Video signal processing system
AssigneeClarion Co., Ltd.
InventorHiroshi Osaka
Life of this patent
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Abstract
A video signal processing system in which a synchronizing signal component of a television video signal is inverted with reference to a pedestal level and expanded higher than a video component and horizontal synchronizing signals are reduced so that each of the horizontal synchronizing signals may correspond to plural lines.
Claims7
A video signal processing system in a wireless pay-television system wherein a television video signal is encoded by an encoder, the coded signal is transmitted to subscribers' ends, and the coded signal received at the subscribers' ends is decoded into an ordinary video signal by decoders, said video signal having a video component and a synchronizing signal component,
- which system is characterized in that said encoder processes and encodes the television video signal by inverting said synchronizing signal component thereof with reference to a pedestal level and amplifying said synchronizing signal component so that it is higher than said video component and by reducing the number of horizontal synchronizing signal components so that one of the horizontal synchronizing signal components remains for a plurality of lines,
- said encoder comprising:
- a synchronizing separation circuit for separating a composite synchronizing signal from the television video signal;
- a vertical synchronizing signal separating circuit driven by the composite synchronizing signal to produce a vertical synchronizing signal;
- a cycle equalizing circuit driven by the composite synchronizing signal to produce a continuous wave signal having a cycle equal to that of a horizontal synchronizing signal;
- a clock signal generating circuit for producing a clock signal;
- a synchronizing signal generating circuit responsive to the vertical synchronizing signal, the continuous wave signal and the clock signal to produce at least a horizontal drive signal, a vertical drive signal and the composite synchronizing signal;
- a switching signal generating circuit for producing a switching signal in response to the horizontal and vertical drive signals, a pulse duration of the switching signal being selected so as to cover the horizontal synchronizing signal and the vertical synchronizing signal including the equalizing pulses in said composite synchronizing signal but exclude a color burst signal and the video signal component;
- a scrambler signal generating circuit responsive to the horizontal drive signal, the vertical drive signal and the composite synchronizing signal for mixing the horizontal synchronizing signal having a frequency of the horizontal drive signal divided by an integer and the vertical synchronizing signal including the equalizing pulses to produce a scrambling synchronizing signal;
- and
- a video signal switching circuit driven by the switching signal to selectively output the video signal or the scrambling synchronizing signal.
Dependencies are inferred from the claim text.