User Guide

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s You Need to Know
Parameter
A parameter defines a property of the design for
which the PSpice Optimizer attempts to determine the best value
within specified limits. A parameter can:
• Represent component values (such as resistance, R, for
a resistor).
• Represent other component attribute values (such as
slider settings in a potentiometer).
• Participate in expressions used to define component
values or other component attribute values.
The PSpice Optimizer can optimize designs with up to eight
variable parameters.
Example: A potentiometer symbol in a schematic uses the SET
attribute to represent the slider position. You can assign a
parameterized expression to this attribute to represent variable
slider positions between 1 and 0. During optimization, the
PSpice Optimizer varies the parameterized value of the SET
attribute.
Specification
A specification describes the ideal behavior
of a design in terms of goals and constraints.
Examples: For a given design, the gain shall be 20 dB ±1 dB; for
a given design, the 3 dB bandwidth shall be 1 kHz; for a given
design, the rise time must be less than 1 usec.
A design can have up to eight goals and constraints in any
combination, but there must always be at least one goal. You can
easily change a goal to a constraint and vice-versa.
The PSpice Optimizer accepts specifications in two formats:
internal and external.
Internal specifications
An internal specification is composed of goals and constraints
defined in terms of target values and ranges, which are entered
into the PSpice Optimizer through dialog boxes.
See Chapter 6,Tutorial:
Exploring Design Tradeoffs
(Active Filter) startin
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example
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parameterized slider
values.
For more information, see Goal
and
Constraint on page 1-8.