Nonidealities in traveling wave and transversal FIR filters operating at microwave frequencies

We examine the effects of transmission-line nonidealities like series loss, terminal impedance mismatch, circuit noise, and transconductor input and output capacitances on the performance of traveling-wave (TWA) and transversal finite-impulse response (FIR) filters. A general framework is presented for the analysis and simulation of such filters in the context of a real communication channel. Simulation results for adaptive equalizers operating at a data rate of 10 Gbps are given. Intuition is derived for the vastly superior performance of TWA-FIR filters. We also show that the effects of series losses can be counteracted in some measure by deliberately misterminating the transmission lines with a resistance lower than their characteristic impedance.