General Form:

tf output_node input_source

The tf command performs a transfer function analysis, returning:

• the transfer function (output/input),
• output resistance,
• and input resistance

between the given output node and the given input source. The analysis assumes a small-signal DC (slowly varying) input. The following example file

Example input file:

* Tf test circuit
vs    1    0    dc 5
r1    1    2    100
r2    2    3    50
r3    3    0    150
r4    2    0    200

.control
tf v(3,5) vs
print all
.endc

.end

will yield the following output:

transfer_function = 3.750000e-001

output_impedance_at_v(3,5) = 6.662500e+001

vs#input_impedance = 2.000000e+002