Distortionless analog-to-digital conversion

Abstract

Harmonic distortion is introduced by nonlinear flash analog-to-digital converters (ADCs) and even small-scale dithering does not reduce this unwanted effect. Large-scale dithering has been proposed to overcome this limitation. However, large-scale dithering is difficult to implement and, in addition, it severely reduces the ADC input dynamic range. In the paper, a new architecture is presented, based on ordinary flash conversion and dynamic element matching, that strongly reduces nonlinear distortion by randomizing the resistor positions in the resistor string used to generate the voltage references. Some properties of this architecture are analysed and simulation results are presented that validate the theoretical assumptions.