SYNCHRONIZING SEPARATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To prevent an OSD output character from vertically rocking by improving the stability of a vertical synchronization detection operation to noise in a synchronizing separation system for separately detecting a horizontal synchronizing signal and a vertical synchronizing signal from a composite video signal. SOLUTION: When comparators 13 and 14 perform level discrimination of a composite synchronizing signal Pin obtained by selectively amplifying the composite video signal Sin while performing phase inversion of the composite video signal Sin and pulsing the composite synchronizing signal Pin, threshold value levels Vth1 and Vth2 used in the pulsing are separately set in a non- equivalence pulse period and in an equivalence pulse period.