| 摘要 |
PURPOSE:To generate a precise correction waveform and supply the stable correction waveform by calculating a saw-tooth wave and a sine wave waveform consisting of a combination of two kinds of secondary curves for correction and putting them together. CONSTITUTION:A microprocessor 11 digitally calculates a generated waveform and stores the result in a memory 17. When the waveform stored in the memory 17 is read out, the waveform is read out of the memory 17 in order by using the value of a counter 15 as an address and converted by a D/A converter 18 into an analog waveform, which is sent out as a waveform for deflection of a CRT. When (n) addresses are used, the counter value varies repeatedly between 0 and n-1. To generate the waveform, the secondary curves in sine wave shapes are found by using the saw-tooth wave for deflection and a variable based upon the time base of the saw-tooth wave and the arithmetic results are put together to generate the desired correction waveform for correcting the density of screen end parts and the center part. The correction wave is varied in amplitude and then easily approximated to the desired correction waveform. |
