Comprehensive crosstalk analysis application for real-time oscilloscopes

January 21, 2016 // By Graham Prophet
Keysight Technologies says that its crosstalk analysis tool can save you weeks when debugging crosstalk issues; running on the company’s real-time oscilloscopes, the application aids design decision-making, identifies the sources of crosstalk, quantifies how much each aggressor is disrupting victim signals, removes crosstalk from victim waveforms and uses eye-diagrams, jitter analysis and other tools to check how much margin can be recovered

N8833A and N8833B crosstalk analysis applications are written to assist in the diagnosis of crosstalk. The application not only detects and quantifies the presence of crosstalk, but it can determine which aggressors are primarily responsible; and can go one step further by actually removing the crosstalk from the victim waveform so engineers can visually compare the original waveform with the clean waveform side-by-side. Engineers can also compare the results from other scope analysis tools, such as real-time eye diagrams or jitter analysis. This gives engineers a direct way of quantifying the amount of improvement they can expect by mitigating the different sources of crosstalk.

The crosstalk analysis application can provide a lot of valuable insight into the design. For instance, it can help engineers determine the margins the design would recover without the crosstalk. It can also help determine if a signal that fails design specification can pass without the crosstalk. This can lead to important design decisions such as whether or not it is worth spending the time and effort to improve the crosstalk effect or where in the design to improve.

The combination of higher bit rates and tightly-spaced lines, Keysight observes, leads to an increased amount of crosstalk. Power supplies are also an important component. They can create interference on the data lanes they drive in the form of noise and jitter, and they themselves can be susceptible to data-dependent noise such as simultaneous switching noise, which leads to ground bounce.

The crosstalk analysis application can analyse up to four signals (aggressors or victims) at the same time. No additional simulation inputs or files are required. The application can handle different types of crosstalk including transmission line near-end crosstalk (NEXT) and far-end crosstalk (FEXT) as well as power supply aggressors, including power supply induced jitter (PSIJ), voltage-dependent amplitude noise and simultaneous switching network. The crosstalk-removed waveform can then be used with oscilloscope tools, such as E2688A SDA