| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a coriolis mass flowmeter in which the number of FIR filters can be reduced with respect to a wide sensor signal frequency range. <P>SOLUTION: In a coriolis mass flowmeter, a tube in which a fluid flows is oscillated, signals obtained from an upstream oscillation sensor and a downstream oscillation sensor are sampled at desired intervals, filtering processing is performed and a phase difference and frequencies of the upstream oscillation sensor signal and the downstream oscillation sensor signal are calculated to measure a mass flow and a density of the fluid. The coriolis mass flowmeter includes upstream side decimation means and downstream side decimation means provided between upstream side and downstream side low-pass filters and FIR filters for executing input signal thinning processing, and decimation ratio selection means which sets a thinning rate to the upstream side decimation means and the downstream side decimation means in such a manner that a passband of the upstream side and downstream side FIR filters is compatible to the frequencies of the upstream oscillation sensor signal and the downstream oscillation sensor signal. <P>COPYRIGHT: (C)2012,JPO&INPIT |
