Abstract: The passive interdiction system for CATV scrambling provides a plurality of passive, preselected negative signal traps for securing specific CATV channels. Each trap cyclically attenuates the desired CATV channel thereby confusing the AGC (automatic gain control) circuit of the television monitor-receiver or video cassette recorder (VCR) by rapid cancellation and restoration of the picture carrier and main signal components. The passive interdiction system is comprised of a plurality of SAW (surface acoustic wave) resonators tuned to specific frequencies corresponding to the carrier frequencies of the channels to be secured and are alternately keyed on and off by a 10 to 20 Hz square wave. Authorization and control of the secured channels originates at the cable provider's headend and is transmitted contemporaneously with the CATV programming. The authorization data is specifically addressed and decoded at unique interdiction units disposed within the CATV system.

Abstract: An encrypted video distribution system includes a signal originating station which distributes television signals in a format unrecoverable by a standard television receiver. In particular, the normally occurring vertical and horizontal synchronizing pulses are deleted and, optionally also, video information is selectively inverted about a voltage reference potential intermediate the black and white levels. To permit synchronization restoration, a keying pulse is transmitted once each video field, and a synchronizing digital code burst transmitted once each frame--all at a fixed, predetermined intra-frame timed relationship. At each authorized subscriber location, the keying pulse and digital code burst are employed to lock a receiver frame clock which derivatively gives rise to all requisite reception-permitting synchronizing pulses. The transmitted information also contains information sufficient to restore the inverted video program content.

Abstract: An improved system arrangement for distributing and permitting use of an ensemble of program controlled television games includes head end apparatus for impressing an array of game-regulating programs onto an electronic distribution system, e.g., by time division multiplexing into an assigned frequency band on a television program distributing CATV or MATV cable. At any of plural receiver locations connected to the distribution channel, a user desiring a game selects ("tunes") the game frequency band and loads a game program memory (RAM) with the program for the particular game desired. The composite apparatus then functions in the now per se conventional manner to actually implement the selected game in conjunction with a television receiver and player control(s).