| 摘要 |
PURPOSE: To reduce an electric consumption by making a power amplifier disuse by means of interrupting a stereo-electric signal such as music by an inaudible frequency signal through an electronic switch and of changing a time width of the interruption by using an infrasonic wave signal. CONSTITUTION: Inputs 11A and 11B are connected to head phone outputs of an external device 17A and 17B and the input 11A and 11B are put in a stereo head phone 6 through electronic switches 12A and 12B. The control of the electronic switches 12A and 12B are carried out by outputs from comparators 13A and 13B respectively. Signal from the infrasonic signal source 4 is added to the comparators 13A and a signal from an inverter 5 is added to the comparator 13B respectively. Also signals from the inaudible frequency source signal 14 are put in the other inputs of the comparators 13A and 13B respectively. Thus stereo-electric signal such as music is interrupted by inaudible frequency signals through the electronic switch and the time width of the interruption is changed by the infrasonic wave signals thereby a power amplifier comes to disuse. |
