Abstract: A video display apparatus includes a diode modulator for correcting side pincushion raster distortion. The diode modulator drive circuit produces a vertical deflection rate parabolic voltage that modulates the horizontal deflection current to effect pincushion correction. The drive circuit includes a transistor that has its base bias established by the combination of a width control resistor and a diode. The diode has the same thermal characteristics as the transistor to provide accurate temperature compensation. A resistor is connected between the emitter of the transistor and a supply voltage to change the transistor bias point in order to enable the transistor to be cutoff.