公开(公告)号：US3801919A

公开(公告)日：1974-04-02

申请号：US3801919D

申请日：1972-10-30

Applicant: MANDREL INDUSTRIES

Inventor： WILKES D ,  THOMPSON C

IPC: H03F1/30 ,  H03F1/26

CPC classification number: H03F1/303 ,  H03F2200/372

Abstract: A feedback null loop includes a low drift, first loop amplifier connected to the output of a fast settling, large drift amplifier means which is to be corrected for AC and DC errors due to stray signal coupling. A second loop amplifier with high impedance is coupled to the low drift first loop amplifier via electronic switch means. A ground line is provided to the input of the large drift amplifier means; e.g., via the conventional multiplexer apparatus in a multi-channel data acquisition system, whereby the output voltage of the amplifier means is nulled to zero. Prior to opening the switch means in the null loop, a capacitor stores a fixed voltage representing the error signal. Thereafter, as the multiplexer apparatus selects successive channels of the data acquisition system, any DC off-set levels are balanced out via the temporarily stored capacitor voltage.

Abstract translation: 反馈空回路包括连接到快速稳定的大漂移放大器装置的输出的低漂移，第一环路放大器，由于杂散信号耦合而被校正的AC和DC误差。 具有高阻抗的第二环路放大器通过电子开关装置耦合到低漂移第一环路放大器。 地线被提供给大型漂移放大器装置的输入端; 例如通过多通道数据采集系统中的常规多路复用器装置，由此放大器装置的输出电压为零。 在零开环之前打开开关装置，电容器存储表示误差信号的固定电压。 此后，随着多路复用器选择数据采集系统的连续通道，任何直流偏移电平都通过临时存储的电容器电压进行平衡。