SYNCHRONIZING SIGNAL PROCESSING CIRCUIT, IMAGE PROCESSING APPARATUS USING IT AND SYNCHRONIZING SIGNAL DISCRIMINATION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a synchronizing signal processing circuit that can ensure field discrimination without error and imposing any restriction onto a processing signal and to provide an image processing apparatus using the same and a synchronizing signal discrimination method. SOLUTION: The synchronizing signal processing circuit is provided with a field discrimination circuit 13 that extends a pulse width of a horizontal synchronizing signal H-SYNC supplied from a synchronizing separator circuit 12 to a prescribed width at e.g. 1/2 H or below to generate a horizontal synchronizing signal H-SYNCW whose pulse width is extended. The circuit is also provided with an interface circuit 15 that detects whether the horizontal synchronizing signal H-SYNCW whose pulse width is extended is at a high level or at a low level at a prescribed position of the 1/2 H or below of the horizontal synchronizing signal supplied from the field discrimination circuit 13 on the basis of a front edge of a vertical synchronizing signal V-SYNC and discriminates whether a field of a video signal is an odd number field or an even number field.