| 摘要 |
PURPOSE: To provide a display controller for image display device with which stable display control can be performed while speedily responding to the change of a synchronizing signal. CONSTITUTION: Concerning a display controller 1 for image display device provided with a horizontal control system and a vertical control system, a horizontal extract signal HSD corresponding to a horizontal synchronizing signal H accompanying the phase deviation of a video tape recorder is extracted by a horizontal extraction circuit 19, the phase of a horizontal monitor signal WIN corresponding to a horizontal control signal from the horizontal control system is compared with the phase of the horizontal extract signal HSD by a comparator 20, and phase comparison information is outputted. Based on the phase comparison information due to the comparator 20, a switching judging circuit 21 switches the frequency dividing ratio of the horizontal control system, a phase locked loop system is controlled, and the horizontal control signal is synchronized with the horizontal synchronizing signal H accompanied by the phase deviation. |
