| 摘要 |
PURPOSE:To perform stable tracking in a servo system requiring DC gains by comparing the 1st, 2nd sample holding circuits and turning a tracking mirror always in the direction where the smaller sample value is taken in. CONSTITUTION:The respecive sample values 18a, 18b of sample holding circuits 15a, 15b are compared in a comparator 29, and the analog switch 31a or 31b on the side where the smaller sample value is taken in is turned on by the output signal 30 thereof. More specifically, if 18a<18b, the switch 31a goes on and the sample value 18a is fed to the next circuit. If 18a>18b, the switch 31b goes on and the sample value 18b is inverted by an inversion amplifier 32 and is fed to the next circuit. These signals are added in an adder 33, the output thereof is supplied via an offset removing circuit 34 and a low-pass filter 20 to a driving circuit 21. |
