On Sat, 21 Feb 2004 12:28:11 +0000, Paul Burridge
wrote:

On Sat, 21 Feb 2004 03:20:07 -0800, Roy Lewallen
wrote:

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?

What's a doubler based on the good old 1N4148 good for, top end
frequency-wise?

made some experiments 10-15 years ago with doublers to 144Mc/s, and
they probably would work on at least 200Mc. Best experience with a
BFR90 amplifier following the 'rectifier', see
http://home.online.no/~la8ak/c13.htm
It was important with certain dc load following the diodes and some
bias current

Another interesting multiplier used for 100kc calibrator - on vhf -
described in UKW Berichte uses quad nand schmidt trigger, where the
input signal is splitted - one part to a nand input and the other to
3x nand gates connected as inverters and connected to the second input
of the nand-gate such that the truth table said constant logic high
output, but a very thin spike occured because of the transition time
delay

73
JM
----
Jan-Martin, LA8AK, N-4623 Kristiansand
http://home.online.no/~la8ak/