| 摘要 |
PURPOSE:To detect the end of a series of question and answer automatically, by monitoring the sound of two persons making questions and of a speaker. PURPOSE:No audio signal input is present to a priority input terminal 10, then a priority display terminal 11 is at high level and attenuation of control attenuators 3, 4 is at 0 dB. When an audio signal is inputted to an input terminal 20, after it is amplified at an audio mixing transmission amplifier 7, it is transmitted to an audio circuit 71. when an audio signal is inputted to the terminal 10, the attenuation of the control attenuator 4 is several 10 dB to block the audio signal inputted to the terminal 20. If the input is only given to the terminal 20, an audio detecting signal input terminal 502 of a controller 6 is at low level, and when an audio derecting signal input terminal 501 is at high level, the controller 6 gives priority to the input of the terminal 20 and a priority display terminal 21 is at high level. |
