| 摘要 |
PURPOSE:To prevent a sound image from flickering even at the time of double talk by performing stereo sound transmission at the time of double talk and performing monaural transmission only at the time of a single utterance. CONSTITUTION:By a first monaural sound encoder 101, the sum of the outputs of left and right microphones is compressed and encoded to e.g. 56kbps. By a detector 102, a level difference, a delay difference between the output signals of left and right microphones and the difference between the single utterance and plural simultaneous utterance are detected and encoded to e.g. 8kbps. By second and third monaural sound encoders 103, 104, the output signals of left and right respective microphones are encoded to a bit rate lower than the first monaural sound encoder 101 e.g. 32kbps individually at the time of plural simultaneous utterance. Thus, the stereo sound transmission is performed with high quality and in pesudo by the first monaural sound encoder 101 at the time of the single utterance, and the stereo sound transmission is performed perfectly and left and right individually by the second and third monaural sound encoders 103, 104 at the time of plural simultaneous utterance. |
