An image display comprises a refractive optical lens (15) for directing light from transmitting means to a convex mirror (16) and correcting the pincushion distortion aberration of the convex mirror (16).
The circuits of the television receiver are fed with supply voltages which are stabilized through a mains supply unit and the pillow distortion of the 110° picture tube is adjusted by means of active east-west screen correction.
In addition, other television alignment parameters such as upper and lower pin cushion, vertical bow, pin amplitude and/or horizontal angle may be determined.
The control circuit may also provide a raster width compensation voltage for an east-west pincushion correction circuit.
A circuit (410) for providing an output voltage (VP) to a pincushion modulator circuit.
A compensation path (Cf) eliminates instability at frequecies above a first frequency caused by interaction between the amplifier and the pincushion modulator circuit.
The amplifier amplifies the input signal to produce the output voltage at an output of the amplifier which is coupled to an input (520) of the pincushion modulator circuit.
The first capacitor is coupled to an East-West pincushion raster correction current source (301) for producing a second ramping capacitor voltage in the first capacitor that ramps in an opposite direction.