Abstract: Methods and apparatus for scrambling and unscrambling a plurality of data streams having differing data, on a plurality of signal channels, are taught. The data streams may be television programs or other signal information, transmitted in a frame-by-frame manner with discrete synchronizing information, and where some of the data streams may be high priority such as pay-TV program material. All of the data streams are synchronized, an encryption key code is imposed on them, and a data package containing an identifier code for each data stream and a routing code is generated, so that each data stream is assigned at any instant of time to a specific one of the plurality of signal channels. The data package is encrypted in each data stream by being inserted at a specific place therein relative to the synchronizing information.

Abstract: A memory and driver circuit for each lamp of a flat screen video display apparatus which comprises a plurality of addressable incandescent lamps arranged in an X-Y matrix is provided. The gray scale visual effect of the video information being presented comes as a result of controlling the length of time of illumination of each lamp. Each of the lamps is connected in series with a source of power and a switchable solid state device such as an SCR or a transistor. When the source of power is an alternating current source where each of the pulses has its initial slope always in the same sense with respect to zero, the circuit is arranged with negative-going video information so that the lamps are held off -- i.e., black -- in the presence of a video signal above a threshold, and are thereafter turned on. Phase modulation is thereby provided. When the source of power is direct current, each lamp is illuminated when there is a video signal intended for that lamp and above a predetermined reference level.