Patent ID: 6278786
Filing Date: 2001-08-21
Classification: A61F,G10K,H04R

Abstract:
An active noise cancellation aircraft headset system comprising:an earcup;a speaker mounted within the earcup for receiving and acoustically transducing a composite noise cancellation signal;a microphone mounted within the earcup for transducing acoustic pressure within the earcup to a corresponding analog error signal;an analog filter which receives the analog error signal and inverts it to generate an analog broadband noise cancellation signal;an analog to digital converter which receives the analog error signal and converts it to a digital error signal;a digital signal processor which receives the digital error signal and, using an adaptive digital feedback filter, generates a digital tonal noise cancellation signal;a digital to analog converter which converts the digital tonal noise cancellation signal to an analog tonal noise cancellation signal;summing means for receiving and summing the analog broadband noise cancellation signal and the analog tonal noise cancellation signal to generate the composite cancellation signal, the summing means providing the composite noise cancellation signal to the speaker to at least partially cancel aircraft noise within the earcup.