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Re: Another 3GHz 53132-68003 Chanel 3 option design for the 53131A and 53132A

 

No worries -- this was all new stuff to all of us at one time or another.

As for black magic, it's got that rep, sure, but after a while you realize that it's all pretty straightforward. All you need is a wizard's hat and a chicken. Adjust the latter as necessary.

-- Cheers,
Tom

--
Prof. Thomas H. Lee
Faculty Co-Director, SystemX Alliance
Director, Stanford-Samsung Research Initiative

Allen Ctr., Rm. 205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070

On 10/10/2023 12:46 AM, Jared Cabot via groups.io wrote:
It makes sense. I'm still learning this black magic high frequency stuff, so I may have a few more basic-level questions to come. Bear with me.... :)
Re: Another 3GHz 53132-68003 Chanel 3 option design for the 53131A and 53132A

 

On Tue, Oct 10, 2023 at 11:10 AM, Ed Breya wrote:
You don't have to care about the diode reverse voltage ratings - when anti-parallel, each can only see forward voltages, unless the current rating is exceeded. What matters is that (indicates the RF power it can clamp at the input), and the zero-bias capacitance (for speed).
Of course.... That makes perfect sense.


The prescaler inputs are symmetric. You can treat it as a differential amplifier, and put the input signal to either one, while the other is bypassed - it will toggle one opposite edges if swapped. The ECL DC bias (Vbb) is usually developed by some sort of internal regulator circuitry, and each input connects to it through some medium resistance maybe in the hundreds of ohms range. You can put the DC bias into either one, just like the signal. What you want to do is upset the bias level a little bit to reduce the gain. HP used a selected R value for pulling the bias, and you can do the same if you can figure out how much is right. If you're designing for "production," it may be better to use a fixed resistor in series with a pot, to effectively select a value that's right for the particular part.
Yeah, this application doesn't care if the signal is inverted so we are free to do what we want.
This one will be just a small run to cover my initial costs so a selected resistor would be fine, and then the full design files will be released, so maybe I'll make provision in v2.0 for a selected resistor and a trimpot depending on the builders preference.


You can get some good ideas by studying the old ECL parts and documents. My favorite info source for this is the Motorola from the 1980s - I think the data book was called "MECL-III" family. Later generations like 10H and up started improving the performance, always tending faster, and with temperature-compensated Vbb,, lower operating voltage, and more function variety. A good proxy for a prescaler input section is the 116 or 216, for instance. These basic models extend from MC10216, to 10H216, to very high speed into the microwave 100E series and such. The 116 and 216 are triple line receivers, among the most highly used types, for interfacing small signals to ECL. Picture a single part with the three stages cascaded for high gain, so you can toggle the following flip-flops with mV input signals - if you have it biased right. The line receiver type parts almost always include access to the Vbb for setting up these scenarios with external resistors. The prescalers have the same setup with internal resistors, and don't provide access to Vbb. But, you can measure it - it's roughly the DC voltage present on the input pins.

Ed
I'll check that out, thanks!



On Tue, Oct 10, 2023 at 12:13 PM, Tom Lee wrote:
Hi Jared,

I assume that a decimal point went AWOL and that you meant 0.26pF. I
have never seen a 26pF diode with a 4V breakdown -- not because it's
impossible, but because there is no market for one.
Ah yup, a typo there, 0.26pF is what I meant. :D


A good guide for how much is too much is to calculate the capacitance
reactance at the highest frequency, and compare it to what shunts it in
that circuit (50 ohms, e.g.). At 1GHz, say, a 1pF cap presents about a
160 ohm reactance, which is larger, but not very much so, than 50 ohms.
At 10GHz, it's 16 ohms, which begins to look more like a short compared
to 50 ohms. You get the idea.

-- Cheers
Tom
It makes sense. I'm still learning this black magic high frequency stuff, so I may have a few more basic-level questions to come. Bear with me.... :)



Thanks!
Jared
Re: Another 3GHz 53132-68003 Chanel 3 option design for the 53131A and 53132A

 

Hi Jared,

I assume that a decimal point went AWOL and that you meant 0.26pF. I have never seen a 26pF diode with a 4V breakdown -- not because it's impossible, but because there is no market for one.

