Analysis of adaptive FIR filter pre-emphasis for high speed serial links

Due to the advances of technology in multimedia applications in recent years, the demand for high bandwidth point to point communication links has increased significantly. Jitter requirements have become more stringent with higher speed serial communication links. Jitter degrades the signal integrity at the receiver by introducing a timing deviation from the ideal or expected timing event. A proposal for reducing jitter, with the main focus on reducing data dependent jitter, is presented by employing adaptive finite impulse response (FIR) filter pre-emphasis. The channel bandwidth limitation, mainly caused by the skin effect of the conductor, and the parasitic components added by the integrated circuit package cause a nonflat frequency response and hence data dependent jitter. The pre-emphasis FIR filter is used to compensate for the frequency dependent chip package parasitic effects and the copper communication channel by altering the signal waveform before transmission. This paper presents the analysis and evaluation of adaptive FIR filter pre-emphasis to reduce data dependent jitter and to ultimately achieve higher data rates without adding significant implementation complexity. Simulation results on the adaptation scheme are also presented.