.
The 531xx cal procedure uses a +/- 0.50V signal. I need a simple and cheap circuit to level shift the TTL signal to +/- 0.50V It probably needs clean, stable, fast edges and able to drive a 50 ohm load (the manuals don't specify the required edge rates and load). Any ideas for a suitable level shifter / buffer? It would also be super nice if it could work from a single supply...
Also, if such a cal board was laid out would there be any interest in making it available for others to build?
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[Tom Van Baak]

Post by Mark Sims
lots of luck finding one of those

Actually, you can get J06 HP-59992A calibrators on eBay. You might have to wait a while but I've seen them frequently over time. Note that eBay has an automatic search notification feature so you can get email when one shows up.

If you want I'll lend you one of my J06 HP-59992A for your calibration. Contact me off-list.

Post by Mark Sims
If a few ns is “ok” it’s an easy task. If the spec is < 10 ps … not quite as easy.

The PIC dividers are good to a couple ps. I suspect the larger issue is the PCB and wiring design.

/tvb

----- Original Message -----
From: "Mark Sims" <***@hotmail.com>
To: <time-***@febo.com>
Sent: Saturday, July 08, 2017 6:31 AM
Subject: [time-nuts] J06 HP-59992A time interval calibrator for HP-531xxcounters

Post by Mark Sims
To do a full and proper calibration of the HP-53131/53132/53181 counters you need a J06 HP-59992A time interval calibrator... lots of luck finding one of those. Looking at the manual, it is actually a fairly simple device which can be greatly simplified for the task of calibrating a 531XX counter.
The main task is to generate 10 MHz square waves with 50% duty cycle. Four versions of the signal are generated (two positive and two with inverted phase). One of four combos of these signals (P1-P2, P2-P1, N1-N2, and N2-N1) are driven to two output connectors. The 59992A uses splitters and phase shifters to generate the signals and can handle analog signals. The 531xx cal uses square waves so those signals can be generated digitally.
My first idea is to take a 20 MHz oscillator and divide it by two to get a 50% duty cycle. One could also do something like squaring a 10 MHz osc with something like the Wenzel squarer... that would provide a more stable signal frequency wise but that might add some asymmetries to the signal. Feeding the 10 Mhz osc through a doubler and dividing the squared signal might provide the best solution.
The 531xx cal procedure uses a +/- 0.50V signal. I need a simple and cheap circuit to level shift the TTL signal to +/- 0.50V It probably needs clean, stable, fast edges and able to drive a 50 ohm load (the manuals don't specify the required edge rates and load). Any ideas for a suitable level shifter / buffer? It would also be super nice if it could work from a single supply...
Also, if such a cal board was laid out would there be any interest in making it available for others to build?

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[Bob kb8tq]

Hi

Post by Tom Van Baak

Post by Mark Sims
lots of luck finding one of those

Actually, you can get J06 HP-59992A calibrators on eBay. You might have to wait a while but I've seen them frequently over time. Note that eBay has an automatic search notification feature so you can get email when one shows up.
If you want I'll lend you one of my J06 HP-59992A for your calibration. Contact me off-list.

Post by Mark Sims
If a few ns is “ok” it’s an easy task. If the spec is < 10 ps … not quite as easy.

The PIC dividers are good to a couple ps. I suspect the larger issue is the PCB and wiring design.

The jitter on the outputs is indeed good to that level. I’d be surprised if the “DC offset” is that good.
Been wrong before …..

Why do I suspect that data will be forthcoming? :)

Bob

Post by Tom Van Baak
/tvb
----- Original Message -----
Sent: Saturday, July 08, 2017 6:31 AM
Subject: [time-nuts] J06 HP-59992A time interval calibrator for HP-531xxcounters

