Author Topic: Yet another fast edge pulse generator  (Read 58625 times)

0 Members and 2 Guests are viewing this topic.

Offline Tom45

  • Frequent Contributor
  • **
  • Posts: 299
  • Country: us
Re: Yet another fast edge pulse generator
« Reply #225 on: October 19, 2017, 09:21:31 am »
Wow! The Tek scope reports 30.851912 psec rise time.   :-DD
 

Offline WastelandTek

  • Frequent Contributor
  • **
  • Posts: 359
  • Country: 00
Re: Yet another fast edge pulse generator
« Reply #226 on: October 21, 2017, 05:18:34 am »
I have been to the Electronics Design Show in Coventry (UK) earlier today and dropped by our friends from Tektronix and Pico Technology.

Thanks to James from Tek and Kieran and Trevor from Pico Tech for testing the pulser.  It is not easy to demo your complicated top line equipment live when everybody is watching - especially to test a surprise customer device.  When I have showed up both scopes were set up to run demos for eye pattern tests and TDR but engineers were more than happy to rip the setup apart and connect my unknown DUT - both scopes worked flawlessly and we had great fun.

Tektronix had 33GHz BW, 100Gsps realtime DPO73304SX scope on their stand and the pulser edge speed result was 31ps.

Pico Technology demoed 20GHz BW sampling scope with TDR capability which measured the pulser risetime at 34ps.

Leo

That is really cool!
I'm new here, but I tend to be pretty gregarious, so if I'm out of my lane please call me out.
 

Offline Howardlong

  • Super Contributor
  • ***
  • Posts: 4417
  • Country: gb
Re: Yet another fast edge pulse generator
« Reply #227 on: October 21, 2017, 06:29:18 am »
I realise it might be a bit niche, but a native SMA or 3.5mm version might perform even better!
 

Offline Leo Bodnar

  • Frequent Contributor
  • **
  • Posts: 564
  • Country: gb
Re: Yet another fast edge pulse generator
« Reply #228 on: October 21, 2017, 06:37:46 am »
I realise it might be a bit niche, but a native SMA or 3.5mm version might perform even better!
It would need total redesign to show appreciable improvement.
I have tested SMA version today and apart from subtle changes it did not have much advantage over BNC.
Also consider the fact that BNC version test result includes SMA-BNC interseries connector.
Leo
 
The following users thanked this post: edavid

Offline Howardlong

  • Super Contributor
  • ***
  • Posts: 4417
  • Country: gb
Re: Yet another fast edge pulse generator
« Reply #229 on: October 21, 2017, 07:14:50 am »
I realise it might be a bit niche, but a native SMA or 3.5mm version might perform even better!
It would need total redesign to show appreciable improvement.
I have tested SMA version today and apart from subtle changes it did not have much advantage over BNC.
Also consider the fact that BNC version test result includes SMA-BNC interseries connector.
Leo

Understood, but... you’re assuming I am in the ownership of a kickass bnc-f to sma-m interseries adapter. I have a couple decent amphenol ones going the other way. A decent interseries adapter would cost significantly more than your generator ;-)

I realise t’internet can obscure wry smiles, which is how I wrote my last message and write this one too: I know it’s not a simple part replacement, it’s a board respin and test, and there’s unlikely to be much of a market, but I live in hope, until I can find a decent reasonably priced interseries adapter of course!

In the meantime, thanks for your product, it’s certainly appreciated here.
 

Offline Howardlong

  • Super Contributor
  • ***
  • Posts: 4417
  • Country: gb
Re: Yet another fast edge pulse generator
« Reply #230 on: October 21, 2017, 07:20:07 am »
Hmmm, did you take your existing board and simply replace the BNC with an appropriately dimensioned SMA? I migt be interested in doing that mod, if it’s that simple and I can find the SMA male with the right mount. It might mean I’ll have to buy another pulse generator, of course.
 

Offline Leo Bodnar

  • Frequent Contributor
  • **
  • Posts: 564
  • Country: gb
Re: Yet another fast edge pulse generator
« Reply #231 on: October 21, 2017, 07:39:07 am »
Hmmm, did you take your existing board and simply replace the BNC with an appropriately dimensioned SMA? I migt be interested in doing that mod, if it’s that simple and I can find the SMA male with the right mount. It might mean I’ll have to buy another pulse generator, of course.
Howard, I can do this for you (or anyone else) if you want.  This is, perhaps, slightly ugly looking but mechanically and performance-wise very solid.  There are 0201 components near the central pin solder joint so if you are doing it yourself make sure you don't sweep them off.  You know your components are small when they fall down through the vias.
I can put male or female SMA and set it at 90 degrees, not skewed like below.  SMA female was quite expensive so I'd need to charge an extra £10 for this version.

