| 摘要 |
A Coriolis-type fluid flow rate measuring system useing phase locked loop-based signal processing to estimate a tube vibration signal and maintain optimum tube vibrations. Analog sinusoidal sensor signals (x1(n), x2(n)) from the flow meter are digitized and processed through heterodyne mixing (96, 98) as part of phase locked loop tracking of the fundamental vibration or oscillation frequency. Digital signal processing is used to implement filtering (100, 102) and signal manipulation (110, 112, 126, 128) for determining phase and frequency estimates (94, 92) for both digitized signals. Frequency estimate data is used to adjust the tracker frequency mixed with the sensor signals. Phase and frequency estimate data are used to determine an optimized drive signal for tube vibration. Phase estimate information for the sensor signals is used to determine phase shift data and in turn used to determine fluid flow rate.
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