Post by Mark Sims
To do a full and proper calibration of the HP-53131/53132/53181 counters you need a J06 HP-59992A time interval calibrator... lots of luck finding one of those. Looking at the manual, it is actually a fairly simple device which can be greatly simplified for the task of calibrating a 531XX counter.
The main task is to generate 10 MHz square waves with 50% duty cycle. Four versions of the signal are generated (two positive and two with inverted phase). One of four combos of these signals (P1-P2, P2-P1, N1-N2, and N2-N1) are driven to two output connectors. The 59992A uses splitters and phase shifters to generate the signals and can handle analog signals. The 531xx cal uses square waves so those signals can be generated digitally.
My first idea is to take a 20 MHz oscillator and divide it by two to get a 50% duty cycle. One could also do something like squaring a 10 MHz osc with something like the Wenzel squarer... that would provide a more stable signal frequency wise but that might add some asymmetries to the signal. Feeding the 10 Mhz osc through a doubler and dividing the squared signal might provide the best solution.
The 531xx cal procedure uses a +/- 0.50V signal. I need a simple and cheap circuit to level shift the TTL signal to +/- 0.50V It probably needs clean, stable, fast edges and able to drive a 50 ohm load (the manuals don't specify the required edge rates and load). Any ideas for a suitable level shifter / buffer? It would also be super nice if it could work from a single supply...
Also, if such a cal board was laid out would there be any interest in making it available for others to build?

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[Charles Steinmetz]

Post by Mark Sims
I need a simple and cheap circuit to level shift the TTL signal to +/- 0.50V
It probably needs clean, stable, fast edges and able to drive a 50 ohm load

See attached. The resistor values shown assume that the source is a
0-5v rectangular signal able to source +/- 10mA with negligible voltage
drop (a single 74AC or 74HC gate will do that). The edges will be as
fast as the source. The symmetry and stability will be the same, as well.

Best regards,

Charles

[Mark Sims]

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.

----------------

Post by Tom Van Baak
Actually, you can get J06 HP-59992A calibrators on eBay.

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[Bruce Griffiths]

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

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.
----------------

Post by Tom Van Baak
Actually, you can get J06 HP-59992A calibrators on eBay.
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[Tom Van Baak]

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?

Post by Mark Sims
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

Post by Mark Sims
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" <***@xtra.co.nz>
To: "Mark Sims" <***@hotmail.com>; "Discussion of precise time and frequency measurement" <time-***@febo.com>
Sent: Saturday, July 08, 2017 4:48 PM
Subject: Re: [time-nuts] J06 HP-59992A time interval calibrator for HP-531xx counters

Post by Mark Sims
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

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.
----------------

Post by Tom Van Baak
Actually, you can get J06 HP-59992A calibrators on eBay.

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and follow the instructions there.

[Bob kb8tq]

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

Post by Tom Van Baak
https://www.febo.com/pipermail/time-nuts/2006-August/021649.html
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?

Post by Mark Sims
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.
http://www.stable32.com/A%20High-Resolution%20Time%20Interval%20Counter%20Using%20the%20TAPR%20TADD-2%20and%20TICC%20Modules.pdf

Post by Mark Sims
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 -----
Sent: Saturday, July 08, 2017 4:48 PM
Subject: Re: [time-nuts] J06 HP-59992A time interval calibrator for HP-531xx counters

Post by Mark Sims
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

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.
----------------

Post by Tom Van Baak
Actually, you can get J06 HP-59992A calibrators on eBay.

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[Orin Eman]

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.

Post by Bob kb8tq
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

Post by Tom Van Baak
https://www.febo.com/pipermail/time-nuts/2006-August/021649.html
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?

Post by Tom Van Baak

Post by Mark Sims
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.

Post by Tom Van Baak
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.

Post by Tom Van Baak
http://www.stable32.com/A%20High-Resolution%20Time%

20Interval%20Counter%20Using%20the%20TAPR%20TADD-2%20and%
20TICC%20Modules.pdf

Post by Tom Van Baak

Post by Mark Sims
What does "good" mean?
I'd expect the variations due to power or temperature would be easy to

measure.

Post by Tom Van Baak

Post by Mark Sims
Delay through classic CMOS is linear with absolute temperature and

inverse linear with supply voltage.

Post by Tom Van Baak
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.

Post by Tom Van Baak
/tvb
----- Original Message -----
Sent: Saturday, July 08, 2017 4:48 PM
Subject: Re: [time-nuts] J06 HP-59992A time interval calibrator for

HP-531xx counters

Post by Tom Van Baak

Post by Mark Sims
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.

Post by Tom Van Baak

Post by Mark Sims
Bruce

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.

Post by Tom Van Baak

Post by Mark Sims

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.

Post by Tom Van Baak

Post by Mark Sims

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.

Post by Tom Van Baak

Post by Mark Sims

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.

Post by Tom Van Baak

Post by Mark Sims

----------------

Post by Tom Van Baak
Actually, you can get J06 HP-59992A calibrators on eBay.

