The robust design of active noise control systems based on relative stability measures Available to Purchase

This paper presents a design method for active noise control (ANC) systems operating in a three‐dimensional nondispersive propagation medium based on an analysis of the relative stability of the inherent feedback loop. For practical systems the use of absolute stability is not useful; a system having an extremely long oscillatory response is unlikely to be accepted and would be liable to instability under small parameter variations. In this respect, a measure of the relative stability can provide a more acceptable design criterion. This procedure results in a robust design able to operate under changing operating conditions, with guaranteed system stability under stationary and slowly varying conditions. The frequency domain stability conditions are interpreted as spatial conditions on the geometry of the ANC system. Practical limitations in the design of the controller owing to the geometric configuration of the system are also discussed.