| 摘要 |
PURPOSE:To attain sufficient scramble even to an audio signal by providing a means stopping a matrix processing of a matrix circuit so as to introduce a demodulation output of a subchannel signal when a specific key data is inputted. CONSTITUTION:The system is provided with means 233-237, 241-246 identifying a mode signal and applying matrix processing to a demodulation output of main and subchannel signals when the signal represents the stereo mode and a means 211 stopping the matrix processing operation of a matrix circuit 250 to introduce the demodulated output of the sub channel signal when a specific key data is inputted regardless of the mode signal representing the stereo mode. Thus, only a subscriber acquiring the specific key data or recognizing it listens to the demodulation output of the subchannel signal as an audio signal and a terminal equipment not acquiring the specific key data cannot listen to the audio signal because noise is subject to matrix processing. |
