Patent ID: 6539091
Filing Date: 2003-03-25
Classification: H04M

Abstract:
An apparatus for acoustical sidetone damping, comprising:a reception branch having a speaker and receiving an input signal; a transmission branch having a microphone for transmitting an output signal; an adaptive echo compensator for compensating for an echo in said transmission branch, said adaptive echo compensator adaptively filtering the input signal of said reception branch for producing a filtered signal, and subtracting the filtered signal from the output signal of said transmission branch resulting in a compensated output signal; a damping device for damping at least one of the compensated output signal of said transmission branch and the input signal of said reception branch; a correlator for determining and outputting a correlation measurement signal, the correlation measurement signal derived from the input signal of said reception branch and the output signal of said transmission branch; a control device connected to said adaptive echo compensator and to said damping device, said control device outputting control signals for adaptation of said adaptive echo compensator and for adjusting damping of said damping device, said control device receiving an average signal magnitude of the input signal and an average signal magnitude of the compensated output signal, said control device receiving the correlation measurement signal; and an excitation detector for receiving the average signal magnitude of the input signal, comparing the average signal magnitude to a predetermined average magnitude, and outputting an excitation signal if an adequate average signal magnitude of the input signal is present.