User Guide

Control system parts
169
Example one
Suppose you want to set an output voltage on net 4 to 5
volts times the square root of the voltage between nets 3
and 2. You could use an ABM2 part (which takes two
inputs and provides a voltage output) to define a part like
the one shown in Figure 43.
In this example of an ABM device, the output voltage is set
to 5 volts times the square root of the voltage between
net 3 and net 2. The property settings for this part are as
follows:
EXP1 = 5V *
EXP2 = SQRT(V(%IN2,%IN1))
This will produce a PSpice netlist declaration like this:
ESQROOT 4 0 VALUE = {5V*SQRT(V(3,2))}
Example two
GPSK is an oscillator for a PSK (Phase Shift Keyed)
modulator. Current is pumped from net 11 through the
source to net 6. Its value is a sine wave with an amplitude
of 15 mA and a frequency of 10 kHz. The voltage at net 3
can shift the phase of GPSK by 1 radian/volt. Note the use
of the TIME parameter in the EXP2 expression. This is the
PSpice internal sweep variable used in transient analyses.
For any analysis other than transient, TIME = 0. This could
be represented with an ABM1/I part (single input, current
output) like the one shown in Figure 44.
This part is characterized by the following properties:
EXP1 = 15ma * SIN(
EXP2 = 6.28*10kHz*TIME
EXP3 = + V(%IN))
This produces a PSpice netlist declaration like this:
GPSK 11 6 VALUE = {15MA*SIN(6.28*10kHz*TIME+V(3))}
Figure 43 ABM expression part
example one.
Figure 44 ABM expression part
example two.
Pspug.book Page 169 Wednesday, November 11, 1998 1:14 PM