| 摘要 |
PURPOSE:To enable to perform correct and moreover high speed gain control of a positioning device by a method wherein a means to regulate properly the level of a light signal to be obtained according to second scanning for second positional detection is provided utilizing light volume informations obtained according to first light scanning for first positional detection. CONSTITUTION:Video signals sent from a television camera control part B are integrated by an integrator 501 consisting of an operational amplifier and a capacitor. The integrated light volume corresponding to the amount of one field is digitized by an A/D converter 503 of 8 bits to be sent to a control circuit F, a microprocessor for example, and a control signal is sent to a gain change-over circuit 99 in a fine alignment detection circuit E according to light volume data thereof. While the voltage of a light signal for fine alignment inputted through an analog switch 102 is divided according to the resistor group R1-R9 of the gain change-over circuit, while only one necessary voltage-divided signal of the signals thereof is selected according to the control signal to be outputted from a data selector (d). |
