Controlled Intersymbol Interference Design Techniques of Conventional Interconnect Systems for Data Rates Beyond 20 Gbps

This paper presents a new design technique of high-speed interconnects with controlled intersymbol interference (ISI) to create efficient signaling over a band-limited channel. Performance of high-speed electrical links is limited by conductor loss, dielectric dispersion, and reflections in the board, package, and connector. These nonidealities result in significant ISI. In current systems, the effect of ISI is either mitigated through complex equalization, signal conditioning, and coding techniques, or through costly impedance control and manufacturing processes. In the proposed approach, instead of eliminating ISI, we shape the response of the channel into a set of channel characteristics with controlled ISI using simple passive structures in the board and the package. The resulting controlled ISI is exploited at the transmitter and receiver to simplify the architecture of the system and to achieve high data rates. The techniques to design interconnects with controlled ISI are reasonably simple to implement in conventional interconnect technologies. Simulation examples are given to demonstrate the validity and advantages of the design technique using duobinary and analog multitone (AMT) signaling methods.