Modeling and analysis techniques of jitter enhancement across high-speed interconnect systems

Although it is well understood that a band-limited passive system can be a source of deterministic jitter, it is less obvious that the deterministic and random jitters generated by the clock or data source can be enhanced significantly by the passive channel. In this paper, modeling and simulation techniques to predict jitter enhancement across interconnect systems are presented. The conventional method of using SPICE to calculate output jitter is computationally expensive. Instead, the effect of channel on input jitter can be represented by jitter impulse response or jitter transfer function in time or frequency domains, respectively. These jitter characteristic functions can then be used to efficiently determine the increase in jitter as signal propagates across an interconnect system. The probability mass function of jitter impulse response can also be constructed to statistically predict the jitter enhancement at lower bit-error rate. Finally, the results form SPICE-based simulation and those obtained using the jitter characteristic functions are compared.