Am 25.11.2014 um 20:34 schrieb Charles Steinmetz:
A couple of people were asking about NIST isolation amplifiers
recently. I'm attaching circuit diagrams of the 5-10 MHz amp from
1997 and the 1-200 MHz amp from 1990. I think Bruce has the papers
linked at his ko4bb.com pages.
I have built _this_ version of the NIST preamp 6 or seven years ago. It
is quite ok and feeds the
signal generators, counters, SAs and VNA in my lab without issues.
There is >1 successor that
corrects the awful S11 and has no output transformer but it still awaits
characterisation. Maybe
over the holiday season to come.
Noise on the base voltage string is attenuated by transistor beta in the
cascode, so there is not too
much to gain here. The next 2 versions use even more current to support
13 dBm without transformer,
they run pretty hot ( 2 BFG31 chains/channel).
< http://www.hoffmann-hochfrequenz.de/downloads/downloads.html >
regards, Gerhard
_______________________________________________
time-nuts mailing list -- [email protected]
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
