User Guide

Chapter 9 AC analyses
246
About noise units
Example
You can run a noise analysis on the circuit shown in
Figure 60 on page 9-237.
To run a noise analysis on the example:
In Capture, open the EXAMPLE.DSN circuit provided
with your OrCAD programs in the
ORCAD\CAPTURE\SAMPLES
subdirectory.
1 From the PSpice menu, choose New Simulation
Profile or Edit Simulation Settings. (If this is a new
simulation, enter the name of the profile and click
OK.)
The Simulation Settings dialog box appears.
2 Choose AC Sweep/Noise in the Analysis type list box.
3 Under Options, select General Settings if it is not
already enabled.
4 Enable the Noise Analysis check box.
5 Enter the following parameters for the noise analysis:
These settings mean that PSpice will calculate noise
contributions and total output noise at net OUT2 and
equivalent input noise from V1.
Table 9
This type of noise output variable... Is reported in these units...
Device contribution of the form
N
xxx
Total input or output noise of the
form V(ONOISE) or V(INOISE)
Output Voltage V(OUT2)
I/V Source V1
Interval 30
volts()
2
Hz()⁄
volts()Hz()⁄
For a
d
escription o
f
t
h
e Interva
l
parameter,
see page 9-244
.
Pspug.book Page 246 Wednesday, November 11, 1998 1:14 PM