| 摘要 |
PURPOSE:To compensate the change of the terrestrial magnetism and to prevent the color purity from being damaged by making the direction and the magnitude of the current flowing to a terrestrial magnetism compensating coil changeable by using a remote controller. CONSTITUTION:A remote control signal is received by a light reception part 1 and is converted to an electric signal, and a control part 2 outputs a control signal corresponding to this electric signal and inputs it to one end of a switch circuit 5. The switch circuit 5 switches the polarity of the DC output applied to a terrestrial magnetism compensating coil 6 attached to the periphery of a CRT 7 to change the direction of the current flowing to this coil 6. A D/A converter 3 converts the control signal from the control part 2 to an analog signal and changes the level to output it as a DC. An amplifier 4 amplifies it to a proper magnitude to input it to the other end of the switch circuit 5. The switch circuit 5 changes the DC level applied to the terrestrial magnetism compensating coil 6 to change the magnitude of the current flowing to the terrestrial magnetism compensating coil 6, thus correcting the deviation of color purity. |
