CATV system transmitting a scrambled television signal

Claim 3

A method as claimed in claim 1, wherein said color bursts are eliminated also in a second predetermined number of horizontal scanning periods after said vertical synchronizing signal portion.

Claim 6

An apparatus as claimed in claim 3, wherein said video signal processing means removes said color burst signal from said video signal also in a second predetermined period after said vertical synchronizing signal portion.

Claim 7

An apparatus as claimed in claim 3, wherein said video signal processing means comprises: synchronizing signal separation means having said video signal as an input and sampling out a horizontal synchronizing signal and a vertical synchronizing signal; burst position detection means having as an input said horizontal synchronizing signal and providing a first detection signal indicating a detection of said color burst; picture position detection means having as an input said horizontal synchronizing signal and providing a second detection signal indicating a predetermined positional relation between said horizontal synchronizing signal and said picture portion; odd field vertical synchronizing signal detection means, having as an input said horizontal synchronizing signal, for detecting an odd-field vertical synchronizing signal; counter means, having as an input said detection signal from said odd field vertical synchronizing signal detection means, for applying a count to a random generator means for generating first and second gate signals, said first gate signal indicating said color burst and said second gate signal indicating said picture portion; first and second pedestal level insertion means receiving said first and second gate signals, respectively, said first pedestal level insertion means removing color bursts when receiving a high level input, said second pedestal level insertion means having as an input a color-burst-eliminated video signal output from said first pedestal level insertion means and removing predetermined picture portions.

Claim 8

An apparatus as claimed in claim 3, wherein said encoder means comprises: synchronizing signal separation means, receiving an input video signal, for extracting a horizontal synchronizing signal and a vertical synchronizing signal from said video signal; first and second pulse generating means, having as inputs said horizontal synchronizing signal and said vertical synchronizing signal, for generating pulses; control means for controlling said first and second pulse generating means and for establishing a compression ratio corresponding to a predetermined number of said vertical synchronizing signals counted by said control means; and first and second switching means, responsive to said first and second pulse generating means, for compressing signals input thereto by predetermined amounts.

Claim 9

A CATV system in which, in a center apparatus, a video signal is compressed in a horizontal blanking interval and a vertical blanking interval and a key signal containing information concerning the compression is superimposed on an audio signal in said horizontal blanking interval, and a television signal containing said video and audio signal is transmitted from said center apparatus to each terminal apparatus, wherein said center apparatus comprises: video signal processing means for fixing a picture portion at a constant level in a first predetermined period before a vertical synchronizing signal portion, and for removing a color burst signal from a video signal at least in said first predetermined period before said vertical synchronizing signal portion; and encoder means for compressing said video signal in a horizontal blanking interval and a vertical blanking interval at a predetermined compression ratio, and for superimposing on an audio signal a key signal in said horizontal blanking interval and a pseudo-key signal in said vertical blanking interval in synchronism with a horizontal synchronizing signal, said key signal including information concerning the position of said vertical blanking interval; and said terminal apparatus comprises: in-band data detection means for detecting said information concerning the compression and said information concerning the position of said vertical blanking interval; and expansion means for expanding a received video signal in said horizontal blanking interval and said vertical blanking interval on the basis of said detected information concerning the compression and said information concerning the position of said vertical blanking interval.

Claim 10

A CATV system in which, in a center apparatus, a video signal is compressed in a horizontal blanking interval and a vertical blanking interval and a key signal containing information concerning the compression is superimposed on an audio signal in said horizontal blanking interval, and a television signal containing said video and audio signal is transmitted from said center apparatus to each terminal apparatus, wherein said center apparatus comprises: video signal processing means for fixing a picture portion at a constant level in a first predetermined period before a vertical synchronizing signal portion, and for removing a color burst signal from a video signal at least in said first predetermined period before said vertical synchronizing signal portion; and encoder means for compressing said video signal in a horizontal blanking interval and a vertical blanking interval at a predetermined compression ratio, and for superimposing on an audio signal a key signal in said horizontal blanking interval and a pseudo-key signal in said vertical blanking interval in synchronism with a horizontal synchronizing signal, said key signal including information concerning the position of said vertical blanking interval; and said terminal apparatus comprises: in-band data detection means for detecting said information concerning the compression and said information concerning the position of said vertical blanking interval; and expansion means for expanding a received video signal in said horizontal blanking interval and said vertical blanking interval on the basis of said detected information concerning the compression and said information concerning the position of said vertical blanking interval.

Claim 11

A CATV system as claimed in claim 7, wherein said video signal processing means removes said color burst signal from said video signal also in a second predetermined period after said vertical synchronizing signal portion.