Digitally controlled vertical S linearity correction with constant amplitude without using an AGC

摘要

A digitally-controlled vertical S linearity correction with a constant amplitude without using an AGC. To preserve line spacing between horizontal lines toward a top and bottom of a screen a third order correction voltage V_cube is applied to a sweep voltage V_osc. A constant current decoder determines an amount of appropriate correction current, which is employed to generate a sweep voltage with modified amplitude due to S correction and one without the modified amplitude. The sweep voltage with constant amplitude is employed to generate V_cube. V_cube is then applied to the sweep voltage along with a compensated amplitude component of the sweep voltage, such that a reduction in the amplitude caused by the S correction is compensated in the output voltage V_out. The compensation of the output voltage amplitude prevents a size reduction of the displayed picture on the screen without employing an iterative auto-align process.