Method and apparatus for generating a signal that defeats illegal cable decoders

Method of defeating an illegal black box it used to overcome the effect of a scrambled video signal thereby presenting an unviewable picture to an unauthorized user of the black box comprising:

• generating a jamming signal of unreliable vertical rate signal characteristics;
• and
• superimposing or inserting the jamming signal on the scrambled video signal during a time duration which at least encompasses vertical blanking intervals of the video signal to cause the illegal black box to generate unstable vertical rate signals and thus the unviewable video signal;
• wherein:
• the jamming signal is a time varying voltage generally of blanking level to peak white level;
• and
• the step of superimposing or inserting includes:
• removing the broad vertical pulses of the vertical sync from selected video lines generally in the vertical blanking interval;
• and
• adding the jamming signal in the selected video lines generally in the vertical blanking interval.

Method of defeating an illegal black box used to overcome the scrambling effect of a scrambled video signal thereby presenting an unviewable picture to an unauthorized user of the black box comprising:

• generating a jamming signal of unreliable vertical rate signal characteristics;
• and
• superimposing or inserting the jamming signal onto the scrambled video signal during a time duration which at least encompasses vertical blanking intervals of the video signal to cause the illegal black box to generate unstable vertical rate signals and thus the unviewable video signal;
• wherein:
• the jamming signal is a line fill signal whose video level follows the program signal level of the scrambled video signal;
• and
• the step of superimposing or inserting includes inserting the line fill signal into the scrambled video signal during the vertical blanking interval.

Method of defeating an illegal black box used to overcome the scrambling effect of a scrambled video signal thereby presenting an unviewable picture to an unauthorized user of the black box comprising:

• generating a jamming signal of unreliable vertical rate signal characteristics;
• and
• superimposing or inserting the jamming, signal on to the scrambled video signal during a time duration which at least encompasses vertical blanking intervals of the video signal to cause the illegal black box to generate unstable vertical rate signals and thus the unviewable video signal;
• wherein:
• the jamming signal is a color burst signal;
• and
• the step of superimposing or inserting includes:
• adding color burst signal to each of the video lines in the vertical blanking interval that normally do not include color burst signals.

Method of defeating an illegal black box used to overcome the scrambling effect of a scrambled video signal thereby presenting an unviewable picture to an unauthorized user of the black box comprising:

• generating a jamming signal of unreliable vertical rate signal characteristics;
• and
• superimposing or inserting a the jamming signal onto the scrambled video signal during a time duration which at least encompasses vertical blanking intervals of the video signal to cause the illegal black box to generate unstable vertical rate signals and thus the unviewable video signal;
• wherein:
• the jamming signal is an incorrect modification of a proper color burst signal;
• and
• the step of superimposing or inserting includes:
• inserting the incorrect modification of the proper color burst signal in place of the proper color burst signal in the horizontal blanking intervals or in the horizontal sync vicinity of respective video lines in the vertical blanking intervals;
• and
• relocating the proper color burst signal within the horizontal blanking intervals.

Method of defeating an illegal black box used to overcome the scrambling effect of a scrambled video signal thereby presenting an unviewable picture to an unauthorized user of the black box comprising:

• generating a jamming signal of unreliable vertical rate signal characteristics;
• and
• superimposing or inserting the jamming signal onto the scrambled video signal luring a time duration which at least encompasses vertical blanking intervals of the video signal to cause the illegal black box to generate unstable vertical rate signals and thus the unviewable video signal;
• wherein:
• the jamming signal includes a position modulated erroneous clamp pulse;
• and
• the step of superimposing or inserting includes:
• adding an edge fill or insertion signal at the end of the respective video line;
• and
• modulating the added edge fill or insertion signal its well as the erroneous clamp pulse.

Apparatus for defeating an illegal black box used by unauthorized users to provide a viewable picture from a scrambled video signal, comprising:

• means receiving the scrambled video signal for generating a black box jamming signal having improper vertical rate signal characteristics;
• and
• means responsive to the generating means for superimposing the jamming signal on the scrambled video signal generally in blanking intervals thereof to produce unstable vertical rate signals which cause an unviewable video signal;
• wherein:
• the generating means include a timing circuit for providing timing signals indicative of the vertical blanking interval and vicinity;
• and
• circuit means for generating the jamming signal selectively and generally in the vertical blanking intervals;
• and
• the superimposing means include inserter circuit means responsive to the timing circuit for adding the jamming signal to the scrambled video signal at the selected times generally in the vertical blanking intervals.

Method of defeating an illegal black box used to overcome the scrambling effect of a scrambled video signal thereby presenting an unviewable picture to an unauthorized user of the black box comprising:

• generating a jamming signal of unreliable vertical rate signal characteristics;
• and
• superimposing or inserting the jamming onto the scrambled video signal during a time duration which at least encompasses vertical blanking intervals of the video signal to cause the illegal black box to generate unstable vertical rate signals and thus the unviewable video signal,
• wherein:
• the jamming signal includes a fake vertical signal having gap signals in conjunct on with an amplitude modulated fake broad pulse signal;
• and
• the step of superimposing or inserting includes:
• adding the fake vertical signal to the scrambled video signal in selected video lines in the vertical blanking interval.

Method of defeating an illegal black box used to overcome the scrambling effect of a scrambled video signal thereby presenting an unviewable picture to an unauthorized user of the black box comprising:

• generating a jamming signal of unreliable vertical rate signal characteristics;
• superimposing or inserting the jamming signal onto the scrambled video signal during a time duration which at least encompasses vertical blanking intervals of the video signal to cause the illegal black box to generate unstable vertical rate signals and thus the unviewable video signal;
• generating the jamming signal as averaged bottom picture luminance values before the vertical blanking interval and top picture luminance values at the end of the vertical blanking interval;
• interpolating the luminance values during the vertical blanking interval;
• and
• dithering the interpolated luminance values via a varying voltage ranging generally from blanking level to peak white level.