Patent ID: 8311234
Filing Date: 2012-11-13
Classification: H04M

Abstract:
1. An echo canceller for use in a sound reinforcement communication system for carrying out a sound reinforcement communication by utilizing a speaker and a microphone, the echo canceller comprising: an adaptive filter section for: adaptively identifying an impulse response of a feedback path formed by an acoustic coupling between the speaker and the microphone; estimating an echo component in the feedback path from an input signal to the feedback path, and subtracting the echo component from an output signal from the feedback path; and an echo suppressing section for executing echo suppressing processing of an output signal from the adaptive filter section; wherein the echo suppressing section: obtains an echo suppression amount based on Wiener Filtering by using an echo reduction amount based on a ratio of the amplitude of the input signal to the amplitude of the output signal from the adaptive filter section and multiplies the output signal from the adaptive filter section by the echo suppression amount calculates the echo suppression amount G(k) using an echo reduction amount based on a power of a short-time mean (short-time ERLE) and an echo reduction amount based on a power of a long-time mean (long-time ERLE), wherein G(k) ={(short-time ERLE)−(long-time ERLE)}/ [(short-time ERLE)·{1-(long-time ERLE)}]; and minimizes a revaluation amount ε, wherein: Y(k) is the echo-canceled output signal (residual signal) outputted from the echo canceller after execution of the echo suppressing processing; Er(k) is a residual echo signal contained in the residual signal; E[] represents a short-time mean of the expression within the brackets; and k is a frequency.