Abstract: A television synchronization system in which a bipolar signal having a waveform including a front porch (304), a negative polarity pulse, a positive polarity pulse and a back porch is used as a horizontal sync signal, and a composite signal having a waveform including the positive polarity pulse, the back porch, a negative polarity pulse with a wide pulse width, a front porch and a negative polarity pulse is used as a vertical sync signal. When separating and reproducing the sync signals from a television signal transmitted through a transmission line, deviation of the reference phase can be eliminated so that the accuracy of the reproduced phase is improved. Therefore, the television synchronization system is preferably used in a high definition television system.

Abstract: A projection type image display device utilizing an oil film is disclosed, which device comprises a filter having frequency characteristics enabling reduction of the spatial frequency response in the vertical direction for an input signal having a stepwise waveform in the vertical direction to a value under those obtained by using the following formula with respect to the coordinate x of the position of the scanning line in the vertical direction;f(x)=[1+sin (.pi..multidot.x/D.sub.O)]/2where D.sub.O represents the smallest scanning line interval, outside of which adjacent scanning lines have no influences thereon, and filtering the input image signal according to those characteristics.