| 摘要 |
An input automatic switching circuit for monitor is provided to solve troubles that may occur by manipulation with hands. This circuit switching R, G, B, H and V signals applied through a BNC input terminal or D-SUB input terminal and outputting to a video/synchronous signal detecting part (1), includes a horizontal synchronizing separating part (2) separating a horizontal synchronous signal from applied horizontal, vertical composite synchronous signals synthesized by a video signal, green; a differential circuit (3) performing a differentiation with respect to the horizontal synchronous signal; a high-pass filter (4); a monostable multi-vibrating circuit (5) triggered by a signal applied via the differential circuit (3) or the high-pass filter (4) and vibrating by an oscillating time constant; an input switching part (6) driving a switching relay (RY1) in response to the monostable multivibrating circuit (5)'s output; and a relay switch (RL1) switching in response to the part (6)'s relay driving and selecting one of signals applied via a BNC or D-SUB input terminal. |
