Signal Integrity Crosstalk Analysis in MATLAB

Hey there. In this video, we're going to dive into the world of crosstalk analysis with Signal Integrity Toolbox. So let's get started. This example contains three schematic sheets, an uncoupled single channel sheet and two multichannel sheets. The single channel sheet and multichannel sheets have the same topology except there is a victim channel with aggressors on either side in the multichannel sheets.

Each channel runs at 10 gigabits per second and has a topology consisting of a transmitter and receiver; a fixed 8-inch strip line trace; two microstrip traces separated by capacitors that vary from 3/4 of an inch to 1 and 1/2 inches, which is where the crosstalk coupling will occur; and some vias sprinkled about.

Let's talk about variation groups real quick because they will allow you to control the combinations of variable values to simulate. By using variation groups, you can reduce the number of simulations, which in turn allows for the simplified reporting of results. By associating two or more rows with the same variation group name, you can lock those variations to sweep together. Thus, you can reduce what would have been almost 2,600 simulations down to just 28, a real time-saver.

You can evaluate industry standard crosstalk metrics like insertion loss to crosstalk ratio, integrated crosstalk noise, and power-sum crosstalk. Rules files, which contain industry standard maps for ICR, ICN, and crosstalk, can be used to analyze different aspects of crosstalk. There are two modes for crosstalk analysis in Signal Integrity Toolbox, Semi-Analytic, and Explicit.

When using Semi-Analytic, each channel is simulated in the absence of crosstalk and an eye diagram is constructed using the recovered clock. Then the probability density function of the crosstalk is calculated and convolved with the eye diagram to generate a bathtub curve and to estimate the BER.

When in Explicit mode, all channels in the system are simulated simultaneously in the time domain. This means that the waveform at the receiver is the combined result of the victim channel and the crosstalk aggressors. After the simulations are complete, you can view the results in the Signal Integrity Viewer app. You can plot ICR, ICN, empower some crosstalk using a variety of displays.

You can plot them versus specification limits. You can plot the unequalized signal-to-noise ratio versus ICR, ICN, and power-sum crosstalk. You can compare statistical eye diagram with crosstalk against one without.

You can also view a histogram of just the crosstalk as well. You can compare the results of the semi-analytic crosstalk method to the explicit with eye masks. You can also view the time domain waveforms and see just how crosstalk affects the waveform when using the explicit method.

To wrap up, Signal Integrity Toolbox is a powerful tool for crosstalk analysis, with variation groups, rules files, and multiple crosstalk analysis modes. Crosstalk analysis is easier than ever. If you want to learn more about Signal Integrity Toolbox and continue exploring its capabilities, check out MathWorks.com for more examples and other helpful resources. Thanks for watching.