Abstract: A combined analog and digital video television signal switching system is provided in which parallel video signal paths are provided for analog and digital television signals, these paths being controlled by common control signals.When a video input signal is digital it is supplied to the digital signal path and an analog zero reference signal is supplied to the corresponding analog input in the analog signal path. When a video input signal is analog it is supplied to the analog signal path and a digital zero reference signal is supplied to the corresponding digital input in the digital signal path.The analog mixers in the analog signal path and the digital mixers in the digital signal path are each controlled by the same control signals generated by the common control equipment.

Abstract: A television special effects system is provided wherein digitized picture elements of any one of a plurality of video input signals are assigned addresses corresponding to the desired location of each picture element in a composite output image. The digitized picture elements are then stored in a memory having a capacity equal to one full TV frame in accordance with the addresses assigned thereto.Each video input may be positioned at any location in the composite output image by adding to or subtracting from the write addresses by means of horizontal or vertical positioning numbers. Each video input may also be compressed in either the horizontal or vertical direction, or both, by means of horizontal or vertical compression factors which control the write address generating means so that certain picture elements of the video input are not stored in memory.

Abstract: An analog video special effects generator capable of producing unusual special effects such as a five-pointed star, a heart, a keyhole and a binocular shaped pattern in addition to standard patterns such as horizontal and vertical wipes. The special effects are achieved by utilizing ramp generators to generate bi-directional ramp signals and modulus circuits for taking the absolute values of the ramp signals in order to generate complex waveforms. Switching and combining circuits are utilized to combine the complex waveforms from various ones of the modulus circuits to generate the switching waveforms necessary to produce the unusual patterns.