SIGNAL PROCESSING METHOD, SIGNAL PROCESSING APPARATUS, AND CORIOLIS FLOWMETER

摘要

A signal processing apparatus for a Coriolis flowmeter has a transmitter for outputting a modulatable frequency signal, a frequency conversion section and a phase difference measurement section. The frequency conversion section performs frequency conversion and frequency shifting of input signals detected by vibration detection sensors of the Coriolis flowmeter by adding or subtracting a frequency of the modulatable frequency signal output from the transmitter to or from frequencies of the input signals so as to output frequency converted signals. The signal processing apparatus controls the frequency of the modulatable frequency signal output by the transmitter so that frequency values of the frequency converted signals obtained by the frequency conversion are always constant. The phase difference measurement section measures a phase difference between the frequency converted signals output from the frequency conversion section.