| 摘要 |
PURPOSE:To prevent a picture from getting distorted by making use of a modified saw-tooth wave as a horizontal scanning signal for a video device such as an infrared-ray video device equipped with a light deflector rotating in both the directions. CONSTITUTION:A horizontal scanning signal generated from block 8 and a vertical scanning signal from block 9 are applied to CRT for sweep operation. The waveform of this horizontal scanning signal is changed, at the mixing ratio between saw- tooth wave A and sine wave B, into waveform C that has the greatest gradient in the middle between the scanning start point and ending point and decreases in gradient at a farther point. When the modified saw-tooth wave like this is used, the moving speed of a spot on the CRT screen is made high in the center and low at the circumference of the edge part. As a result, the spot moving speed on CRT that corresponds to the same rotation angle of a plane mirror is made even over the entire surface and the distortion of a picture is prevented. |
