Ncr Corporation

Robert G Mankedick

Lawrence C Barnes

Syed Naseem

An apparatus and its method having a first input for receiving a video signal, and a second input for receiving a computer generated graphics signal. A proportioning circuit is included which algebraically adds a portion of the signal from one input, and an inversely proportional portion of the signal from the other input. The algebraically added signal portions are provided for video display. The apparatus may include a voltage limiting circuit for limiting the combined voltage of the added signal portions to less than a set level.

Apparatus and method for mixing video signals for simultaneous

Liquid crystal displays having improved apparent viewing cones are disclosed. The displays are activated by an electrical energizing signal which comprises an activation signal portion and a superimposed A.C. voltage signal by which the apparent viewing cone angles of the displays are increased.

Liquid crystal displays and method by which improved apparent viewing

An apparatus, and its method, for overlaying a computer display on a video signal, having a video signal receiving circuit, a sync strip circuit connected to said video signal receiving circuit for stripping the sync pulses from the video signal, and a display control circuit for generating display control pulses. A phase locked loop circuit is provided for locking the display control pulses in phase with sync pulses stripped from the video signal when the video signal is present, and for controlling the display control means to generate display control pulses at a selected rate when the video signal is absent. A vertical drive pulse generating circuit generates vertical drive pulses in phase with selected ones of the sync pulses stripped from the video signal when the video signal is present, and generates vertical drive pulses after a set number of generated display control pulses when the video signal is absent. A computer display generator circuit generates computer display signals under the control of the display control pulses and the vertical drive pulses. A combining circuit combines the video signal with the generated computer display signals when the video signal is present, and blocks the subsequent combining of later received video signals with the generated computer display signals for a set time when the video signal is absent, allowing the phase locked loop circuit to lock the display control pulses in phase with the sync pulses of the reestablished, later received video signals.

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Longwood, FL, United States of America

Robert G Mankedick