In fact, you are welcome to this one that you see on the pictures and risetime plot. Photos are of the actual item. :D

Leo

Offline KE5FX

  • Frequent Contributor
  • **
  • Posts: 941
  • Country: us
    • KE5FX.COM
Re: Yet another fast edge pulse generator
« Reply #232 on: October 21, 2017, 07:40:31 am »
I have tested SMA version today and apart from subtle changes it did not have much advantage over BNC.
Also consider the fact that BNC version test result includes SMA-BNC interseries connector.
Leo

It's not that the performance of the BNC connector is unacceptable in itself, it's that the whole idea behind a fast pulser is to test fast hardware.  Having to use a BNC-to-SMA adapter with a fast DUT is certainly worse than having to use an SMA-to-BNC adapter with a slower DUT.
 

Offline Leo Bodnar

  • Frequent Contributor
  • **
  • Posts: 564
  • Country: gb
Re: Yet another fast edge pulse generator
« Reply #233 on: October 21, 2017, 07:46:39 am »
It's not that the performance of the BNC connector is unacceptable in itself, it's that the whole idea behind a fast pulser is to test fast hardware.  Having to use a BNC-to-SMA adapter with a fast DUT is certainly worse than having to use an SMA-to-BNC adapter with a slower DUT.
I accept your reasoning but I had problems with people not being able to find suitable USB cable locally.
Looks like I'd have to make and stock SMA version as well at some point.
Leo

Offline KE5FX

  • Frequent Contributor
  • **
  • Posts: 941
  • Country: us
    • KE5FX.COM
Re: Yet another fast edge pulse generator
« Reply #234 on: October 21, 2017, 08:18:19 am »
It's not that the performance of the BNC connector is unacceptable in itself, it's that the whole idea behind a fast pulser is to test fast hardware.  Having to use a BNC-to-SMA adapter with a fast DUT is certainly worse than having to use an SMA-to-BNC adapter with a slower DUT.
I accept your reasoning but I had problems with people not being able to find suitable USB cable locally.
Looks like I'd have to make and stock SMA version as well at some point.
Leo

Would it make sense to go with SMA on the next spin, and sell an optional BNC adapter to go with it?
 

Offline Howardlong

  • Super Contributor
  • ***
  • Posts: 4417
  • Country: gb
Re: Yet another fast edge pulse generator
« Reply #235 on: October 21, 2017, 09:37:44 am »
Hmmm, did you take your existing board and simply replace the BNC with an appropriately dimensioned SMA? I migt be interested in doing that mod, if it’s that simple and I can find the SMA male with the right mount. It might mean I’ll have to buy another pulse generator, of course.
Howard, I can do this for you (or anyone else) if you want.  This is, perhaps, slightly ugly looking but mechanically and performance-wise very solid.  There are 0201 components near the central pin solder joint so if you are doing it yourself make sure you don't sweep them off.  You know your components are small when they fall down through the vias.
I can put male or female SMA and set it at 90 degrees, not skewed like below.  SMA female was quite expensive so I'd need to charge an extra £10 for this version.

In fact, you are welcome to this one that you see on the pictures and risetime plot. Photos are of the actual item. :D

Leo

You’re on: PM me the total inc P&P with your Paypal details.

FWIW, 0201 not a problem here. Sometimes I go down to 01005 if I have to. 008004 not yet encountered, probably just a matter of time though the way things are going. Meh, 0201 passives going down vias, I had a 3x2 ball CSP do that on me recently. Losing a $0.001 passive is one thing, a $3 chip feels much less of a write off, especially if you’re down to your last 2 or 3 contingency parts on a prototype.
 

Offline borjam

  • Supporter
  • ****
  • Posts: 638
  • Country: es
  • EA2EKH
Re: Yet another fast edge pulse generator
« Reply #236 on: October 23, 2017, 06:34:15 pm »
I ordered one last week, should arrive today :)

One suggestion: could you please share the protocol specs to configure it? A Windows program is very inconvenient for someone not using Windows. It should be very easy to implement in Python, at least for simple command-line usage.

