DEGAUSSING APPARATUS FOR EARTH MAGNETIC FIELD

摘要

PURPOSE: An automatic earth magnetic field deflection correcting apparatus is provided to correct a screen distortion and a color spread of a display device using an earth magnetic field sensor which automatically checks an earth magnetic field. CONSTITUTION: An earth magnetic field sensor(200) senses and outputs an earth magnetic field according to an earth magnetic field output control signal. A frequency generator(210) generates a frequency corresponding to the earth magnetic field sensed by the earth magnetic field sensor(200). A counter(220) counts the frequency from the frequency generator(210) by a predetermined number and generates a gate signal. A microcomputer(230) compares the gate signal from the counter(220) with a reference signal to output a value which an earth magnetic field is corrected and outputs a control signal for controlling an output status of the earth magnetic field sensor(200). A horizontal processor(240) corrects an earth magnetic field deflection of a cathode ray tube according to a corrected value from the microcomputer(230).