Hi I’ve built that one as well. It’s a bit easier with +/- supplies.
It has the same “you need a good layout” issues as any of the other versions. It’s got a bit higher input impedance than the others so it’s better choice for > 4 outputs. Bob > On Nov 25, 2014, at 6:53 PM, Gerhard Hoffmann <[email protected]> wrote: > > 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. _______________________________________________ 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.
