| 摘要 |
Microwaves are respectively propagated through a reference fluid and fluid to be measured, both contained in a detection pipe body, and as a result, a first phase lag theta1 and a second phase lag theta2 can be determined on the basis of the microwaves by a phase lag measuring circuit. Then, a density computing circuit subtracts the first phase lag theta1 from the second phase lag theta2 to determine a phase difference DELTAtheta. When computing the density of matter in the fluid on the basis of the phase difference DELTAtheta, the density computing circuit performs density computing processing such that a real second phase lag theta2 satisfies the following equationwhere N is the number of rotations, and theta2' is an apparent phase lag obtained by the phase lag measuring circuit. Then, if the density does not fall within a checking range defined by upper and lower limit values, a rotation-number checking circuit increases or decreases the number N of rotations such that the density falls within the checking range.
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