Adaptive filter with sweep filter analyzer for a vortex flowmeter

A digital signal processing system operating in conjunction with a vortex flowmeter passes a digital representation of a flowmeter signal into a multistage decimator having two outputs. The two outputs correspond to the vortex flowmeter signal downsampled to two different sampling frequencies. One of the two outputs passes to an on-line channel having an adaptive bandpass filter for tracking the fundamental frequency of the vortex flowmeter signal, thereby continuously monitoring the flow rate. The other of the two outputs passes to an off-line channel having a tunable bandpass filter that can be used to observe frequency components other than those near the fundamental frequency. The system thus enables maintenance personnel to conveniently monitor the noise spectrum generated by the flow without interrupting the operation the flow measurement.