Performance enhancement of sigma-delta modulator D-A converters using non-linear techniques

A new non-linear algorithm is presented for enhancing the performance of 1-bit sigma-delta modulator digital-to-analogue converters. The basis of the technique is to modify the operation of the quantizer in the loop so that a high pass quantization error is produced. This provides additional attenuation of quantization noise in the baseband, giving an increase in resolution synonymous with an increase in loop order. The algorithm is analysed and shown to be equivalent to a particular class of adaptive modulator. Furthermore, it is shown that the new algorithm has improved linearity over the standard modulator