JPS623176U - - Google Patents

Description

[Brief explanation of the drawing]

Figure 1 is a block diagram of one embodiment of the descrambling device for a television receiver of this invention, Figure 2 is a detailed block diagram of the mute circuit of Figure 1, and Figure 3 is a diagram of a conventional television receiver. FIG. 2 is a block diagram of a descrambling device. 4...AM demodulation circuit, 6...decoder section, 7...
... Switching amplification section, 8 ... Waveform shaping circuit, 9
... Miyuto circuit.

Claims (1)

[Scope of utility model registration request] A television receiver that suppresses the synchronization signal period of a video signal using an analog or digital scrambling key signal, and AM-modulates an audio carrier wave to receive a scrambled channel television broadcast signal and a normal channel television broadcast signal. In the descrambling device of the television receiver, which is provided in the television receiver and which descrambles the television broadcast signal of the scramble channel, AM demodulates the audio carrier wave of the received television broadcast signal, and outputs the demodulated signal only when the scramble channel is received. an AM demodulation circuit that performs waveform shaping on the demodulated signal, and a waveform shaping circuit that demodulates and outputs the key signal; an output signal of the shaping circuit and a subscriber information signal are input, and the information signal is used to perform the descrambling process. a decoder unit that outputs a control signal for canceling the suppression based on the key signal output from the waveform shaping circuit only when set; and a decoder unit that amplifies the received television broadcast signal and provides an amplification gain using the control signal. of the television broadcast signal of the scramble channel, and a mute circuit that controls the waveform shaping circuit to be inactive while the demodulated signal is not output. Descrambling device.