| 摘要 |
PURPOSE:To eliminate the necessity of connecting a transmitter by a cable by providing in the house of a a subscriber a receiver to demodulate a video signal and an audio signal modulated by a station code into an original video signal and audio signal. CONSTITUTION:Station code demodulators 26 and 27 supplied from a broadcasting station and change-over switches 28 and 29 are additionally provided on a receiver 20 of the subscriber who makes a contract with the broadcasting station. A modulated video signal V' and a modulated audio signal A' received by an antenna 21 are respectively transmitted to the station code demodulators 26 and 27, the modulated video signal V' transmitted from a video demodulator 24 is demodulated by a station code C and the original video signal V is generated. On the other hand, in the receiver which does not yet make a contact with the broadcasting station, since the modulated video signal V' and the modulated audio signal A' outputted from the video demodulator 24 and an audio demodulator 25 are directly transmitted to a picture receiving tube and a speaker, the original video and audio cannot be obtained. |
