Patent ID: 7248708

Claim:
An adaptive noise canceling microphone system comprising: a first microphone for generating a first microphone signal containing primarily speech and noise; a second microphone for generating a second microphone signal containing primarily noise; a first adaptive filter comprising a single filter coefficient wherein the first adaptive filter is adapted to: generate a first output signal from the second microphone signal; and generate a first error signal, wherein the first error signal is generated by subtracting the first output signal from the first microphone signal; a second adaptive filter comprising multiple filter coefficients, wherein the second adaptive filter is adapted to: generate a second output signal from the second microphone signal; and generate a second error signal, wherein the second error signal is generated by subtracting the second output signal from the first error signal: and first and second adaptive convergence controllers, wherein the first adaptive convergence controller is adapted to change a rate of convergence of the first adaptive filter based on the first error signal and the second adaptive convergence controller is adapted to change a rate of convergence of the second adaptive filter based on the second error signal.