Engineering Brief
Open Access
Noise and Distortion Mechanisms Encountered in Switching Audio Power Amplifier Design
AES Convention 147 · Paper 549 · October 2019
Abstract
When designing a switching power amplifier, many phenomena are encountered that leave the designer wondering why performance falls short of what theory predicts. While many sources of non-linearity and noise in the conversion process are known and intrinsic to the sub-systems involved, other sources of error are more subtle. The intent of this paper is to outline the noise, distortion, and error mechanisms commonly encountered in practice when designing a switching (Class-D) power amplifier. By understanding the root cause of these mechanisms, a more heuristic approach can be employed in switching power amplifier design. The focus will be on analog systems employing clocked, naturally sampled modulators, but the bulk of the material will be broadly applicable to any modulation scheme.