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mailman/listinfo/time-nuts

Post by Tom Van Baak
and follow the instructions there.

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mailman/listinfo/time-nuts
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[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

Post by Orin Eman
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.

Post by Bob kb8tq
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

Post by Tom Van Baak
https://www.febo.com/pipermail/time-nuts/2006-August/021649.html
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?

Post by Tom Van Baak

Post by Mark Sims
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.

Post by Tom Van Baak
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.

Post by Tom Van Baak
http://www.stable32.com/A%20High-Resolution%20Time%

20Interval%20Counter%20Using%20the%20TAPR%20TADD-2%20and%
20TICC%20Modules.pdf

Post by Tom Van Baak

Post by Mark Sims
What does "good" mean?
I'd expect the variations due to power or temperature would be easy to

measure.

Post by Tom Van Baak

Post by Mark Sims
Delay through classic CMOS is linear with absolute temperature and

inverse linear with supply voltage.

Post by Tom Van Baak
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.

Post by Tom Van Baak
/tvb
----- Original Message -----
Sent: Saturday, July 08, 2017 4:48 PM
Subject: Re: [time-nuts] J06 HP-59992A time interval calibrator for

HP-531xx counters

Post by Tom Van Baak

Post by Mark Sims
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.

Post by Tom Van Baak

Post by Mark Sims
Bruce

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.

Post by Tom Van Baak

Post by Mark Sims

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.

Post by Tom Van Baak

Post by Mark Sims

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.

Post by Tom Van Baak

Post by Mark Sims

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.

Post by Tom Van Baak

Post by Mark Sims

----------------

Post by Tom Van Baak
Actually, you can get J06 HP-59992A calibrators on eBay.

_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/

mailman/listinfo/time-nuts

Post by Tom Van Baak
and follow the instructions there.

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[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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[Francesco Messineo]

Post by Mark Sims
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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[Bob kb8tq]

Hi

Post by Francesco Messineo

Post by Mark Sims
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

Post by Francesco Messineo
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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[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

Post by 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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[Orin Eman]

Post by 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?

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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[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

Post by Orin Eman

Post by 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?

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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[jimlux]

Post by 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.

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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[Orin Eman]

Post by jimlux

Post by 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.

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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[Poul-Henning Kamp]

--------

Post by jimlux

Post by 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.

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.

I've been told by somebody from HPs manufacturing in Europe that
there were one or two "magic" components where the manufacturer
would send their entire production to HP.

HP would test, measure and sort into four bins: "Failed", "Good",
"Really good" and "HP".

The first three bins got shipped back to the manufacturer.

He suspected that back at the manufacturer, the "Really good"
got a "MIL-GRADE" stamp :-)

[Orin Eman]

FWIW Re: the relays. I worked through the Omron discontinuation notices
for the first relay (I figure the original was a G5Y series, not GSY as in
the manual) and it looks like the G6K series, easily available at Mouser
and about $4 each would work, though you'd have to use a DPDT.

The other two relays are cute little TO5 relays from Teledyne - 412 or 712
series, 12V coil. The 712-12 will cost $35 at Mouser. Ouch.

From reading the paper and the Basic program, the _critical_ part of the
circuit is getting the delays with the outputs swapped exactly the same as
the delays with the outputs unswapped. A non-trivial task since the traces
are all 50 ohm stripline. (Or so the manual says - a picture of both sides
of the original PCB would help immensely in determining how critical the
layout is.)

(Phase differences due to the splitters are eliminated by taking a reading
with the outputs unswapped, then with the outputs swapped. Taking half the
sum of these two readings eliminates the phase error due to the splitter.
At least that's what the Basic program does; the description in the paper
is slightly different, but the equation simplifies to the same thing.)
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--------

Post by Mark Sims
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.

The crucial feature of the 59992A was support for DC-bias, and
that seems to have dictated its design.

If you have no need for DC-bias, an 8-pin microcontroller with a
stable crystal and suitable resistor networks on the outputs will
do fine.

TI measurements on top of DC-bias was important in development and
manufacturing of disk drives: Measurement of jitter of mechanical
origin must happen on the analog side of the differential read
amplifier, which usually balances a couple of volts up for cost
reasons.

[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.

------------

Post by Orin Eman
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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[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.

Post by 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.
------------

Post by Orin Eman
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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