User`s guide

6
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30 Analo
g
Behavioral Modelin
g
Refer to the online MicroSim PSpice A/D Reference Manual for
detailed information.
Modelin
g
Mathematical or
Instantaneous Relationships
The instantaneous models (using VALUE and TABLE
extensions to PSpice A/D “E” and “G” devices in the symbol
templates) enforce a direct response to the input at each moment
in time. For example, the output might be equal to the square
root of the input at every point in time. Such a device has no
memory, or, a flat frequency response. These techniques can be
used to model both linear and nonlinear responses.
Note
For AC analysis, a nonlinear device is first
linearized around the bias point, and then the
linear equivalent is used.
EVALUE and GVALUE parts
The EVALUE and GVALUE parts allow an instantaneous
transfer function to be written as a mathematical expression in
standard notation. These parts take the input signal, perform the
function specified by the EXPR attribute on the signal, and
output the result on the output pins.
In controlled sources, EXPR may contain constants and
parameters as well as voltages, currents, or time. Voltages may
<ABM
keyword>
specifies the form of the transfer function
to be used, as one of:
VALUE arithmetic expression
TABLE lookup table
LAPLACE Laplace transform
FREQ frequency response table
CHEBYSHEV Chebyshev filter
characteristics
<ABM
function>
specifies the transfer function as a
formula or lookup table as required by
the specified <ABM keyword>