Abstract: Coriolis flowmeter measures mass flow by computing the time difference of two sinusoidal signals outputted with the same frequency by its primary instrument. It is crucial to estimate the frequency and phase difference of the two signals accurately and real-time in the digital signal processing of Coriolis flowmeter. Using the actual Coriolis flowmeter signals collected, it presents a method to calculate time difference which based on interpolation FFT for frequency estimation and through improved sliding DTFT considering negative frequency for phase difference estimation. This method balances high precision with computational efficiency. Contrast experiment verifies the availability and advantage of this method.

Key words: Coriolis mass flowmeter, digital signal processing, interpolation Fast Fourier Transform（FFT）, sliding Discrete Time Fourier Transform（DTFT）, phase difference

摘要： 科氏流量计通过计算一次仪表输出的两路同频正弦信号的时间差来测量质量流量。实时精确估计两路信号的频率和相位差是科氏流量计数字信号处理的关键。针对科氏流量计实测信号，提出一种基于插值FFT和滑动DTFT的信号处理方法。利用插值FFT估计信号频率，通过计及负频率的改进滑动DTFT估计相位差，进而计算出时间差。方法兼顾了参数的估计精度和算法的计算效率，对比实验表明了该方法的有效性和优越性。

关键词: 科氏流量计, 数字信号处理, 插值快速傅里叶变换（FFT）, 滑动离散时间傅里叶变换（DTFT）, 相位差