Analysis of the non-uniform samplings in sigma-delta modul ated signals

Abstract

The effects of non-uniform sampling in the EA-modulated DAC are discussed in this paper. The non-uniform sampling of the EA-modulated signals causes in-hand noise in the DAC, which will be compared with the harmonic distortions in switched capacitor circuit and the that due to the signal-dependent nonlinearity in the 1-hit DAC. We describe an error-driven edgeselection ulgorithm that suppresses the in-band noise and its implementation. We also propose a model of the in-band noise caused by the non-uniform sampling, which predicts tlhe noise reduction of the spectral shaping in the frequency domain quantitatively based upon the transition probability of the modulator output.