Tom Bruhns wrote:
. . .
. . . Seems like step
recovery diodes are not in as great favor as they once were, since
there are generally better ways to generate higher order harmonics.
. . .

Getting a bit off-topic here, but as of a few years ago, we were using
step recovery diodes to generate the step in high speed TDR systems, and
to generate the strobe for the sampling gate in high speed sampling
scopes. Rise times were on the order of 7 - 15 ps (bandwidth up to 50
GHz or so), limited primarily by circuitry external to the diodes. SRDs
replaced tunnel diodes in earlier generations of instruments. I've been
out of touch with that class of instruments for a few years now -- do
you know if something has replaced the SRD for generating fast steps, or
just for harmonic generation?

Roy Lewallen, W7EL