Paul:
There was a paper in J. Magn. Res. A 112, 250, 1995 by
Byrd and DiGennaro that covered the subject and I have been
looking into it to see whether we should package this into a kit
and sell it.
Here are some of the things I have found:
1. You do not need an expensive scope. You can demodulate
(rectify) the RF and and load the diode with a low
resistance. Most diode detectors have a 1 nF bypass cap. so
that a 100 Ohm load will give you a .1 us time constant.
Both Pasternak and hp have detectors for 95 to 135$ ea.
2. Bird has an adjustable sampler that samples the power going
to the probe. It can be set around 40 to 50 db, which
appears correct for the 100 mW the detectors can accept.
Price is 138$.
3 Since the output of the loaded diode detectors is low (20 to
500 mV), Byrd adds buffers in the switchbox. They are not
essential.
This combined with a scope of 20 to 100 MHz bandwidth will give
you a resolution of < 1us on the display. More details on
request.
Anyone interested in buying this as a kit?
Cheers Rolf
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Rolf Tschudin _ Tel. 1 301 496 2692
Bldg.5, Rm.B2-29 _| |_ Fax. 1 301 496 0825
National Institutes of Health |_ _|
Bethesda, MD 20892-0505 |_| E-mail: tschudin@nih.gov
USA CompuServe: 71543,751
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Any similarity between the opinion expressed above and that of my
employer is strictly coincidental.
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