 

Offline HighVoltage

  • Super Contributor
  • ***
  • Posts: 3904
  • Country: de
Re: Yet another fast edge pulse generator
« Reply #237 on: October 23, 2017, 08:05:11 pm »
Looks like I'd have to make and stock SMA version as well at some point.
Leo

Leo,
If you ever release a SMA version, I am interested in getting a 3rd pulse generator from you.
Thanks!
 
There are 3 kinds of people in this world, those who can count and those who can not.
 

Online Berni

  • Super Contributor
  • ***
  • Posts: 1598
  • Country: si
Re: Yet another fast edge pulse generator
« Reply #238 on: October 23, 2017, 10:12:19 pm »
Seeing that most people are using these to test scopes i think a BNC is pretty welcome.

That being said i do tend to use SMA for everything and since test equipment usually does not have SMA i have a bunch of SMA to BNC and to N cables.

Is it possible to give it a dual footprint that takes both? Then have the BNC one be the standard version while the special version having no connector soldered and provide one SMA in the kit (Some other non SMA connectors also fit)

That being said is this thing actually useful for RF stuff? Like maybe being a comb generator or something. I never tried mine on a spectrum analyzer.
 

Offline borjam

  • Supporter
  • ****
  • Posts: 638
  • Country: es
  • EA2EKH
Re: Yet another fast edge pulse generator
« Reply #239 on: October 23, 2017, 10:17:48 pm »
That being said is this thing actually useful for RF stuff? Like maybe being a comb generator or something. I never tried mine on a spectrum analyzer.
As a TDR to examine coaxial cable runs?
 

Offline Leo Bodnar

  • Frequent Contributor
  • **
  • Posts: 564
  • Country: gb
Re: Yet another fast edge pulse generator
« Reply #240 on: October 23, 2017, 11:06:47 pm »
That being said is this thing actually useful for RF stuff? Like maybe being a comb generator or something. I never tried mine on a spectrum analyzer.
I have tried it on 8595E just now.
Green trace is SA noise floor.
Leo

Offline Leo Bodnar

  • Frequent Contributor
  • **
  • Posts: 564
  • Country: gb
Re: Yet another fast edge pulse generator
« Reply #241 on: October 23, 2017, 11:11:20 pm »
One suggestion: could you please share the protocol specs to configure it? A Windows program is very inconvenient for someone not using Windows. It should be very easy to implement in Python, at least for simple command-line usage.
I'll try putting something together. You can only adjust output level and inversion, so it's not very exciting.
Leo

Offline borjam

  • Supporter
  • ****
  • Posts: 638
  • Country: es
  • EA2EKH
Re: Yet another fast edge pulse generator
« Reply #242 on: October 23, 2017, 11:54:19 pm »
One suggestion: could you please share the protocol specs to configure it? A Windows program is very inconvenient for someone not using Windows. It should be very easy to implement in Python, at least for simple command-line usage.
I'll try putting something together. You can only adjust output level and inversion, so it's not very exciting.
Thanks! If you have a simple description I can try to implement it in Python myself. Needless to say I'll share the program.
 

Offline HighVoltage

  • Super Contributor
  • ***
  • Posts: 3904
  • Country: de
Re: Yet another fast edge pulse generator
« Reply #243 on: October 24, 2017, 12:13:06 am »
I have tried it on 8595E just now.
Green trace is SA noise floor.
Leo

How did you capture that trace from the HP 8595E so clearly?
There are 3 kinds of people in this world, those who can count and those who can not.
 

Offline Leo Bodnar

  • Frequent Contributor
  • **
  • Posts: 564
  • Country: gb
Re: Yet another fast edge pulse generator
« Reply #244 on: October 24, 2017, 12:22:01 am »
How did you capture that trace from the HP 8595E so clearly?
Thanks to KE5FX and his software - I did not have a proper chance to say how good and useful his stuff is! 
http://www.ke5fx.com/gpib/readme.htm

I'd wish for the font to line-up slightly better but I believe it is vectorised and compiled into the code. 
I have spent exactly 30 seconds on this issue because it is not a problem at all, just nit-picking.

