Noise Weighting in the Design of \Delta\Sigma Modulators (With a Psychoacoustic Coder as an Example)

• Published in: IEEE transactions on circuits and systems. II, Express briefs Vol. 60; no. 11; pp. 756 - 760
• Main Authors: Callegari, Sergio, Bizzarri, Federico
• Format: Journal Article
• Language: English
• Published: IEEE 01.11.2013
• Subjects: Delta-sigma modulation; Finite impulse response filters; Frequency modulation; Noise; noise shaping; Optimization; Psychoacoustic models; psychoacoustics; Quantization (signal)
• ISSN: 1549-7747; 1558-3791
• DOI: 10.1109/TCSII.2013.2281892

A design flow for ΔΣ modulators is illustrated, allowing quantization noise to be shaped according to an arbitrary weighting profile. Based on finite-impulse-response noise transfer functions, possibly with high order, the flow is best suited for digital architectures. This work builds on a recent proposal in which the modulator is matched to the reconstruction filter, showing that this type of optimization can benefit a wide range of applications in which noise (including in-band noise) is known to have a different impact at different frequencies. The designs of a multiband modulator, a modulator avoiding dc noise, and an audio modulator capable of distributing quantization artifacts according to a psychoacoustic model are discussed as examples. A software toolbox is provided as a general design aid and to replicate the proposed results.