A self-calibration scheme for extended frequency-band-decomposition sigma-delta ADC

Abstract

Frequency-band-decomposition (FBD) is a good candidate to be used to increase the bandwidths of ADC converters based on sigma-delta modulators for software and cognitive radio applications where we need to convert wide bandwidths. Each modulator processes a part of the band of the input signal which is then passed through a digital filter. In the case of large mismatches in the analog modulators, a new solution, called extended frequency-band-decomposition (EFBD) can be used. As an example, this solution can allow for a 4% error in the central frequencies without significant degradation of its performance when the digital processing part is paired with the analog modulators. A calibration of the digital part is thus required to reach these theoretical performances. This paper will focus on a self-calibration algorithm for an EFBD. The algorithm helps minimize the quantization noise of the EFBD and helps to flatten the signal transfer function.