A good guide for how much is too much is to calculate the capacitance reactance at the highest frequency, and compare it to what shunts it in that circuit (50 ohms, e.g.). At 1GHz, say, a 1pF cap presents about a 160 ohm reactance, which is larger, but not very much so, than 50 ohms. At 10GHz, it's 16 ohms, which begins to look more like a short compared to 50 ohms. You get the idea.

-- Cheers
Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070

On 10/9/2023 6:04 PM, Jared Cabot via groups.io wrote:
And secondly, the diode selection.. I see that the (obsolete) diodes that HP chose have a capacitance of 26pF, but a reverse voltage rating of 4V.
Re: Another 3GHz 53132-68003 Chanel 3 option design for the 53131A and 53132A

 

You don't have to care about the diode reverse voltage ratings - when anti-parallel, each can only see forward voltages, unless the current rating is exceeded. What matters is that (indicates the RF power it can clamp at the input), and the zero-bias capacitance (for speed).

The prescaler inputs are symmetric. You can treat it as a differential amplifier, and put the input signal to either one, while the other is bypassed - it will toggle one opposite edges if swapped. The ECL DC bias (Vbb) is usually developed by some sort of internal regulator circuitry, and each input connects to it through some medium resistance maybe in the hundreds of ohms range. You can put the DC bias into either one, just like the signal. What you want to do is upset the bias level a little bit to reduce the gain. HP used a selected R value for pulling the bias, and you can do the same if you can figure out how much is right. If you're designing for "production," it may be better to use a fixed resistor in series with a pot, to effectively select a value that's right for the particular part.

You can get some good ideas by studying the old ECL parts and documents. My favorite info source for this is the Motorola from the 1980s - I think the data book was called "MECL-III" family. Later generations like 10H and up started improving the performance, always tending faster, and with temperature-compensated Vbb,, lower operating voltage, and more function variety. A good proxy for a prescaler input section is the 116 or 216, for instance. These basic models extend from MC10216, to 10H216, to very high speed into the microwave 100E series and such. The 116 and 216 are triple line receivers, among the most highly used types, for interfacing small signals to ECL. Picture a single part with the three stages cascaded for high gain, so you can toggle the following flip-flops with mV input signals - if you have it biased right. The line receiver type parts almost always include access to the Vbb for setting up these scenarios with external resistors. The prescalers have the same setup with internal resistors, and don't provide access to Vbb. But, you can measure it - it's roughly the DC voltage present on the input pins.

Ed
Re: Another 3GHz 53132-68003 Chanel 3 option design for the 53131A and 53132A

 

Alrighty, I've swapped to a SOT-89 package for the vreg, I chose an which has a bit more thermal headroom.
It also does away with the tantalum caps and uses two 1uF ceramic caps instead, so nice for a little BOM and cost reduction.

So two more questions remain.. That biasing of the prescaler and also I have yet to nail down the protection diode selection.

I was wondering about that fancy stuff going on in the inverted input of the prescaler, I thought it must have had a reason like the biasing, but datasheets don't make much mention of it...
How would one go about getting into the ballpark for the design of that network of parts before empirical testing to nail the values?
I have a handful of the prescaler chips here, so I could rig something up pretty easily.

And secondly, the diode selection.. I see that the (obsolete) diodes that HP chose have a capacitance of 26pF, but a reverse voltage rating of 4V.
How can I figure out an upper limit to the diode capacitance? higher reverse breakdown voltage means higher capacitance, so it seems to be a trade-off between durability against user abuse and performance. :D


Thanks!
Jared
Re: help repairing 8133a

 

开云体育

Interesting that the pattern is fractal -- every octave looks like every other octave. So there's consistency in the error pattern.

-- Tom
-- 
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070
On 10/9/2023 5:46 PM, Xtremexp wrote:

Yeah,

I did ran the command and I get following, so It seems calibration is OK (it is linear)

:DIAG:CAL:YIG?
+2.02000E+09,+9.55000E+02,+2.56030E+09,+1.54500E+03,+3.02723E+09,+2.05600E+03,+3.49605E+09,+2.56700E+03,+3.95992E+09,+3.07200E+03

I re measured and plotted the set frequency and the output frequency on ch1 (using frequency counter). I see below plot. Yellow trace is the YIG frequency from 2 to 4Ghz (expected) and the blue trace is the actual frequency output, x axis is the set frequency. I measured manually from 33 Mhz to 500Mhz. Its clear that the output frequency has some issues and not linear with set frequency.


