Concurrent Multi-Channel Crosstalk Jitter Characterization Using Coprime Period Channel Stimulus

In recent years, the use of highly parallelized and high-speed data links has exacerbated the problem of crosstalk coupling. Signals with high frequency components couple to and degrade the quality of signals in adjacent lines aggressively with reduced device dimensions. In this paper, we propose a methodology for characterizing multiple crosstalk jitter effects in the time domain using a single data capture without the use of any channel models. The method uses repetitive data patterns across different signal lines with coprime periods. Each signal with crosstalk effects is digitized using sub-Nyquist sampling, and after back-end digital signal processing, the original transmitted signal on each line is isolated from its crosstalk components. Mathematical analysis shows that only by using patterns with coprime lengths, unbiased crosstalk characterization is possible. Hardware measurements support the proposed test methodology.