Design of Oversampling Δ Σ DA Converters Via H∞ Optimization

In this paper, we propose a new method for designing oversampling DeltaSigma DA converters via H^infin optimization. The design consists of two steps. One is that for DeltaSigma modulators. In DeltaSigma modulators, the accumulator 1/(z - 1) is conventionally used in a feedback loop to shape quantization noise. In contrast, we give all stabilizing feedback filters for the modulator, and propose an H^infin design to shape the frequency response of the noise transfer function (NTF). The other is a design for interpolation filters in oversampling DA converters. While conventional designs are executed in the discrete-time domain, we take account of the characteristic of the original analog signal by using sampled-data H^infin optimization. A design example is presented to show that our design is superior to conventional ones