N8833B Crosstalk Analysis Application

Challenges the crosstalk analysis application addresses

• Identify the sources of crosstalk affecting the victim
• Quantify how much each aggressor is disrupting the victim
• Remove the effect of crosstalk from the victim signal for analysis
• Check how much design margin is recovered when crosstalk is removed from victim

Features of the crosstalk analysis application

• Analyze up to four signals (aggressors or victims) at once
• No crosstalk simulation or model is required when performing crosstalk analysis
• Identify and report the amount of crosstalk present on victims from each aggressors
• Plot waveforms without crosstalk. Compare them with the original waveforms using scope tools such as eye diagram and jitter separation to see how much margins can be recovered

Types of crosstalk that the crosstalk analysis application can analyze

• Transmission line aggressors: Near-End Crosstalk (NEXT) and Far-End Crosstalk (FEXT)
• Power supply aggressors: Power Supply Induced Jitter (PSIJ) and voltage-dependent amplitude noise
• Power supply victim: Simultaneous Switching Network (SSN)

Results reported by the crosstalk analysis application

• Inter-Symbol Interference (ISI) magnitude of the victim on itself
• Crosstalk magnitude of the transmission line aggressors on the serial data victim
• Crosstalk magnitude and jitter of the power supply aggressors on the serial data victim
• Crosstalk magnitude of the transmission line aggressors on the power supply victim

The need for increased speeds in data communications systems has led to higher data rates and parallel data lanes, which are necessarily placed closer together. The combination of higher bit rates and tightly-spaced lines lead to an increased amount of crosstalk. As a result, crosstalk is becoming a more important problem to diagnose. 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 are be susceptible to data-dependent noise such as Simultaneous Switching Noise (SSN), which leads to ground bounce.

Keysight has developed a crosstalk analysis application to assist in the diagnosis of crosstalk. The application not only detects and quantifies the presence of crosstalk, but it can also determine which aggressors are primarily responsible. It can go one step further by actually removing the crosstalk from the victim so you can visually compare the original waveform with the clean waveform side-by-side. You can compare the “before” and “after” waveforms directly on the scope display or by comparing the results from other scope analysis tools such as real-time eye diagrams or jitter analysis. This gives the user a direct way of quantifying the amount of improvement they can expect by mitigating the different sources of crosstalk.