Leo

Offline Leo Bodnar

  • Frequent Contributor
  • **
  • Posts: 564
  • Country: gb
Re: Yet another fast edge pulse generator
« Reply #245 on: October 24, 2017, 01:15:47 am »
Here is measured spectrum (blue) against theoretical spectrum of ideal square wave (red) - only odd harmonics are shown for clarity.
My SA has not been calibrated for ages but it does not look too bad.
Leo

Offline KE5FX

  • Frequent Contributor
  • **
  • Posts: 941
  • Country: us
    • KE5FX.COM
Re: Yet another fast edge pulse generator
« Reply #246 on: October 24, 2017, 05:22:28 am »
How did you capture that trace from the HP 8595E so clearly?
Thanks to KE5FX and his software - I did not have a proper chance to say how good and useful his stuff is! 
http://www.ke5fx.com/gpib/readme.htm

I'd wish for the font to line-up slightly better but I believe it is vectorised and compiled into the code. 
I have spent exactly 30 seconds on this issue because it is not a problem at all, just nit-picking.

Leo

You're welcome -- credit goes to texaspyro for his work on the renderer.  :-+  You can try displaying the plot with 7470_legacy.exe to use the old fixed-width font, but for everything that looks better, something else will tend to look worse.  HP-GL is hard to get right.
 

Offline borjam

  • Supporter
  • ****
  • Posts: 638
  • Country: es
  • EA2EKH
Re: Yet another fast edge pulse generator
« Reply #247 on: October 24, 2017, 06:07:17 pm »
Received yesterday, nice piece of kit!

I didn't have much time but I tried it on a Siglent SDS1202X-E and a "grown up" Rigol DS1074Z (using a T BNC adapter and a SMA 50 ohm terminator from the miniVNA Tiny calibration kit) and it works very well. I even did a quick and dirty TDR with a piece of coax.

Hoping to have more time this week, I'll post the screenshots.
 

Offline texaspyro

  • Frequent Contributor
  • **
  • Posts: 940
Re: Yet another fast edge pulse generator
« Reply #248 on: October 25, 2017, 12:19:12 pm »
How did you capture that trace from the HP 8595E so clearly?
Thanks to KE5FX and his software - I did not have a proper chance to say how good and useful his stuff is! 
http://www.ke5fx.com/gpib/readme.htm

I'd wish for the font to line-up slightly better but I believe it is vectorised and compiled into the code. 
I have spent exactly 30 seconds on this issue because it is not a problem at all, just nit-picking.

Leo

You're welcome -- credit goes to texaspyro for his work on the renderer.  :-+  You can try displaying the plot with 7470_legacy.exe to use the old fixed-width font, but for everything that looks better, something else will tend to look worse.  HP-GL is hard to get right.

Yep,  HP-GL rendering is a royal pain... there is basically no way to "get it right".   There are a LOT of interpretations of what HP-GL should do and it seems that everything that spews HP-GL somewhere does it wrong / different.   It was a lot of work getting the HP-GL2 renderer to handle all the example files in the gpibkit install.   You tweak it for one oddball, fubar'd instrument and it borks another one.  Anyway, 7470.exe has one of the most capable HP-GL renderers out there... at least for instrument dumps   ;)   The CERN viewer is also very good:  http://service-hpglview.web.cern.ch/service-hpglview/hpglviewer.html

I originally wrote the HP-GL renderer to use with my Atmel 2561 based GPIB controller that emulates a Prologix serial GPIB interface.  It was done as sort of a joke, but turned out to be rather useful.  It could display instrument screen dumps (HP-GL or PCL) on a 160x80 monochrome LCD touchscreen.  The fonts used are vector fonts that were generated from a VGA dot matrix font (and are the same fonts used in Lady Heather and my gcode processor program). 

 

Offline HighVoltage

  • Super Contributor
  • ***
  • Posts: 3904
  • Country: de
Re: Yet another fast edge pulse generator
« Reply #249 on: October 25, 2017, 08:28:34 pm »
Hello KE5FX and texaspyro
Many years ago, I tried to find a software to collect a screen shot from my old HP spectrum analyzer, until I gave up. Now I am surprise to hear that there is something.
Thank you so much !

I am traveling right now, but I will test this on the weekend, when I am back.
You should start a separate thread on this, I think lots of people would be interested.

In the olden days, when I had a HP plotter, I was always curious why the plotting sequence was sometimes very odd. And every plot that was made, was different in sequence. May be that was also a problem in programming a capture software for HP/GL?

There are 3 kinds of people in this world, those who can count and those who can not.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf