Abstract: There is disclosed a compatible television receiver capable of receiving and reproducing both the standard system television signal and the high definition television signal and capable of confining the degradation of picture quality of the high definition television signal to the minimum, in which the received standard system television signal and high definition television signal are respectively converted to non-interlace signals, and scanning is selectively performed with either of non-interlace video signals to display images.

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.