How to generate a width of 500 picosecond pulse?

How to generate a width of 500 picosecond pulse?

 

Use a step recovery diode.

 

What's the input, and what sort of load do you want to drive?

John

 

Two inches of coax with a short at one end. Drive with a fast edge,
e.g. from a step recovery diode.

Cheers,

Phil Hobbs

 

3"

John

 

John Larkin wrote...

2"

 

Nah, start with 1 foot of coax per nanosecond. Then keep trimming it
down until you get what you need with your load.

Al

 

(pssst: The speed of light in coax is about 2/3 C or about 7.8 in/ns)

 

Hello Al,

But be careful and mind what's in the direction where the coax snippet
flies. I have seen a guy do exactly that job with this stiff mil-spec
coax. One piece flew right through a vent hole into a scope. Bzzzt ...
poof. About $2000 worth of damage according to the repair invoice.

Regards, Joerg

 

Thougth the speed of light was metric these days?


martin

 

Why do you think they call Paris "the city of light"?


John

 

Cheaper than putting out an eye. :0

 

Hello Mike,

True. That's why I wear goggles/glasses when doing such work. Same when
I get a clients prototype and there are tantalums on it.

Regards, Joerg

 

I gave that as an answer in a test once, long ago and failed. The "correct
answer" was a one shot made with 2N2222's operating at <1.0mA currents.
Who knew!
Harry

 

Sure, but without a scope you're blind too.

 

See Linear Technology www.linear.com Application Note 47
'High Speed Amplifier Techniques' (page 93), for a discussion and
circuit using one of the techniques to generate less than 1ns pulses.

Linear Technology AN47, by Jim Williams, is a very good paper that
discusses in detail the precautions and pitfalls required when working
with very fast pulses and pulse edges. It contains lots of information
that details design, bread boarding and measurement techniques,
complimented by many circuits and scope trace photos.

Gerhard van den Berg

 

See Linear Technology www.linear.com Application Note 47
'High Speed Amplifier Techniques'(page 93), for a discussion
and circuit that employs one of the techniques to generate
less than 1ns pulses.

Linear Technology AN47 by Jim Williams is a very good paper
that discusses in detail all the precautions and pitfalls of
working with very fast pulses and pulse edges. It contains
extensive details on design, bread boarding and measurement
techniques, complimented by many circuits and scope trace photos.

Gerhard van den Berg

 

What about reflection doubling the length, and what about the fact
that waves travel slower in coax than in vacuum/air?
Methinks Mr. Hobbs was a lot closer to the correct length of coax.

 

Well, that takes care of the reflection, but...