| 摘要 |
PROBLEM TO BE SOLVED: To properly perform a horizontal synchronization detection to a horizontal synchronization signal whose period is not known. SOLUTION: A pulse detecting portion 110 detects a pulse in a horizontal synchronization signal SB, and acquires a generation period and a pulse width of the detected pulse. A synchronization pulse determining portion 120 determines a pulse which satisfies that a generation period is within an error permissible range of a reference period and a pulse width is within the error permissible range of a reference pulse width as a synchronization pulse. An average period acquisition portion 150 averages the generation period of the synchronization pulse to obtain an average period. A reference period correcting portion 130 performs both or either one of corrections of a reference period so as to approach the average period and of the error permissible range of the reference period so as to narrow on the condition that a generation frequency of the synchronization pulse whose error between the generation period and the average period exceeds a predetermined permissible range exceeds a predetermined threshold. COPYRIGHT: (C)2009,JPO&INPIT
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