| 摘要 |
In order that a flow tube of a Coriolis flowmeter may be vibrated in a tertiary mode using one drive device, the drive device is arranged at an antinode in the center of tertiary mode vibration, and vibration detecting sensors are arranged at two antinodes other than the antinode in the center of tertiary mode vibration. Moreover, the displacement polarity of the drive device is opposite to that of the vibration detecting sensors so that the vibration phases of the flow tube are in a relation of mutually opposite phases. Furthermore, in a positive feedback loop of an excitation circuit portion for exciting tertiary mode vibration of the flow tube and the vibration detecting sensors , the excitation circuit portion is structured so that the relation between the displacement polarities where the vibration phases of the flow tube are opposite to one another is converted to the relation where the vibration phases of the flow tube are in phase.
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