| 摘要 |
PURPOSE:To generate a stable reference signal in synchronizing with a vertical and a horizontal signal by utilizing an equivalent pulse arrived after a prescribed period of a tail ridge part of the vertical synchronizing signal as the reference signal of the vertical signal. CONSTITUTION:A pulse signal Sh having the same phase as that of the equivalent pulse EQ is obtained at an output terminal of a count circuit 38 by providing the count circuit 38 having the capacity for counting a clock signal S1 up to the preset final count value for the first time when the equivalent pulse EQ is outputted from a horizontal synchronizing signal separating circuit 37. The phase of a signal Si obtained from the equivalent pulse EQ in this signal Sh and the phase of a signal Sj obtained from a memory 41 according to the count operation of a count circuit 22 are compared to shift the reset timing of the count circuit 22. Thus, this operation is repeated for several vertical scanning periods, resulting that the horizontal and vertical reference signals are synchronized with the horizontal and vertical synchronizing signals. |
