rise time of pulses of a HP8133A by Tek 11403, TDS 820 and Tek 11801

[Physikfan]

Hello oscilloscope friends

I plan to show the rise times of a HP8133A by Tek 11403 (11A72, 1GHz), TDS 820 (6GHz) and Tek 11801 (with SD-20, 20GHz).

Why this?

The HP 8133A can provide pulses between 33 MHz and 3 GHz frequency,
with up to 3.0 Vp-p amplitude and transition times of <60 ps (20% -80%).
It is at least interesting to me which oscilloscope can show the form of pulses, and how close to reality.

I hope that these experiments are not considered absolutely trivial and can be of interest.

I am curious about your comments, tomorrow morning I will start

regards

Physikfan

[edavid]

Don't we use 10%-90% here?

How will you interconnect the HP8133A and the scopes?  (I would suggest a short hardline.)

[Physikfan]

Hi edavid

HP specification for 10% up to 90% amplitude (rise time) is <100 ps.

I will not use a rigid cable, because I want to use the same cable for all three oscilloscopes, for the 11402 I will use an adapter SMA to BNC.

But I will try to find out a possible difference between a flexible and a semi rigid connection.

[PartialDischarge]

You should visit "show us your square wave" !!

https://www.eevblog.com/forum/testgear/show-us-your-square-wave/

[Physikfan]

Hi mastertech

Thanks for giving me the hint to visit "show us your square wave".
I have learned a lot.
Unfortunately most of the pictures were not readable for me:

"please update your account to enable 3rd party hosting
for important info, please go to
www.photobucket.com/P500"

Regards

Physikfan

[Physikfan]

These are the first results:

Square wave of the HP8133A with the Tektronix sampling oscilloscope 11801C, x-axis 50ps / div, y-axis 200mV / div, with head SD26, rise time 17.5 ps, bandwidth 20 GHz.



200 ps wide pulse of the HP8133A with the Tektronix Sampling oscilloscope 11801C,  x-axis 50ps / div, y-axis 200mV / div, with head SD26, rise time 17.5 ps, bandwidth 20 GHz.



The displayed rise time is about 50 ps in both cases.

[David Hess]

Don't we use 10%-90% here?

Sometimes you have to use 20%-80% because 10%-90% is unrealistic when the cable suffers from dribble up.

[Physikfan]

Here are the results measured by a TDS820, 6 GHz oscilloscope with 44 ps rise time:

Square wave of the HP8133A,  x-axis 50ps/div, y-axis 200mV/div:



200 ps wide pulse of the HP8133A,  x-axis 50ps/div, y-axis 200mV/div:



The displayed rise time is about 65 ps in both cases.

[Leo Bodnar]

The displayed rise time is about 50 ps in both cases.

Why don't you use internal 11801 risetime calculation?
If you select the risetime measurement then tap on "Rise" rectangle then you can adjust Proximal and Distal values to 20% and 80% using the knobs - like below.
Let the machine do it for you.  Tek engineers designed 11800 series 30 years ago so it's time we finally figured out how to use it.
Cheers
Leo