Patent ID: 7974428

Claim:
A hearing aid comprising: an input transducer for transforming an acoustic input signal into an electrical input signal, a signal processor for generating an electrical output signal, an output transducer for transforming the electrical output signal into an acoustic output signal, an adaptive filter for generating a feedback cancellation signal, a means for subtracting the feedback cancellation signal from the electrical input signal to produce a feedback-cancelled electrical input signal, a norm estimator for generating a first norm signal indicative of a norm N x of the electrical input signal and for generating a second norm signal indicative of a norm N fbc of the feedback-cancelled electrical input signal, a comparator for comparing the first norm signal with the second norm signal and generating a difference value N fbc −N x between the norm of the feedback-cancelled input signal and the norm of the electrical input signal, and a decision unit disabling the application of the feedback cancellation signal into the signal path of the hearing aid if the difference value is above a certain threshold value c th .