Mu robustness analysis of adaptive feedforward noise cancelling algorithms

Robust control theory is applied to analyzing a class of adaptive feedforward algorithms which are commonly used for cancelling sinusoidal noise. It is shown that by using a previously developed LTI/LTV decomposition, sufficient conditions for robust stability can be established in terms of the structured singular value. This approach differs significantly from more accepted methods of adaptive analysis using hyperstability, Lyapunov functions, etc., and leads to important insights when studying robust stability properties of the adaptive system.