In Reply to: SHF Pulse generator posted by tom on 01/31/02 at 12:58 PM:
Here are a few pointers which might be helpful:
1) In the Linear Technology '1997 Linear Applications Handbook', AN61, Jim Williams described a triggered 250pS rise time pulse generator, which uses a transistor under controlled avalanche breakdown conditions.
2) Zetex make transistors specifically for operation in avalanche breakdown mode, the ZTX413 and ZTX415, see www.zetex.com. They also have application notes describing pulse generators, AN8 and DN24, which include references to further material.
3) The avalanche circuits mentioned above might not be fast enough for your application. There is a book by T. H. O'Dell (called 'Circuits for Electronic Instrumentation' or something like that) in which he describes how to make a fast sampling gate (part of a sampling oscilloscope). The sampling gate was driven by a pulse generator using a step recovery diode. This at least might be useful background reading.
Sounds like a very interesting project. I wish you all success.