User Guide

Chapter 2 Simulation examples
46
To compare the last run to the first run
1 From the Trace menu, choose Add Trace to display the
Add Traces dialog box.
2 In the Trace Expression text box, type the following:
Vdb(Out)@1 Vdb(Out)@21
3 Click OK.
Note
The difference in gain is apparent. You can also plot the difference
of the waveforms for runs 21 and 1, then use the search commands
to find certain characteristics of the difference.
4 Plot the new trace by specifying a waveform
expression:
a From the Trace menu, choose Add Trace.
b In the Trace Expression text box, type the
following waveform expression:
Vdb(Out)@1-Vdb(OUT)@21
c Click OK.
5 Use the search commands to find the value of the
difference trace at its maximum and at a specific
frequency:
a From the Tools menu, point to Cursor and choose
Display.
b Right-click then left-click the trace part (triangle)
for Vdb(Out)@1 - Vdb(Out)@21. Make sure that
you left-click last to make cursor 1 the active
cursor.
c From the Trace menu, point to Cursor and choose
Max.
d From the Trace menu, point to Cursor and choose
Search Commands.
e In the Search Command text box, type the
following:
search forward x value (100)
f Select 2 as the Cursor to Move option.
press I
You can avoi
d
some o
f
t
h
e typing
f
or t
h
e
Trace Expression text box by selecting
V(OUT) twice in the trace list and inserting
text where appropriate in the resulting
Trace Expression.
press I
T
h
e searc
h
comman
d
te
ll
s PSpice to searc
h
for the point on the trace where the x-axis
value is 100.
Pspug.book Page 46 Wednesday, November 11, 1998 1:14 PM