KR960033102A - Cable TV's Improved Receiver - Google Patents

Abstract

The present invention relates to an improved receiver for CATV, wherein a horizontal line video signal from a transmitting station is converted from an A / D converter into a digital horizontal line video signal, and is based on a reference value extraction pulse from a pulse generator. The reference level transmitted from the transmitting station is detected in the signal processing circuit, and the horizontal line video signal scrambled based on the descramble control signal from the control unit is inverted in the signal inverting unit so that the analog horizontal line video signal is switched in the D / A converter. Since the scrambled horizontal line video signal is digitally descrambled, it is possible not only to accurately detect the reference level transmitted from the transmitting station, but also to quickly cope with a change in the reference level over time.

Description

Cable TV's Improved Receiver

Since this is an open matter, no full text was included.

1 is a block diagram schematically showing an improved receiver of a cable TV according to a preferred embodiment of the present invention.

2 is a detailed view of the digital signal processor of FIG.

3 is a diagram illustrating a reference value extraction pulse for detecting a horizontal line image signal and a reference signal transmitted from a transmitting station according to a preferred embodiment of the present invention.

Claims (1)

Inputs scramble information transmitted from the transmitting station of a tuner for tuning a broadcast signal of a channel corresponding to a selection control signal among broadcast signals transmitted from the transmitting station, and transmits information on the channel selected by the subscriber from the receiver. And a control signal for descrambling on the basis of the selection control signal for tuning the broadcast signal of the corresponding channel and the scramble information from the modem when a channel for output by the subscriber and a channel by the subscriber's operation are selected. Control means, voice detection means for detecting an audio signal among the broadcast signals tuned by the tuner, video detection means for detecting an image signal among the broadcast signals tuned by the tuner, and descramble from the control means. The video signal scrambled by the transmitting station based on the control signal for In a receiver of a CATV comprising descrambling means for descrambling, the descrambling means comprises: A / D conversion means for converting an analog video signal detected by the video detecting means into a digital video signal based on a sampling pulse. ; Pulse generating means for detecting a horizontal synchronizing signal among the image signals detected by the image detecting means and generating a reference value extraction pulse, an effective image pulse, and the sampling pulse based on the horizontal synchronization signal; Reference level detecting means for detecting the level of the reference signal transmitted from the transmitting station based on the reference value extraction pulse from the pulse generating means; Signal inverting means for inverting the video signal around the reference level detected by the reference level detecting means based on a control signal for descramble from the control means; Reference signal removing means for removing a reference signal carried in the video signal from the transmitting station in the video signal through the signal inverting means; And an D / A converting means for converting the video signal converted into digital signal from the A / D converting means into an analog video signal. ※ Note: The disclosure is based on the initial application.