> > The NLB-300 and NBB-300 series MMICs from RFMD work very at up to 13GHz > or so, certainly far better than a Mini-circuits ERA- whose gain will > start to roll off at higher frequencies. Designing a broadband gain > stage to work up to 12GHz+ may not be as easy as it seems. However it > is made somewhat easier by the use of broadband chokes from the likes of > Mini-Circuits, wideband inductors from Coilcraft and broadband > capacitors from ATC - to name but three - there may be others as well. > > The 4-stage amplifier used by HP not only increases the signal level, it > increases the slew rate (V/uSec) at lower frequencies. It's not just > about signal level, it's about getting fast edges. The Hittite HMC363 > /8 is a great IC, using static flip-flops, and will work all the way > down to DC - IF the edges are fast enough. Ironically it may be the > case that the lower frequency limit presents more of a challenge than > the higher frequency limit.
True. The Hittite parts can be used all the way down to DC, if the edges are fast enough. :) The last time I wanted to build a prescaler capable of DC operation, I ended up using a tunnel diode to speed up the edges of low-frequency input signals. I used some crude LC filtering to bypass the TD for faster signals, routing them directly to the prescaler chip. The circuit worked well enough, but it was pretty twitchy. -- john, KE5FX _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.