| 摘要 |
PURPOSE:To relieve restriction as against the posture of a transmitter during transmission and an interval between the mouth and the ear of a caller and to stabilize a transmission signal level by selecting and outputting only one microphone which is considered that a main sound source signal is inputted and whose power is the largest among three microphones. CONSTITUTION:A system consists of a handset 1, a receiver 2, a transmitter 3, directional microphones 4-6, amplifiers 8-10, rectifiers 11-13, low pass filters 14-16, a level selector 17 and a switch 18. The microphones 4-6 are horizontally arranged in such a way that the center axes of directivity are mutually parallel and at intervals so that sound receivable ranges where sound can be received by exceeding peripheral noise in a sound-uttering position are not overlapped. The switch circuit 18 compares the sound signal outputs of the microphones 4-6 and selects, switches and outputs the output from the microphones 4-6 having the largest output. Thus, restriction as against the posture of the handset during transmission and the interval between the mouth and the ear of the caller can be relieved and the transmission signal level can be stabilized. |
