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Subject: Re: SHF Pulse generator
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Date: 01/31/02 at 5:50 PM
Posted by: tom
In Reply to: Re: SHF Pulse generator posted by Russ Kincaid on 01/31/02 at 4:05 PM:
Russ, I appreciate your help. Theres not to many people that I know of who have even heard of a tunnel diode. I was thinking of using a step recovery diode because from what I understand they seem to be more easily obtianed then tunnel diodes. This whole thing is basically a time domain reflectometer that will work acuratley on short distances(accuracy to +/- 1mm). The pulse is to be transmitted through a 50ohm coaxial probe. The probe length will vary from 3 to 70ft. I need to measure the time between pulse transmition and reception of the reflection back to the same point. The pulse (actually pulses) need to be transmitted at certian intervals so the recieve signal can be "beat down" to a measureable time increment. This time increment can then be converted into distance. I was hopeing, probably in vain, for a chip device with a very short output transition time from low to high. Somewhere in the pico second range. Whats important as far as the pulse is concerned is the rise time. Something like a schmitt trigger would be great if there were transistors that could handle the frequency. A low level signal would be fine. A 5V signal would probably be overkill.
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