| 摘要 |
PURPOSE:To obtain a digital correction circuit which performs the correction of screen distortion or shift of convergence even when a power source is applied or a deflecting frequency is changed by calculating correction data on each scanning line between two correction points in sequence of differential value with high priority. CONSTITUTION:An arithmetic circuit 4 reads out the correction data on the two correction points neighboring in a perpendicular direction from nonvolatile memory 20, and calculates the differential value of the data. A number is attached on the data in sequence of higher differential value by comparing the differential values, and it is stored in the nonvolatile memory 20 of memory 2. Thence, when the power source is applied or a horizontal deflecting frequency is changed, the correction data on upper and lover correction points in the perpendicular direction stored in the nonvolatile memory 20 of the memory 2 are read out according to the order of an address stored in the nonvolatile memory 20 of the memory 2. The correction data on each scanning line located between the two correction points can be calculated from those data. Therefore, the correction data on the scanning line found after an image is changed can be made small, which prevents it from being prominent on the image. |
