| 摘要 |
PURPOSE:To make the zero adjustment of the entire instrument by separately removing a zero-point variation component generated by a measuring circuit system and that by an optical system. CONSTITUTION:To make a zero adjustment, switches SW1-SW4 are placed at the side of standard signal generating circuit 29. Through switch SW1, the 1st standard signal s0 and standard light false signal are input to differential amplifier 24. Simultaneously, the 4th standard signal c0 is applied to the gate of FET via switch SW2 and capacitor C2 is charged by the 1st standard signal S0. The output of differential amplifier 24 is applied to gate circuits 25 and 26 and at the same time, switches SW3 and SW4 are changed over to apply the 2nd and 3rd standard signals a0 and b0 to gate circuits 25 and 26, which are alternatively reset. Then, the zero adjustment is made by adjusting logarithmic converting circuit 27 so that the output voltage of output terminal 28 will be zero. |
