Circuit and method for position compensation for a main image

摘要

The compensation circuit comprises a sub-image IF processor for separating a sub-image video signal and a sub-image synchronisation signal from an IF signal of an input sub-image, a sub-image video processor for reducing the image format of the sub-image video signal from the sub-image IF processor, an OSD signal generator for generating OSD colour signals in dependence on a first control signal, a microcomputer for generating the first control signal, a second control signal and control data in dependence on a key input signal, a hue circuit for switching an external main-image video signal, the sub-image video signal from the sub-image video processor and the OSD colour signals from the OSD signal generator for outputting a video signal for a composite image, a deflection control device for generating horizontal and vertical deflection control currents in dependence on main-image horizontal and vertical synchronisation signals input for controlling the beam scanning direction of a colour picture tube, a memory for storing sub-image delay data and OSD range delay data and a horizontal synchronisation signal switching device for delaying the main-image horizontal synchronisation signal in dependence on the second control signal from the microcomputer. <IMAGE>