Abstract: Apparatus for interdicting television channels of a cable television system comprises a plurality of oscillators dedicated to jamming the audio portion of television channels to be interdicted, and a further plurality of different oscillators dedicated to jamming the video portion of television channels to be interdicted. The number of jamming oscillators for jamming the audio is less than or equal to the number of jamming oscillators for jamming the video. The hopping rate for video jamming is greatly in excess of the hopping rate for audio jamming. On the other hand, the dwell time for audio jamming is greatly in excess of the dwell time for video jamming. At least two levels of jamming effectiveness of both audio and video portions can be addressably controlled from the headend of a system including such interdiction apparatus.

Abstract: A system for reducing bandwidth of video signals. Ordinarily, an NTSC (National Television Standards Committee) video signal has (a) a bandwidth of 6.0 MHz, (b) chrominance and luminance carriers separated by about 3.58 MHz, and (c) an audio carrier located at the upper end of the 6.0 MHz bandwidth. The invention reduces the separation between chrominance and luminance carriers to about 2.15 MHz, and decreases the bandwidth to about 4.0 MHz. In addition, the invention moves the audio carrier outside the 4.0-MHz bandwidth. The invention allows multiple channels, of 4.0 MHz bandwidth each, to be placed adjacent each other in a cable television spectrum, and the audio signals of the channels to be placed together, at the upper end of the spectrum, outside the range allocated to the video information. A larger number of channels is obtained than would otherwise be available, because the upper end of the spectrum is not suitable for carrying video information, but will handle audio information.