| 摘要 |
PURPOSE:To obtain a focusing device that follows quickly the movement of a subject by shifting the position of image formation of the subject according to a focusing signal or a distance signal of the subject. CONSTITUTION:A video signal outputted from the image pickup plane 4 of an image pickup tube 3 driven by a synchronizing signal circuit 1 and an image pickup tube driving circuit 2 are resolved into a luminance signal Y, red color signal R and blue color signal B through a pre-amplifier 6, an LPF 7, a BPF 8 and a color separation circuit 9. These signals are mixed by a matrix circuit 10. Color difference signals R-Y, B-Y are modulated in modulators 11, 12 by a signal transferred 90 deg. from a synchronizing signal generating circuit 1 and color signals added by an adder 13 are added to a signal Y and attains a video signal S. On the other hand, an arithmetic circuit 17 receives the Y signal and sends a focusing signal F to the image pickup tube driving device 18, and moves the image pickup tube to a proper focusing position and follows the movement of the subject 5 quickly. |
