| 摘要 |
PROBLEM TO BE SOLVED: To increase an opportunity for realizing two-way simultaneous call by improving estimation precision in feedback gain and by controlling total loss more optimally than before so that the open-loop gain of a closed loop does not exceed one times. SOLUTION: At a maximum feedback gain estimator 55, the maximum feedback gain in feedback gains obtained for each frequency band is selected as the estimation value of the feedback gain. Thus, estimation precision is increased in the feedback gain as compared with a conventional example, where the feedback gain is estimated from time-average power of a reference signal, and hence controlling the total loss more optically than before so that the open-loop gain of the closed loop does not exceed one times and further increasing the opportunity for realizing the two-way simultaneous call. And a more comfortable call is realized even under an environment in which the call cannot be easily made normally since ambient noise, such as outdoor road noise and television noise in a room, occurs. COPYRIGHT: (C)2006,JPO&NCIPI |
