Apparatus for noise shaping a pulse width modulation (PWM) signal and method therefor

Abstract

A method for preserving phase information during quantization of pulse width modulation (PWM) signals used in power system applications. In one embodiment, a digital audio amplifier (12) implements a method of noise shaping, where the quantization error is used in coordination with a noise shaping filter (64) to remove the noise from the desired baseband of the output. A phase-preserving expression is used to provide additional information for generating the amplified output (40). In one embodiment, the filter (64) includes a series of integrators (70, 72), where non-linear integration terms are added at each stage of integration to provide the phase information. In one embodiment the filter is implemented in software to run on a digital signal processor, and in another the filter is implemented in a hardware accelerator.

Dependencies are inferred from the claim text.