| 摘要 |
PURPOSE:To prevent the deterioration of quality of reproduced pictures due to abnormal hue reproducing by discriminating the special reproducing mode when no serrated pulses exists and operating a chroma killer circuit then to reproduce white and black pictures. CONSTITUTION:The video signal inputted to a synchronous signal separating circuit 1 is synchronously separated, and the output is inputted to a horizontal deflecting circuit 5, a vertical deflecting circuit 6, and a serrated pulse detecting circuit 2. Outputs of the horizontal deflecting circuit 5 and the vertical deflecting circuit 6 are supplied as deflecting signals to a horizontal deflecting yoke and a vertical deflecting yoke of an EVF-CRT 7. The serrated pulse detecting circuit 2 detects whether a serrated pulse exists in the vertical synchronous period of a video signal A or not, and the circuit 2 outputs an operation signal B to a chroma killer circuit 3 if its is absence (dropped out). The chroma killer circuit 3 controls a chroma amplifier 4 to narrow down the degree of color saturation, and the output of the chroma amplifier 4 is amplified by a video signal circuit 8 and is supplied to the EVR-CRT 7 to reproduce white and black pictures. |
