N8833A Datasheet, PDF (5/15 Pages) Keysight Technologies – Crosstalk Analysis Application

05 | Keysight | N8833A and N8833B Crosstalk Analysis Application for Real-Time Oscilloscopes - Data Sheet
Crosstalk Network Models
The crosstalk application constructs different types of crosstalk models from the
measured waveforms depending on the victim and aggressor signal types. In the
simplest case, when both victim and aggressor are serial data signals, the model is a
linear n-port transfer function model. Figure 2 is simple example of a 2-channel serial
data system. Physically, the transmission system consists of two transmitters, two
receivers and a 4-port linear network model connected between them. Probing the two
serial data channels provides the input waveforms to the crosstalk application.
The application begins analyzing the waveforms by extracting the serial clock and data
pattern of each. It then uses the ideal data pattern as input to the 4-port linear crosstalk
model shown in figure 3. It computes the best-fit transfer function model, which
transforms the ideal waveforms into the actual measured waveforms. Within the model,
h₁₁ and h₂₂ represent the signal’s ISI while h₂₁ and h₁₂ represent the coupling or crosstalk
between the two signals. This approach allows the crosstalk analysis application to
remove the effect of either the crosstalk, ISI or both crosstalk and ISI from the measured
waveforms.
Figure 2. A 4-port network model for two parallel transmission lines. The black dots show possible
probe locations at the far end.
Figure 3. The crosstalk analysis application computes a 4-port linear crosstalk model, which
transforms the ideal waveforms into the actual measured waveforms.