Noise reduction filter system for a coriolis flowmeter

Abstract

A noise reduction system and method for measuring the phase difference between output signals of a Coriolis flowmeter. The output signals are applied to signal processing circuitry having three measurement channels, each of which includes a multi-pole filter having a relatively large phase shift. A channel pair is alternately switched in successive time intervals between a calibration status and an active status. In the calibration status, the two channels are connected during one time intervals to the same input signal and the output signals of the two channels are measured to determine the inherent phase delay between the two calibration channels. The two channels are then switched during the next time interval to an active status in which they are connected separately to the two output signals from the flowmeter. The output signals of the channels are then measured and the resultant measured phase delay is algebraicly combined with the phase delay measured during the calibration status to determine the true phase delay between the two signals received from the Coriolis flowmeter.