Noise Transfer Function Design and Optimization for Digital Sigma-Delta Audio DAC

The parameters of sigma-delta audio DAC depend mainly on digital sigma-delta
modulator’s features, especially on its noise transfer function (NTF). Many methods
of design and optimization of the loop filter’s coefficients in sigma-delta modulators
have been proposed so far. These methods enable the designer to get suitable noise
transfer functions for specific application. This paper reviews NTF design and optimization
methods which are particularly useful in audio applications.