谐振式液体密度传感器的频率解算方法研究

为实现高精度测量谐振式液体密度传感器的输出信号频率,在现有的FFT频率解算理论基础上,引入更符合实际情况的加窗插值FFT频率解算方法,并分析频率变化以及噪声对解算结果的影响。通过Matlab仿真实验对该方法中常用的窗函数进行对比分析,最终选择加入Rife_Vincent窗的插值FFT算法作为输出信号频率的解算方法,并在所设计的硬件系统上进行了实验验证,结果表明,采用加Rife_Vincent窗的插值FFT算法解算传感器输出信号的频率,其解算误差小于0.1Hz,解算精度高且易于实现。

Research on the Frequency Calculation of the Resonant Sensor for Liquid Density Measurement

In order to increase the accuracy of frequency calculation for the density sensor based on the resonance theory, interpolated Fast Fourier Transform algorithm （ FFT） algorithm which is based on the existing FFT and more adjusts the actual situation is introduced. The effect of frequency changes and the noise on results of frequency calculation is also analyzed. Comparative analysis for the commonly used windows is made through Matlab, and Rife_Vincent window is chosen finally. In addition, experiments have been carried out on the hardware system designed. The experimental results confirm that the calcu-lation error is less than 0. 1 Hz by means of the interpolated FFT algorithm with Rife_Vincent window. The results also test and verify that the method has very high accuracy and is easy to realize.