| 摘要 |
PROBLEM TO BE SOLVED: To provide a coriolis flowmeter and a frequency measuring method having small errors and variations of measurement frequency even when noise is superimposed on a detection signal or a signal obtained by digitally processing the same. SOLUTION: In the coriolis flowmeter 100 in which a measuring tube through which a measurement fluid flows is vibrated and which includes an in-phase digital filter means 21A detecting a vibration including coriolis force generated in the measurement fluid by the vibration and for output of a digital signal having a phase the same as the detection signal and an out-of-phase digital filter means 21B for output of a digital signal having a phase different from the detection signal by 90 degrees, the coriolis flowmeter includes a frequency calculation means 110 for calculating a frequency of the detection signal on the basis of the in-phase digital signal DA4 and the digital signal DA5 having the phase that is different by 90 degrees when a value based on the in-phase digital signal DA4 and the digital signal DA5 having the phase that is different by 90 degrees is outside a prescribed range. COPYRIGHT: (C)2011,JPO&INPIT |
