A/D conversion based on signal decomposition for DSP applications

Abstract

Digital Signal Processing (DSP) systems operating on analog inputs are often limited by sampling rates of Analog to Digital Converters (ADC). ADCs are critical components since they tend to determine the overall system performance. Hence it is important that ADCs possess characteristics like high sampling rate, low conversion delay and high resolution that enhance system performance. In this paper, we propose a novel ADC to be used in signal processing based on signal decomposition. The proposed scheme folds the input signal symmetrically prior to quantization by high speed comparators. However, unlike folding ADCs that divide the input analog signal into two components, corresponding to coarse and fine quantization, the proposed converter minimizes delay and circuit complexity by introducing a Folding Bit. It does not use explicit circuits for coarse and fine quantization but uses only folding circuits to generate both most significant and least significant bits directly eliminating synchronizing problems normally encountered in the recombination of coarse and fine quantized bits.