Patent ID: 8194850

Claim:
A voice communication device, comprising: a speaker for outputting a local output signal; a microphone, receiving a local input signal while the speaker is outputting the local output signal, wherein the local input signal comprises ambient noise and echo of the local output signal; a first filter bank, performing a subband decomposition on the local output signal to generate a plurality of first subband signals each corresponding to a subband; a second filter bank, coupled to the microphone, performing the same subband decomposition on the local input signal to generate a plurality of second subband signals each corresponding to a subband; a plurality of processing units each corresponding to a subband, coupled to the first and second filter banks to perform noise reduction and echo cancellation based on each pair of first and second subband signal inputs; and a synthesis filter bank, coupled to the processing units, synthesizing the qualified results output from the processing units to generate an outbound signal in which echoes are cancelled and noises are suppressed, wherein each of the processing units performs a short-term DFT analysis on the subbands before performing noise reduction, and wherein each subband is decomposed into a plurality of narrow frequency bins, and noise reduction is performed per narrow frequency bin, each processing unit comprises: an echo canceller, performing echo cancellation based on a pair of first and second subband signal input to generate a cancellation result; a Discrete Fourier Transform (DFT) unit, performing short-term DFT analysis to decompose the cancellation result into a plurality of transformed signals each corresponding to a narrow frequency bin; a plurality of noise suppressors coupled to the DFT unit, each corresponding to a narrow frequency bin, performing noise suppression on the transformed signals to generate a plurality of noise suppression results; an Inverse Discrete Fourier Transform (IDFT) unit, coupled to noise suppressors, performing short-term IDFT synthesis to reassemble the suppression results into a de-noised result; and a nonlinear processor, coupled to the IDFT unit, suppressing residual echo in the de-noised result to generate a qualified result as an input to the synthesis filter bank, and wherein the results from each echo canceller are grouped into a frame of M samples per frame time, in which the first M/2 samples of the current frame are identical to the last M/2 samples of the previous frame.