The Signal Integrity Analyzer examines the probable distortion of high-speed
signals as they pass through traces on the PCB. The results of the analysis are
displayed in the Waveform Viewer. The purpose is to predict how a signal
deviates from its ideal (or intended) behavior in a real-world setting.
Steps
for Signal Integrity Analysis
Under normal working conditions, signals propagate
from some pins of the components in the circuit (technically called Driver
Nodes), through the interconnecting traces and into pins on the same or other
components (called
Receiver Nodes).
This analysis detects the degree of
distortion of the signal from its ideal behavior while it passes through the
trace and graphically presents the comparison result with the help of the
Waveform Viewer. .
1. Right click on the
PCB LAYOUT in the Project Explorer, select
Board
Analyzer. Select the
Electromagnetic Analyzer tab.
2. Right click
on the workspace and select the tool
Signal Integrity / Field Analyzer, and click on any of the trace,
which is to be analyzed.
3. Now select a net. A window pops up where you may set all the parameters for
simulation. To check the integrity of an electromagnetic signal while it passes
through this trace, go through the following steps.
4. All nets are displayed in the frame Available Nets. Select a net from the
list and click
.The segment nodes of the selected net get displayed in the frame. Right
click on any of the node and set it as driver node and another node as receiver
node.
5. The electrical properties of the trace will influence the signal as it passes
through it and this is shown in the respective columns. The Trace Segment
parameters of the driver node may be viewed by clicking on Show Trace
Segments.
6. Set the following parameters.
Max voltage to 5V
T L->H = 0
T H = 1us
T H-> L = 0
T L = 1us
7. Set TTL technology to the receiver nodes. Check the check box corresponding to Test Points. The
Test points allow displaying the output of the selected node in the waveform viewer. If no test point is selected then output waveform alone is displayed on the waveform viewer.
8. To execute simulation, Start time and End time of the simulation as well as the sampling time interval must be specified. This corresponds to the parameters Start time, Time limit and Time step. Enter 1n for Time Step and 2μs for Time limit.
9. Click on Calculate button. The Calculate button allows to calculate the maximum time limit and will update the text box Time limit. Here the time step is set to 1ns and Time limit to 2us.
10. Check the box Generate Waveform. Click the Simulate button to process
the simulation.
11. The waveform obtained after simulation is shown below.