Time-mode circuits for analog computation

We introduce time-mode circuits, a set of basic circuit building blocks for analog computation using a temporal step function representation for the inputs and outputs. These novel time-mode circuits are low power, provide good noise performance and offer improved dynamic range. The design, IC implementation and detailed theoretical signal-to-noise ratio (SNR) analysis of a prototype time-mode circuit—a weighted average computation circuit—are discussed. This new way of computation is studied with respect to existing conventional voltage-mode and current-mode circuits. Two possible applications of these time-mode circuits are presented: an edge detection circuit for 16 pixels and a 3-tap FIR filter that provides an SNR of 64 dB. Copyright © 2008 John Wiley & Sons, Ltd.