A vertical and optical distortion correction apparatus in a projection television set is provided. Thermal consumption of each convergence output end is reduced, convergence control is facilitated and a correction control time is shortened by correcting the optical and vertical distortions at each vertical output end of red, green and blue cathode ray tubes.

A horizontal size adjusting apparatus of a monitor capable of varying size and linearity of a deflection signal by varying an amount of current supplied to a deflection circuit in accordance with a horizontal frequency includes a first current controlling section for generating a plurality of first control signals to vary the amount of current supplied to the deflection circuit and adjusting a horizontal size by correcting the size and linearity of the deflection signal in accordance with first control signals, a second current controlling section for generating second control signals to vary the amount of current supplied to the deflection circuit by receiving output signals of a decoder and adjusting the horizontal size by correcting the size and linearity of the deflection signal in accordance with the second control signals, and a current output section for supplying the amount of current varied by the first and second current controlling sections to the deflection circuit. By varying the size and linearity of the deflection signal in accordance with the output current of the current output section, the horizontal size is accurately adjusted while improving picture quality.

A circuit for providing an output voltage to a pincushion modulator circuit. The circuit includes an amplifier having an input for receiving an input signal. The amplifier amplifies the input signal to produce the output voltage at an output of the amplifier which is coupled to an input of the pincushion modulator circuit. A compensation path eliminates instability at frequencies above a first frequency caused by interaction between the amplifier and the pincushion modulator circuit.

An electron beam tends to slope downwardly as it is deflected horizontally to form a raster in a video display apparatus. The sloping of the beam can cause geometric errors in the raster, for example, orthogonality and parallelogram errors. A raster correction circuit offsets orthogonality and parallelogram errors in a raster by modulating a horizontal deflection current at a vertical scanning rate. The raster correction current is phased in relation to a horizontal-rate deflection current such that scan lines in an upper-half portion of the raster are shifted to the right, and scan lines in a lower-half portion of the raster are shifted to the left.

A secondary winding of a horizontal flyback transformer of a horizontal deflection circuit develops a horizontal retrace pulse voltage. A secondary winding of a second transformer is coupled in series with a vertical deflection coil of a vertical deflection circuit. An R-C filter is coupled between the secondary winding of the flyback transformer and a primary winding of the second transformer. Horizontal parallelogram errors are corrected by a horizontal rate current injected in a current path of the vertical deflection coils. The R-C filter prevents the vertical deflection current from being parasiticaly coupled to the horizontal deflection circuit.