I still do not understand how 12 bit DAC translates to the YIG output, May be some bit of DAC is an issue?.

By the way, My timing board was coming from Israel, and due to what's going on over there, it is not certain if I will get it or not.?

If you end up fixing RF relay, then I will follow your pursuit and fix mine also. :)

Thanks alot.
Re: help repairing 8133a

 

Yeah,

I did ran the command and I get following, so It seems calibration is OK (it is linear)

:DIAG:CAL:YIG?
+2.02000E+09,+9.55000E+02,+2.56030E+09,+1.54500E+03,+3.02723E+09,+2.05600E+03,+3.49605E+09,+2.56700E+03,+3.95992E+09,+3.07200E+03

I re measured and plotted the set frequency and the output frequency on ch1 (using frequency counter). I see below plot. Yellow trace is the YIG frequency from 2 to 4Ghz (expected) and the blue trace is the actual frequency output, x axis is the set frequency. I measured manually from 33 Mhz to 500Mhz. Its clear that the output frequency has some issues and not linear with set frequency.


I still do not understand how 12 bit DAC translates to the YIG output, May be some bit of DAC is an issue?.

By the way, My timing board was coming from Israel, and due to what's going on over there, it is not certain if I will get it or not.?

If you end up fixing RF relay, then I will follow your pursuit and fix mine also. :)

Thanks alot.
WTB: US HP 2015 THD Multimeter

 

I’m looking for a HP 2015 THD Multimeter?
looking to spend around $500
or trade for Keithley 2700 w/ 7706 module
Re: help repairing 8133a

 

开云体育

Hi,

?

I found that (calibration YIG.txt) in the old Hp journal, about 8133A. It might be a good idea to check these values.

I used the command =>?????? :DIAG:CAL:YIG?

And the result was ???=>??????? +2.02000E+09,+9.31000E+02,+2.55987E+09,+1.51400E+03,+3.02676E+09,+2.01900E+03,+3.49611E+09,+2.52500E+03,+3.95988E+09,+3.02400E+03

?

?

?

When you change the frequency from 112.5 MHz to 124 MHz and the output frequency remains unchanged at 103.5 MHz...

I would say that the DAC circuitry is at fault and not the YIG, because it would have moved with this change of DC, it could have given the wrong frequency but it would have moved.

?

I would be curious to see the behavior at 225 MHz, the generator should have an output of 207 MHz, and by changing the frequency to 248 MHz the output should maintain at 207 MHz.

This situation requires the DAC to have the same values sent to the YIG, only a divisor after the YIG will change.

?

You will receive a timing board; you will be able to solve this problem.

?

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

?

?

For my part, I will make a frequency precision curve over the entire range of the 8133A. I'm going to reopen my 8133A to try to repair the RF relay again.

?

Regards

:Yves

?

De?: [email protected] <[email protected]> De la part de Xtremexp
贰苍惫辞测é?: 9 octobre 2023 12:41
??: [email protected]
Objet?: Re: [HP-Agilent-Keysight-equipment] help repairing 8133a

?

Thanks Yves,

I checked the operation of frequency counter on external input signal. The frequency counter indeed shows the correct input frequency feed into the external clock input.
This points that either YIG or somewhere near YIG has problem. The frequency error is not minor, for an example, if I set internal clock to112.5MHz, I measure the clock 103.5Mhz and the output frequency stays same (103.5Mhz) even I set the clock to 124Mhz, It seems that in some bands the YIG frequency is both incorrect and not responding to the requested frequency changes.

But in some band (e,g, from 80.7Mhz to 112.4 Mhz), the output frequency is both correct and stable.
I ordered a used timing board from ebay, I hope i can harvest the YIG if it is still functional. wish me a luck.

My unit does not show any other error than E008 (frequency counter error) So I strongly suspect, frequency counter is working OK but output if frequency counter is not correct, throwing error, and because input of the frequency counter is not correct.

I looked into the Channel 1 RF relay, I think we can replace with equivalent part or may be I can open it and have a look, I plan to do it when I open the unit to debug the YIG issue. I will keep you posted.

And Indeed its very difficult to open the unit to have access to the timing board, Its tons of screws :)

Thanks!

calibration YIG.txt
calibration YIG.txt

Re: HP YIG assembly 5086-7096 mixer 5086-7059

 

I've stumbled across this old HP YIG 5086-7096 1.8-4.2GHz oscillator.

