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涡街流量计有许多优点, 近年来应用广泛。但它易于受到由管道振动和流场扰动引起的噪声干扰。用传统的处理信号电路制成的流量计在工业现场测量精度不高, 抗干扰性能差, 无法准确测量小流量。而数字信号处理技术可以弥补传统方法的不足。归纳了数字滤波器、谱分析、自适应陷波以及小波变换等几种方法, 介绍了每一种方法的具体实现, 并作了性能分析和比较。指出数字信号处理方法可以很大程度上提高测量精度, 实现真正小流量测量。但实际应用中需要考虑到准确性和实时性要求。通过MATLAB仿真实验, 验证了采用变采样频率和频谱校正等措施对经典周期图法进行改进, 既可以达到较高的精度, 扩展了量程下限, 又能够满足以单片机为核心的流量计低功耗和实时性要求, 实用性较强。
Vortex flowmeter has many advantages, widely used in recent years. However, it is susceptible to noise interference caused by pipe vibrations and flow field perturbations. Flow meter with the traditional processing of signal circuit measurement in the industrial field is not high accuracy, anti-jamming performance is poor, can not accurately measure the small flow. The digital signal processing technology can make up for the lack of traditional methods. Summarized several methods of digital filter, spectrum analysis, adaptive notch and wavelet transform, introduced the concrete realization of each method, and made the performance analysis and comparison. It is pointed out that the digital signal processing method can greatly improve the measurement accuracy and realize the real small flow measurement. However, the actual application needs to take into account the accuracy and real-time requirements. Through MATLAB simulation experiments, it is verified that the classical periodic graph method can be improved by using variable sampling frequency and spectrum correction, which can achieve higher accuracy, extend the lower range limit, and meet the low power consumption And real-time requirements, practicality.