Patent ID: 8218757
Filing Date: 2012-07-10
Classification: H04M

Abstract:
1. An echo canceller for cancelling an echo caused by an audio signal, comprising: an adaptive filter which is used both for performing echo cancellation and for detecting an echo occurrence position; and an adder, which adds a pseudo echo generated by the adaptive filter to the echo, so that the echo and the pseudo echo canceled to each other; a downsampling side signal path including a side performing the downsampling, which is a part of a subband filter and a sampling converter for downsampling the audio signal; a fullband echo cancellation side signal path for using the adaptive filter as a fullband echo canceller portion for the audio signal not flowing through the downsampling side signal path; a selector switch which appropriately switches between the downsampling side signal path and the fullband echo cancellation side signal path to input the audio signal; and a tap arrangement controller which optimizes a tap arrangement by using coefficients which are updated by the adaptive filter used for detecting the echo occurrence position by using a downsampled signal, the downsampled signal being generated through the downsampling by the subband filter and the sampling converter, the tap arrangement controller outputting the optimized tap arrangement to the adaptive filter; wherein, when the adaptive filter receives the tap arrangement optimized and outputted by the tap arrangement controller, the selector switch selects between the downsampling side signal path and the side performing the fullband echo cancellation, so that the adaptive filter is used for the fullband echo cancellation in accordance with the optimized tap arrangement.