| 摘要 |
PURPOSE:To effectively remove synchronizing signals, by clamping comosite video signals input through an input circuit, comparing the clamped composite video signal with the clamp level, and then, by returning the comparison output to the above mentioned input circuit. CONSTITUTION:Composite video signals are input into a clamp circuit composed of a transistor 31, diode 36, etc., from a terminal (e). Then, the clamped composite video signals are input into a differential amplifying circuit composed of transistors 38, 39, 40, etc. On the other hand, synchronizing signals are input into a terminal (g), and the transistor 40 is turned on and the differential amplifying ciruit operates only during the period of positive synchronizing signals. Video signals from which synchronizing signals are removed in this way, are fetched from the base of the transistor 38. |
