Abstract: An improved method for adaptively cancelling acoustic feedback in hearing aids and other audio amplification devices. Feedback cancellation is limited to a frequency band that encompasses all unstable frequencies. By limiting the bandwidth of the feedback cancellation signal, the distortion due to the adaptive filter is minimized and limited only to the unstable feedback regions. A relatively simple signal processing algorithm is used to produce highly effective results with minimal signal distortion.

Abstract: An improved method for adaptively cancelling acoustic feedback in hearing aids and other audio amplification devices. Feedback cancellation is limited to a frequency band that encompasses all unstable frequencies. By limiting the bandwidth of the feedback cancellation signal, the distortion due to the adaptive filter is minimized and limited only to the unstable feedback regions. A relatively simple signal processing algorithm is used to produce highly effective results with minimal signal distortion.

Abstract: A reference transmitter (602) and reference receiver (604) are provided for testing the performance of a semi-implantable hearing aid. In a calibration configuration, an audiometer (606) is used to provide a reference signal via a headphone jack output (608) to the reference transmitter (602). The reference transmitter (602) provides an RF transmit coil output via lead (610) and coil (612) to the reference receiver (604). The reference receiver (604) provides an output signal that is correlated to a microphone signal to a hearing aid analyzer (616). The transmitter (602) and receiver (604) can be separately used to analyze the internal and external portions of a semi-implantable hearing aid using conventional audiometers and hearing aid analyzers.

Abstract: A decorrelation method for improving feedback cancellation utilizes a small frequency shifting ratio, on the order of 0.3 percent. Frequency shifting is applied only to the high frequency portion of the signal, which is shifted alternately upward and downward.

Abstract: An improved method for adaptively cancelling acoustic feedback in hearing aids and other audio amplification devices. Feedback cancellation is limited to a frequency band that encompasses all unstable frequencies. By limiting the bandwidth of the feedback cancellation signal, the distortion due to the adaptive filter is minimized and limited only to the unstable feedback regions. A relatively simple signal processing algorithm is used to produce highly effective results with minimal signal distortion.

Abstract: A reference transmitter (602) and reference receiver (604) are provided for testing the performance of a semi-implantable hearing aid. In a calibration configuration, an audiometer (606) is used to provide a reference signal via a headphone jack output (608) to the reference transmitter (602). The reference transmitter (602) provides an RF transmit coil output via lead (610) and coil (612) to the reference receiver (604). The reference receiver (604) provides an output signal that is correlated to a microphone signal to a hearing aid analyzer (616). The transmitter (602) and receiver (604) can be separately used to analyze the internal and external portions of a semi-implantable hearing aid using conventional audiometers and hearing aid analyzers.