| 摘要 |
PROBLEM TO BE SOLVED: To make howling or an echo not be easily generated by separating a signal outputted from a means to be commanded into a transmitting speech signal and a receiving speech signal and obtaining the average value of outputs in accordance with the outputs of a control circuit for automatically controlling a gain. SOLUTION: When a commander gives a command to the telephones sets 10-10n to be commanded of a person to be commanded from a command desk 20, the voice of the commander is covered into electric signals through a microphone 20. The signals are digitally converted by an encoder 21 and respectively transmitted to respective commanded person sides. The transmitted signals are transmitted to decoders 13-13n and the person to be commanded recognize command contents through the telephone sets 10-10n. When the person to be commanded has a question, etc., about the command contents, his name is announced. The voice is separated into the transmitting signals by hybrid circuits 11-11n through the telephone sets 10-10n, converted into the digital signals by the encoders 12-12n, mixed with the signals of another person to be commanded by an adder 16 and heard by the commander through a speaker 22. |
