are there any resources available on design of bidirectional amps on
the net?
i have read the few paragraphs in SSD and EMRFD. I am looking for some
better material.
In particular, I have the following questions:
1) consider that we have two broad-band amps based on a single npn
transistor with a Feedback resistor of Rf and emitter degeneration of
Re. consider, further, that we simply connect them back to back and
power one or the other, depending upon with direction you might want
to amplify. Now, what is the total feedback resistance? is it Rf or
Rf/2 (the Rf is between the inputs and the outputs and they are cross
coupled, paralleling Rf resistors.
2) Suppose that the output load of a bidirectional amplifier is RL and
resistor from collector to Vcc is Rc. Now, does Rc have to same as RL?
I guess this is required for best power transfer. But, when the
amplifier is amplifying in the opposite direction, then the amp input
is paralleled by the Rc. Thus, won't the input impedance of the amp
drop by two?
3) Will substituting a pi type attentuator for the load and feeding
the input in the opposite direction through the same attenuator solve
the problem?

- farhan