| 摘要 |
PURPOSE:To decrease error due to sudden change in electrochemical DC noises in detecting the sudden change in the electrochemical DC noises by outputting the value obtained from the sample value before the detection of the sudden change. CONSTITUTION:An exciting current, which has 1 cycle comprising 4 periods of positive, zero, negative, and zero, is flowed in an exciting coil 1. The output of the differential amplifier 6 is sampled at every period by an A/D converter 8. The digital sampled value is stored in a memory 10. Then a CPU sequentially compares each stored sample value with the sample value 1 step earlier. When the difference is larger than the predetermined value, it is judged that the sudden change in the electrochemical DC noises has occured. Instead of the sample value of the sudden change detection, the amount of variation is added to the sample value before the sudden change detection and outputted. Thus the error due to the sudden change in the electrochemical DC noises can be decreased. |
