Yet another fast edge pulse generator

[madao]

Hi

This is my frist posting.

 I has using  S-2 sampling head with specified tr of 75ps.  I have 2 faster sampling head  (S-4 with tr of 25 ps  )  but not BNC to SMA adapters.
 I'll repeating measuring with S-4 head, if i get  SMA-BNC Adapter.

Best regards
matt

[Converter]

From your devices want to hide in trenches 
I write about it with a sense of respect. They are as harsh and powerful as WWII tanks

[Insatman]

Matt...great vintage gear...I love old Tek stuff

[chickenHeadKnob]

Cheers, Tom. FB have hardware divisions.
Leo

In the news today:https://mashable.com/article/facebook-disbands-building-8/#gnOeGAa03qqm
Maybe the pulser they bought will show up on ebay.

The real value of Leo's tool for hobby dudes like myself is that it comes calibrated. I was unprepared for one thing though, the psychological after effects of seeing all the well endowed forum members posting their results and then comparing it to my measly LOL-RIG 300.

 Now I have no enjoyment left in life, food doesn't taste as good as it used to and young women/girls point at me and snicker when I am out in public.

[madao]

Yes,  leo's pulser is worth for money.


SMA-BNC is arrivied , i have trying with it and S-4 sampling head.  Only  a scrap, this adapter.

42ps , not bad, but  reponse is not clean and it isn't repeatable. I'll trying again with better adapter.

[JohnG]

While I like good, working vintage equipment, old oscilloscopes have never had much draw for me...

But, you have shown me the light!

[madao]

  Hewlett Packard an Tektronix has doing war with  sampling oscilloscope in 1960s.  HP sampling oscilloscope is  a bit faster than Tektronix, but has not one automated oscilloscope in offers.  Tektronix is pioneer of automated measuring in 1960s.   Very little & special market, this S-3100 family is offered into  1980s, but not many sells (below 2000 produced units ). (of coruse, small & special market )
One old men is always telling with glowed eye about biggest (S-3150) from  S-3100 family.  It is running with PDP-8.

http://w140.com/tekwiki/images/a/aa/S-3100_Series_Brochure.pdf

This  oscilloscope and  digital unit is  heart-piece of  this system.

[rhb]

Thanks for sharing that link.  That is really cool.  I bet it cost a fortune.

[madao]

no problems.  TekWiki (w140.com) is interressing site.  Fortune, yes,  old men talks about million franc (swiss, 1980s) for this big automated machine.

I think,i am leading monologue :-)

Telegärtner* Adapter ist arrivied, it is much better than  china-stuff.
faster risetime and smoother reponse. I have using  torque wrench from Radiall for SMA for fixing adapter at S-4 sampling head.


* a german company for connector, also good stuff.

[bitbanger]

Any EEVBlog member discount for those who don't have FB/NASA-level deep pockets? 

[Leo Bodnar]

The price already has any possible discounts in.  NASA is just paying EEVBlog price, not the other way round.
Leo

Any EEVBlog member discount for those who don't have FB/NASA-level deep pockets? 

[bitbanger]

The price already has any possible discounts in.  NASA is just paying EEVBlog price, not the other way round.
Leo

Fair enough - I think the price is totally worth the effort that obviously went into this. However in the words of my long gone father, "never hurts to ask".

Cheers!

[MrW0lf]

Siglent SDS2352X-E + 50ps BNC pulser into native 50Ω

0.35 / 0.9ns ~= 389MHz

[HighVoltage]

 Shahriar of The Signal Path did a really nice review of Leo Bodnar's pulse generator in November, that I just came across.

[Berni]

This pulse generator also got into a video on HackADay:
https://youtu.be/STCGzanAyR0?t=630

[gammaburst]

Thanks Leo for the super-fast shipping!

Here are screenshots of the BNC PULSER into a Keysight MSOS804A scope, showing real-time and equivalent-time sampling modes. Fastest indicated transition is 53.2ps. This scope has a brickwall filter around 8.4 GHz.

[KrudyZ]

When you see the wiggles BEFORE the edge you know it's DSP voodoo in action...

[exe]

When you see the wiggles BEFORE the edge you know it's DSP voodoo in action...

You mean data before trigger? Some scope have continuous capture and digital trigger, they may show data before trigger... But this should be mentioned in spec . I know R&S have this.

[Gerhard_dk4xp]

That you can see the history before the trigger, that is old.
Even historic analog scopes had a delay line good for some 20 nsec.

But when the ringing starts before the edge that excites it, then there
must be something that can look into the future.

Or there is a prettyfier algorithm at work that massages the data
until fit for display.

I'd prefer causality.

Cheers, Gerhard

[tggzzz]

When you see the wiggles BEFORE the edge you know it's DSP voodoo in action...

It isn't voodoo. It is the Gibbs phenomenon.

I was taught about it in school (UK school, i.e. before university). Draw a graph of sin(x)+¹/₃sin(3x)+¹/₅sin(5x) and you will see it too.

The Gibbs phenomenon can be seen in both analogue and digital signal processing.

[Leo Bodnar]

It's not that ideal brick-wall filter looks into the future. It just takes infinitely long time to accumulate [and process] data.
Leo

That you can see the history before the trigger, that is old.

[Berni]

Yep even analog filters can give the "pre wiggle"

Its not seeing into the future, instead the filter is delaying the waveform so much. When the wiggles start the filter has already got the edge on its input, but it takes a while for the edge to make it trough the filter magic and appear on the output. Filters have to cause these delays in order to observe what the waveform is doing around the point.

But yeah most brick wall filters are implemented digitally because its easier to do these days.

[Gerhard_dk4xp]

Of course, it does on the screen. At t = -200 ps, we cannot yet be sure that the rising edge
will come at all, there still could be a dropping clock enable, but the trace is already
shivering in anticipation of the things to happen. That is simply wrong. We do not want
a brick wall filter, it is only there  so that marketing can advertize more -3dB bandwidth than is really
usable. When I see that step response: Is that pre-edge ringing the ground bounce of my driver
chip, or capacitive feedtrough trough the driver, or is it just an artefact?

If it is an artefact, is the ringing after the edge also an artefact, or do I have a little resonator
somewhere? It looks so identical to the time when we could not know if the pulse would fire at all.

If you read the book of Hollister on wideband amplifier design or that of Staric, you can see
what amount of work they used to put at Tektronix into their Y amplifiers, just to get a clean
step response. That has been replaced by marketing in the mean time.

Is there any pre-ringing in the screen dumps of that old 68030-based sampling scope?
Which scope should I trust when I tune the bias tee?

<   https://www.flickr.com/photos/137684711@N07/46284720054/in/album-72157706443876665/    >

(54751A 20 GHz plug in & 54754A 18 GHz differential TDR, and the pics left/right).
I have made these pictures this week for a discussion of bias tees on usenet sci.electronics.design.

regards,
Gerhard

[exe]

So, there is actually no pre-ringing, it's just an artifact of interpolation?

[Converter]

So, there is actually no pre-ringing, it's just an artifact of interpolation?

That says it all:
https://en.wikipedia.org/wiki/Gibbs_phenomenon