The model provided for a 2-port S-parameter block is
restrictive in that the common port is hard-tied to
ground. A great increase in utility of this program will
result if this node could be connected in a more arbitrary
fashion. An example would be a resistive feedback
amplifier stage, where a resistor exists in series with the
transistor emitter, and resistive feedback is added from
the collector to the base as well. This feature would
also allow the user to model common-base or common-
collector amplifiers with devices specified by common-
emitter S parameters. This capability has been
standard in linear analysis simulators for quite some
time, including the old "Touchstone" simulator that
sparked interest in this project to begin with.
Understood is the fact that this increases the
complexity of the simulation.