VERTICAL DEFLECTION CIRCUIT AND VIDEO DISPLAY DEVICE HAVING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a vertical deflection circuit and a video display device without adding a circuit to shorten the retrace time more than before and capable of positioning a bright line for reference on an optimum point even in the case of signals whose validity in the vertical direction is large. SOLUTION: The vertical deflection circuit which can display the bright line for reference to automatically adjust a black level by a reference pulse is provided with a vertical saw-tooth wave generating circuit 6 to generate the saw-tooth wave of a vertical period and a retrace point setting means 4 to set a retrace point for starting up the saw-tooth wave generated by the vertical saw-tooth wave generating circuit 6 at a prescribed time prior to a vertical synchronizing signal Vs and to begin the retracing in prior to the vertical synchronizing signal. The vertical deflection circuit superposes a reference pulse on a video signal in timing of the retracing period of the saw-tooth wave based on the retrace point set by the retrace point setting means 4.