IMAGE SUPERPOSING DEVICE

PROBLEM TO BE SOLVED: To provide a video superimposing device which can supply picture quality without distortion. SOLUTION: The video superimposing device is provided with a synchronization separator 10 separating an external composite synchronizing signal from an external composite video signal, a clock signal generator 20 generating a clock signal so that it is synchronized with the external synchronizing signal with a phase difference between the horizontal synchronizing signal of the separated external composite synchronizing signal and an internal composite synchronizing signal, a synchronizing signal generator 30 inputting the clock signal and generating the internal composite synchronizing signal and a refresh address signal, a video memory part 40 reading digital video information stored in accordance with the refresh address signal and writing digital video information in accordance with a write address signal and a superimposing part 50 restoring digital video information which is read from the video memory 40 as RGB signals, encoding the inner composite synchronizing signal and the restored RGB signals as color television signals, superimposing them with the outer composite video signal and outputting a video signal are provided.