EMRFD Message Archive 1692
Message Date From Subject 1692 2008-06-05 07:43:27 bkopski EMRFD FBA - A VARIANT Hi All -
Continuing the wide band amplifier pursuit, I have configured a
variation of Chapter 2 amplifiers as shown in the Files section.
As is obvious, the big difference here is the incorporation of a
follower between the input and the amplifier transistor. But the
really big difference is in the resulting performance. Three .jpg's
in the Photo section show what I mean.
In all photos, the frequency sweep width is 200 mHz total. In
the "Gain" photo, the reference trace is that of the total test
system wherein (as before) the "in" and "out" test points are 6 dB
pads connected together. Thus, the sweeper, cables, QST power meter,
its output everything is in this reference trace. The trace
depicting the amplifier response is the result of inserting the
amplifier between the test ports (pad) and this is how the ~10 dB
gain is depicted over frequency. One can mentally subtract
the "reference" trace from the "gain" trace to imagine "flatness".
The "Track" photo is merely a manipulation (positioning) of the
reference and gain traces so that the amplifier in-to-out response
tracking is more clear.
The Return Loss photo shows reasonably good performance over
frequency although I must acknowledge that I'm not sure just how good
my EMRFD / SSD HB bridge is over this frequency range.