| 摘要 |
PURPOSE:To attain AD conversion and to exclude noise, by sampling an analog signal in the same period as noise signals in the analog signal, converting the picked-up signal into a digital signal and averaging the digital signal in the period CONSTITUTION:When the period of a noise of a noise signal Vr is, e.g. 16.7ms, an input analog signal superimposed with the Vr is sampled for 16 times per 1ms for example, and the sampled values V1-V16 are stored in the assigned address of an RAM. An average value V1 of 16 sampled values in the period 16.7ms of noise signals is obtained by using equation by using a microcomputer 2. Thus, the component in one period of the noise signals is almost cancelled, and a normal digital signal not subjected to the interference of the noise signals can be obtained. As to general AC noise signals, the sampling period has only to be taken to split the period of the noise signals in almost 2<n>-split (where; n is a positive integer). |
