| 摘要 |
PURPOSE:To perform accurate measurement of the amount of variation at all times by automatically updating the zero adjusting value at a specified interval, and adjusting the zero point of a detected signal by said zero point adjusting value. CONSTITUTION:Electric charges collected 12 in an ionization chamber 10 are converted to a voltage signal. ON and OFF operations of a switch 30 in a meter 14 is controlled by a switching signal from a zero point adjusting circuit 18. The output of an AD converter 16 is supplied to a register 36 when the switch 30 is turned OFF and supplied to a register 32 when the switch 30 is turned ON. The outputs of the registers 32 and 36 are operated 40, and the zero point is adjusted. When an FF 44 is inverted for a specified time by the output of a time 42 in a circuit 18, a contact 38 is turned OFF, and the supply of signal to the register 36 is stopped. When a signal is outputted Q from the FF 44, the switch 30 and the contact 34 are turned ON, and the detected signal under the zero checking state is supplied to the register 32, and the zero point adjusting value is updated. |
