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频率、幅度和相位均按随机游动模型变化的时变信号模型,能更为真实地描述科氏流量计信号的实际特性。基于时变模型,提出了一种新的科氏流量计信号处理方法。首先对通过带通FIR滤波器的科氏流量计信号进行短时频率估计;然后通过短窗截取,采用计及负频率影响的DTFT法计算两路信号的相位差和时间差。仿真分析表明,提出方法具有很好的跟踪效果,且计算量小,可用于科氏流量计的实时信号处理。
The time-varying signal model, whose frequency, amplitude and phase change according to the random walk model, can describe the actual characteristics of the Coriolis flowmeter signals more truthfully. Based on the time-varying model, a new signal processing method of Coriolis flowmeter is proposed. Firstly, short-term frequency estimation of Coriolis flowmeter signal with band-pass FIR filter is carried out. Then the phase difference and time difference of two signals are calculated by short-cut interception and DTFT method which takes the influence of negative frequency into account. Simulation results show that the proposed method has a good tracking effect, and the calculation is small, which can be used for real-time signal processing of Coriolis flowmeter.