Chuck Harris has correctly listed the pinout as seen in the HP86230 plug-in schematics, but that pinout is misleading (wrong), as had the original author already figured out. Thanks also to Rainer DF6NA for providing me the schematics.

Here is the correct pinout, without any doubts, as the YIG happily lives and gives me nominal output:

Pin 1: +20V
Pin 2: FM+ (1.5Ohm)
Pin 3: Main coil (45Ohm)
Pin 4: Main coil
Pin 5: FM-
Pin 6: -10V
Pin 7: -10V
Pin 8: Gnd

Main coil current vs. frequency:
46.8mA ... 2.025GHz (my setup did not allow me to go further down, but I expect it would go to 1.6GHz)
80.0mA ... 3.404GHz
100.0mA ... 4.231GHz

Cheers!
Re: Another 3GHz 53132-68003 Chanel 3 option design for the 53131A and 53132A

 

Ed's absolutely right. At 25C ambient, that's already right at the limit for that package, and you shouldn't assume a 25C ambient for the innards of an instrument.

Use a version in a beefier package.

-- Cheers
Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070

On 10/9/2023 4:43 AM, Ed wrote:
Still think that an SOT-23 package is a bit small for 50mA with a 7V drop.
For a small increase in $$ an SOT-89 or SOT-223 package regulator would be a better choice.
Re: Another 3GHz 53132-68003 Chanel 3 option design for the 53131A and 53132A

 

Just remembered one more thing from something I noticed before, but didn't look closely - had to go back to the original HP circuit to be sure. Take a look at the rather elaborate decoupling circuit they used on the other input (pin 8) to the prescaler. On close inspection, you can see the extra damper R10/C23, and R6 to ground, apparently a factory selected value - that's to shift the DC bias just like I was talking about, except using the opposing input. You can picture it as a differential input. They used ground though, to move it, which works the same way, while I'm more of a purist and go with Vcc, by habit. And of course, R6 had to be determined and selected somehow, to go with the particular IC U5.

Ed
Re: Book draft update

 

Thanks to everybody. I made a mistake leaving the brand on the book mock-up; I masked it (and the 10 Mohm also). Please forget, I will come back when authorized.?
The new download is in lower resolution, so that it is smaller (400 Mb).
Re: Another 3GHz 53132-68003 Chanel 3 option design for the 53131A and 53132A

 

I remember someone mentioned trying a 3 dB attenuator in front, with no effect on oscillation. The oscillation is in the prescaler itself, and it doesn't matter how much gain is ahead of it.

The usual way to inhibit oscillation is to throw the input DC bias out of wack a little bit, with some resistance to Vcc, which is +5V for PECL operation, or ground for regular (N)ECL. This shifts the amplifier chain away from the "ideal" (Vbb) DC bias level, reducing the gain. It can be done experimentally, determined by the particular device input characteristics. A starting R value in the 1k to 10k range should be noticeable. You can monitor the input DC level with a high resistance like 100k tacked to the node, connected to a DVM. The loss in sensitivity can be made up for by more gain in the other amplifiers, if needed.

One thing that might help somewhat, is to use a much larger coupling cap into the input of the prescaler, so the Z there will be dominated by the driving amplifier's characteristics. It could also aggravate it, or just change the frequency - it's another experimental kind of deal. Bigger signal coupling caps throughout can also reduce the lower frequency cutoff, if that's desirable. Most prescalers can count as low as you want if the signal and cap are big enough, and edges fast enough.

Ed.
Re: help repairing 8133a

 

Thanks Yves,

I checked the operation of frequency counter on external input signal. The frequency counter indeed shows the correct input frequency feed into the external clock input.
This points that either YIG or somewhere near YIG has problem. The frequency error is not minor, for an example, if I set internal clock to112.5MHz, I measure the clock 103.5Mhz and the output frequency stays same (103.5Mhz) even I set the clock to 124Mhz, It seems that in some bands the YIG frequency is both incorrect and not responding to the requested frequency changes.

But in some band (e,g, from 80.7Mhz to 112.4 Mhz), the output frequency is both correct and stable.
I ordered a used timing board from ebay, I hope i can harvest the YIG if it is still functional. wish me a luck.

