Voice signal processing system mounted with echo canceller and voice signal processing method
AssigneeNEC Corporation
InventorsKazuhiko Koyama, Yasushi Numata
Life of this patent
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Abstract
In order to prevent generation of a trapezoidal signal waveform due to limitations on dynamic ranges in an echo canceller and an echo path as voice signal transmission paths, a voice signal processing circuit of the voice signal processing system processes a waveform such that its signal level falls within the narrowest dynamic range without causing an overshoot and waveform crack. Process of a signal waveform is selectively conducted only of a waveform of a voice signal whose signal level is high to be liable to have distortion. As to a voice signal whose signal level is low and originally within a dynamic range, the signal is transmitted without having its waveform processed.
Claims8
A voice signal processing system, comprising:
- an adaptive echo canceller for adaptively canceling echoes generated in an input/output transmission path to a communication terminal, and
- voice signal processing means for processing a waveform of a speech reception voice signal to be input to said communication terminal through said adaptive echo canceller into a waveform which is unlikely to have distortion.
A voice signal processing method, comprising:
- a voice signal processing step of processing a waveform of a speech reception voice signal to be input to a communication terminal through an adaptive echo canceller into a waveform which is unlikely to have distortion,
- a pseudo echo generation step of generating a pseudo echo by said adaptive echo canceller based on the speech reception voice signal processed at said voice signal processing step, and
- an adaptive echo canceling step of subtracting the pseudo echo generated at said pseudo echo generation step from a speech transmission voice signal which is transmitted from said communication terminal and contains an echo generated in an input/output transmission path to adaptively cancel said echo by means of said adaptive echo canceller.
Dependencies are inferred from the claim text.