Echo canceling method, echo canceller, and voice switch

Abstract

A digitized input signal is sampled, to obtain a reference input signal. The reference input signal is spuriously whitened, to obtain a pseudo whitened signal. An echo replica signal is generated on the basis of the pseudo whitened signal and an adaptive filter coefficient. A cancellation error signal is obtained on the basis of an echo signal and the echo replica signal. The adaptive filter coefficient is updated on the basis of the cancellation error signal, the adaptive filter coefficient, and the pseudo whitened signal.

1 - 4 . (Canceled)  
     
     
         5 . A voice switch comprising: 
 near-end speaker's voice judgment means for judging whether a near-end speaker's voice is present or absent;    far-end speaker's voice judgment means for judging whether a far-end speaker's voice is present or absent; and    speech communication state determination means for determining which of a near-end speaker speech communication state, a far-end speaker speech communication state, and an intermediate state is the current speech communication state on the basis of the results of the judgment by the near-end speaker's voice judgment means and the far-end speaker's voice judgment means, the preceding speech communication state determined, and the hysteresis of speech communication states preceding the preceding speech communication state.    
     
     
         6 . The voice switch according to  claim 5 , wherein 
 the speech communication state determination means comprises, in a case where the transition from the near-end speaker speech communication state or the far-end speaker speech communication state to the intermediate state occurs, means for    determining, when it is judged that the near-end speaker's voice or the far-end speaker's voice is present after the intermediate state is continued for not less than a predetermined time period, the speech communication state so as to proceed to a speaker speech communication state corresponding to the speaker's voice which is judged to be present,    determining, when it is judged that the speaker's voice in a direction of speech communication before the transition to the intermediate state is present in a case where the time period during which the intermediate state is continued is shorter than said predetermined time period, the speech communication state so as to immediately return to a speaker speech communication state before the transition, and    determining, even when it is judged that the speaker's voice in a direction of speech communication opposite to the direction of speech communication before the transition to the intermediate state is present in a case where a time period during which the intermediate state is continued is shorter than said predetermined time period, the speech communication state so as to maintain the intermediate state.    
     
     
         7 . The voice switch according to  claim 5 , wherein a plurality of types of intermediate states are set.  
     
     
         8 . A voice switch comprising: 
 near-end speaker's voice attenuation means for attenuating a near-end speaker's voice;    far-end speaker's voice attenuation means for attenuating a far-end speaker's voice;    near-end speaker's voice judgment means for judging whether the near-end speaker's voice is present or absent;    far-end speaker's voice judgment means for judging whether the far-end speaker's voice is present or absent;    speech communication state determination means for determining which of a near-end speaker speech communication state, a far-end speaker speech communication state and an intermediate state is the current speech communication state on the basis of the results of the judgment by the near-end speaker's voice judgment means and the far-end speaker's voice judgment means, the preceding speech communication state determined, and the hysteresis of speech communication states preceding the preceding speech communication state;    means for controlling, when it is determined that the current speech communication state is the near-end speaker speech communication state, an attenuation amount by the near-end speaker's voice attenuation means at a low level, while controlling an attenuation amount by the far-end speaker's voice attenuation means at a high level;    means for controlling, when it is determined that the current speech communication state is the far-end speaker speech communication state, an attenuation amount by the near-end speaker's voice attenuation means at a high level, while controlling an attenuation amount by the far-end speaker's voice attenuation means at a low level; and    means for controlling, when it is determined that the current speech communication state is the intermediate state, both the attenuation amount by the near-end speaker's voice attenuation means and the attenuation amount by the far-end speaker's voice attenuation means at an intermediate level,    the speech communication state determination means comprising means for determining, when the transition of the speech communication state between the near-end speaker speech communication state and the far-end speaker speech communication state occurs, the speech communication state such that the transition always occurs via the intermediate state.    
     
     
         9 . The voice switch according to  claim 8 , wherein the speech communication state determination means comprises, in a case where the transition from the near-end speaker speech communication state or the far-end speaker speech communication state to the intermediate state occurs, means for 
 determining, when it is judged that the near-end speaker's voice or the far-end speaker's voice is present after the intermediate state is continued for not less than a predetermined time period, the speech communication state so as to proceed to a speaker speech communication state corresponding to the speaker's voice which is judged to be present,    determining, when it is judged that the speaker's voice in a direction of speech communication before the transition to the intermediate state is present in a case where the time period during which the intermediate state is continued is shorter than said predetermined time period, the speech communication state to immediately return to a speaker speech communication state before the transition, and    determining, even when it is judged that the speaker's voice in a direction of speech communication opposite to the direction of speech communication before the transition to the intermediate state is present in a case where the time period during which the intermediate state is continued is shorter than said predetermined time period, the speech communication state so as to maintain the intermediate state.    
     
     
         10 . The voice switch according to  claim 8 , wherein a plurality of types of intermediate states are set.