My unit does not show any other error than E008 (frequency counter error) So I strongly suspect, frequency counter is working OK but output if frequency counter is not correct, throwing error, and because input of the frequency counter is not correct.

I looked into the Channel 1 RF relay, I think we can replace with equivalent part or may be I can open it and have a look, I plan to do it when I open the unit to debug the YIG issue. I will keep you posted.

And Indeed its very difficult to open the unit to have access to the timing board, Its tons of screws :)

Thanks!
Re: Another 3GHz 53132-68003 Chanel 3 option design for the 53131A and 53132A

 

I agree with Ed and think it's best to use a heavier regulator, or maybe throw some of the power into a series dropping resistor or Zener diode.

Regarding spurious noise and oscillations, here's something I wrote in time-nuts a few months back:

"It's a bit tricky to use prescalers for arbitrary input signals. As others have mentioned, they self-oscillate when there isn't a valid input signal. This is not only a possible, but nearly certain characteristic due to the (typically) ECL input amplifier being biased right at the logic threshold, followed by lots of gain, then divided by flip-flops. These were typically used in PLL synthesizers over limited frequency ranges, with known, adequate power levels.

If you are counting strong signals at well defined DC levels, you can use ECL directly with proper biasing. For a general purpose counter, you want lots of sensitivity and wide frequency range, so the usual prescaler with self-biasing and AC coupling is a simple way to go. You just have to be aware of the limitations. You can eliminate the oscillation tendency by giving up some sensitivity, but it's easiest to just ignore it unless it causes trouble."

Ed
Wanted:HP 11748A Active Probe System Operating Manual

 

Does anyone have the manual or any info on the HP 11748A Active Probe System??

I can’t seem to find anything.

Drew
Re: Book draft update

 

Hi Gianni,

This is a list of the errors that I found so far. They are typographical ones:

P 19. "Input impedance: 0 MΩ" should be . "Input impedance: 10 MΩ"
P 29. "the input de level" should be "the input DC level" .
P 32. " a narrow band de amplifier" should be " a narrow band DC amplifier.
P 32.? "Frequency of the amplifier is 0.5 ps at the -3 db point." ???
P 45. "basic accuracy of ?3% of reading" should be "basic accuracy of +/- 3% of reading" .
P 45. "floating off-ground to ?500 volts peak" should be "floating off-ground +/- 500 volts peak".
P52. "low to chassis: ? 500 V peak," should be . "low to chassis: +/- 500 V peak," .

Best regards,

Ignacio

El 08/10/2023 a las 20:15, EB4APL via groups.io escribió:

Hi Gianni,

First of all a big thank you for these marvelous books that you have gifted to us.

I want to take to your attention that in the Hewlett Packard one there is an error in page 19, Input impedance should be 10 MOhm instead of 0 MOhm.

Best regards,

Ignacio

--
Este correo electrónico ha sido analizado en busca de virus por el software antivirus de Avast.
www.avast.com
Re: Another 3GHz 53132-68003 Chanel 3 option design for the 53131A and 53132A

 

Still think that an SOT-23 package is a bit small for 50mA with a 7V drop.
For a small increase in $$ an SOT-89 or SOT-223 package regulator would be a better choice.
You can not get much heat out of the SOT-23 or SOT-23-5 regulators due to the small leads.
That may be why they just provide the junction to ambient number in the data sheet.
The larger tab on the SOT-89 and SOT-223 gives them a better heat transfer to the plane, and you want one that has a ground tab, not a input or output tab like some regulators..
I am not sure the low noise aspect of the AP2210 would make much difference here.
Maybe its just my aerospace background taking over here, we usually did not have much room for temperature rise...

As far as the input noise is concerned, I tried a 3dB attenuator at the input and that did not help, so I would assume a high value resistor would not help either.
I found that with at least one nylon standoff the input was stable with no signal..
The board was OK with three of the ground connected standoffs but the 4th one initiated the noise problem.
It was quiet on the bench.

ed
5 files uploaded #file-notice

Group Notification
 

The following files and folders have been uploaded to the Files area of the [email protected] group.

By: Gerald <vk3gm@...>

Description:
Latest documents, uploaded in the YIG folder for the HP-8594E alternative YIG retrofit. 5 files. Excel for people to add/modify and PDF for ref.
11641 - 11660 of 150928