ECHO CANCELLING USING SIGNAL PREPROCESSING IN AN ACOUSTIC ENVIRONMENT

摘要

An echo suppression apparatus has a number of sensors, such as microphones, disposed in an environment. Each sensor receives a signal. Each of the signals includes a component derived from an echo source in the environment. The echo source may be one or more loudspeakers which, in combination with the microphones, are part of a hands-free communication device. The echo suppression apparatus further includes a processor for processing the received signals based on spatial and/or temporal information in order to transform the received signals into a processed signal having a reduced component derived from the echo source. In accordance with another aspect of the invention, the echo source is one or more loudspeakers having input signals derived from an electronic signal, and the echo suppression apparatus may further include an echo canceler component for generating an echo replica from the electronic signal, wherein the echo replica approximates the reduced component derived from the echo source. The echo replica is then subtracted from the processed signal in order to further reduce the amount of echo that is perceived by a far-end user. The processor and the echo canceler component may, for example, each be adaptive finite impulse response (FIR) filters whose tap weights are dynamically determined.