Tektronix, Inc.

Steven F Liepe

Pierre A Radochonski

Glenn R Johnson

A voltage regulator for an anode voltage supply in a CRT powered by a deflection flyback pulse generator includes a voltage sensing network for providing a feedback signal to a summing amplifier. A pulse sensing network which may be a capacitive divider is connected between the output of the flyback pulse generator and the input to the summing amplifier. The resultant output of the summing amplifier is the flyback pulse level shifted with respect to a DC level which is applied to a MOSFET switch to turn it on whenever the flyback pulse goes above the MOSFET's threshold. The output of the MOSFET switches current through a shunt capacitor coupled to the output of the deflection flyback pulse generator for altering its capacitance thereby regulating the height of the flyback pulses, and thus regulating the anode voltage supply.

High voltage regulator for CRT anode voltage supply

A degaussing system for a CRT includes a voltage source, which is enabled by power-up of the CRT, coupled to a tank circuit including a degaussing coil and a capacitor. A voltage sensing network connected in parallel with the tank circuit senses the voltage across the capacitor and when that voltage rises to a predetermined threshold, and actuating signal is provided which turns on a latching switch circuit which enables a switch connecting the tank circuit to ground. This allows it to oscillate, taking the metal components of the CRT through a decreasing series of hysteresis loops as the oscillation decays. The latching switch circuit maintains the switch in an on position until power-down of the CRT, thus maintaining all except R1 which aids grid regulation of the components of the degaussing system, in a low voltage state until degaussing becomes necessary once again.

Automatic high-speed color CRT degaussing system

A scheme for digitizing a stationary video image is disclosed. The amplitude of a video signal, representing said video image, is sampled at a plurality of points along the time axis and is compared with the count in a counter. If the amplitude equals the count at a particular point on the time axis, the count is stored in a memory in a location corresponding to said particular point. The process is repeated until a count in the counter is stored in said memory in locations corresponding to all of said plurality of points along the time axis of said video signal. If two or more counters are used, each counting from a different initial value, and if two or more corresponding comparators are used to make the above comparison, the time required to digitize said stationary video image may be reduced. Consequently, the time required for the video image to remain stationary is reduced.

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Tualatin, OR, United States of America

Steven F Liepe