| 摘要 |
PURPOSE:To improve measurement accuracy by providing a mixing circuit which mixes both detection signals of 1st and 2nd vibration detectors at a ratio corresponding to their output levels between the 1st and 2nd vibration detectors and an A/D converter. CONSTITUTION:A body 2 to be tested is rotated to detect vibrations caused by its unbalance by the 1st and 2nd vibration detectors 10a and 10b. The 1st and 2nd vibration detectors 10a and 10b output detection signals corresponding to the quantity of the unbalance, so those detection signals are both inputted to a mixing circuit 12. The mixing circuit 12 mixes both detection signals at the ratio corresponding to their output levels to make common component that the detection signals contain cancel each other. Consequently, only a component which contains the unnecessary unbalance quantity is led out of the mixing circuit 12. The signal from the mixing circuit 12 is digitized by an A/D converter 28, so the input signal at the time of A/D conversion is handled as a 100% effective signal. Consequently, the measurement accuracy of two-surface separate arithmetic processing can be improved.
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