CIRCUIT GENERATEUR DE TENSION PARABOLIQUE POUR APPAREIL DE VISUALISATION

A vertical rate parabolic voltage at a peak-to-peak amplitude that is adjustable is generated in an integrator from a sawtooth input voltage. The parabolic voltage at an output terminal of the integrator is applied to a source of a B+ operating voltage to form a parabolic component voltage of the B+ operating voltage that controls the amplitude of a trace current in a horizontal deflection circuit output stage. The parabolic voltage is adjusted in peak-to-peak amplitude to provide east-west pincushion correction of the raster. The minimum level of the parabolic voltage in each vertical period is automatically maintained at an unchanged level that is approximately zero volts throughout the range of east-west adjustment. Because the minimum level of the parabolic voltage remains unchanged, the maximum level of the B+ operating voltage, a level that occurs in the center of each vertical interval, also remains unchanged throughout the range of east-west adjustment. In this way, the width of the raster is unaffected by adjustment of the peak-to-peak amplitude of the parabolic component voltage of the B+ operating voltage.