User Guide

Monte Carlo analysis
301
6 To display current through the Meter voltage source,
do the following:
a From Capture’s PSpice menu, point to markers
and choose Current into Pin.
b Place a current probe on the left-hand pin of the
Meter source.
7 Switch to the Probe window to see the family of curves
for I(Meter) as a function of P.
Note
For more on analyzing Monte Carlo results in PSpice, see the next
section on Monte Carlo histograms.
Monte Carlo Histograms
You can display data derived from Monte Carlo
waveform families as histograms. This is part of the
performance analysis feature.
In this example, you simulate a fourth-order Chebyshev
active filter, running a series of 100 AC analyses while
randomly varying resistor and capacitor values for each
run. Then, having defined performance analysis goal
functions for bandwidth and center frequency, you
observe the statistical distribution of these quantities for
the 100 runs.
Chebyshev filter example
The Chebyshev filter is designed to have a 10 kHz center
frequency and a 1.5 kHz bandwidth. The schematic page
for the filter is shown in Figure 81. The stimulus
specifications for V1, V2, and V3 are:
V1: DC=-15
V2: DC=+15
V3: AC=1
The parts are rounded to the nearest available 1% resistor
and 5% capacitor value. In this example, note how the
Anot
h
er way to view t
h
e
f
ami
l
y o
f
curves
without using schematic markers is as
follows:
1 From PSpice’s Trace menu, choose Add
Trace.
2 In the Simulation Output Variables list,
double-click I(Meter).
Monte Car
l
o ana
l
ysis is
f
requent
l
y use
d
to
predict yields on production runs of a
circuit.
For more in
f
ormation a
b
out per
f
ormance
analysis, see RLC filter example
on
page 11-274.
Pspug.book Page 301 Wednesday, November 11, 1998 1:14 PM