Patent ID: 6996241

Claim:
A method of tuning an adaptive feedforward noise cancellation algorithm, comprising the acts of: providing a feedback active noise reduction (ANR) circuit, for providing an ANR error signal; providing a feedforward LMS tuning algorithm including at least first and second time varying parameters wherein said feedforward LMS tuning algorithm includes the formulas: y k =W k T X k and W k+1 =λ k W k +μ k X k e k adjusting said at least first and second time varying parameters as a function of instantaneous measured acoustic noise, a weight vector length and measurement noise variance, wherein said time varying parameters include: μ k = ⁢ μ o ⁢ λ k ( X k + Q k ) T ⁢ ( X k + Q k ) λ k = ⁢ ( X k + Q k ) T ⁢ ( X k + Q k ) - 2 ⁢ L ⁢ ⁢ σ q 2 ( X k + Q k ) T ⁢ ( X k + Q k ) wherein X k =X k +Q k is a measured reference signal; Q k is measurement noise, including electronic noise and quantization noise; σ q 2 is the known or measured variance of the measurement noise; L is the length of the LMS weight vector W k ; and e k is an error signal which is the net result of both the feedforward method and the feedback circuit.