In this analysis (actual GFT.SCP file), we use a behavioral multiplexer within a subcircuit named
Xgft to reconfigure the null parameters for each of the 13 AC simulations.
To make the script work in a general sense, it is necessary for the
user to ALWAYS name the GFT model Xgft. There are 16 GFT models to choose
from. Look in GFT templates to see how
to match the model with the appropriate template. You can find a drawing
example in BJTAmplifier.dwg.
The variations account for different methods of signal injection and
input/output signal variation for voltage gain, current gain, transadmittance
and transimpedance. The GFT template is used to get an accurate measure
of a control system characteristic equations, including "the"
loop gain and closed loop gain even when the loop cut or injection point
experiences significant loading. After running the simulation, you can
plot the various control system parameters using the IntuScope calulator\GFT
menu. The following examples are available only with the full ICAP/4
versions, they do not ship with the demo:
Other simulation templates for the GFT include GFTE,
GFTEE, GFTJ, GFTJJ,
GFTS and GFTTIME