Re: DIY TD Pulser

Jeff Davis

Not sure what exactly you have two of... 😊

I've posted some test results from two samples of the build I did following the notes from Sergey Kubushyn. The test was conducted over the noon hour on an 8 GHz digital Tektronix scope at work - didn't catch the exact model number.

I posted captures of the rise time photos under "DIY TD Pulser" in the Photos section. Got 159 pS on the first build. Was a little more careful with the output construction on the second and got down to 119 pS with it.


From: <> on behalf of Chuck Harris [TekScopes] <>
Sent: Monday, November 13, 2017 6:46 PM
Subject: Re: [TekScopes] Re: DIY TD Pulser

I have two of them. One has a bad TD, the other works, but
is easily 10 times slower than the spec's say it should be.

I had heard that when tektronix made them they had no real
way of measuring the pulse risetime, so they guessed.

-Chuck Harris

David [TekScopes] wrote:
Why can't you use the random sampling capability on the 7T11? Then at
least no delay line should be required. A power divider might still
be desirable to separate the sampling kickout from the trigger.

Tektronix had a slightly more complex tunnel diode pulse generator
which generated a pretrigger:


It would be interesting to see the inside to see how it was

On Mon, 13 Nov 2017 23:53:05 +0000, you wrote:

Hey Joseph,

I built one of those, and the complexity/value is not in the circuit. It's
mostly in the characterization of the behavior of the physical construction
of the circuit. Mine has a rise time of ~200ps, as determined by my TDS
784D and some maths. Plenty good to calibrate the transient response of my
485 and 2467, though I do worry about the pre-shoot and overshoot I see on
the TDS.
I'll need to look closer one day, now that I have a 7834, 7S11/7T11 - just
need a decent power splitter and a delay line, and a few more little things


Posted by: David <>


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