Left and right raster correction.

摘要

The video display includes a CRT with a deflection coil for raster generation. A deflection amplifier is coupled to the deflection coil. A correction waveform modulator is coupled to the deflection amplifier to generate a corrective current in the deflection coil. There is an auxiliary coil mounted on the CRT for raster correction. An auxiliary coil drive amplifier coupled to the auxiliary coil generates a second corrective current in the auxiliary coil. The first corrective signal from the waveform modulator and the second corrective signal, supplied to the auxiliary coil, generate raster correction respectively at opposite raster edges. Pref. the first corrective signal is a vertical rate ramp shaped signal for trapezoidal correction at one first display edge, e.g. a vertical rate parabolically shaped signal for pincushion correction at the display edge, and the second corrective signal is a vertical rate parabolically shaped signal for pincushion correction at the opposite edge.