| 摘要 |
An ultrasonic flowmeter, wherein upstream and downstream receive signals are A/D-converted and thereby the discrete values thereof are determined: a cross-correlation between the upstream and downstream receive signals is determined: the result of calculation by correlation processing means is Hilbert-transformed; a phase relationship is determined by phase calculating means from the results of calculation by the correlation processing means and calculation by Hilbert transform; and a time difference in calculated from the phase calculation result provided by the phase calculating means through maximum value decision means.
|
