Nonuniformity of coupled data transmission line profile to reduce crosstalk

Abstract

Signal bus lines interconnected between circuitry on PCB have been mostly layouted using uniform lines. The purpose of this paper is to present a synthesis method for nonuniform line profile that handles and reduces the crosstalk for high-speed pulse transmission in coupled lines without altering circuitry dimensions. The theory is based on the generalized taper theory containing control ability for input reflection coefficients without significant degradation of output waveform integrity. Transient responses of various line profiles are compared and the taper profile is extracted which is adequate to increase the average spacing between lines and to evenly reflect significant pulse spectra, hence drastically reducing the spike-like crosstalk peak level of sense line in the time domain.