涡街流量传感器信号处理方法研究

Research on Signal Processing Method of Vortex Flow Meter

设计一种基于变增益运算放大器和DSP数字信号处理单元的新型涡街流量计信号处理电路。利用DSP上集成的模拟数字转换电路(A/D)实时检测涡街流量计传感器输出信号的幅度和频率,采用数字模拟转换电路(D/A)对变增益运放进行控制,控制传感器输出信号幅度的相对稳定。针对涡街流量计输出信号的频率特性,设计基于DSP的FIR滤波算法,实现输出信号噪声的初步抑制,削弱原始信号中强噪声干扰。滤波后信号由DSP进行频率信息的精确计算以及流量的解算。实验结果表明,变增益运算放大电路有效解决了涡街流量计传感器输出信号幅度变化范围大而造成的放大电路复杂,分段放大信号幅度不连续等问题;采用DSP进行数字滤波及频率计算,实现了信号中噪声的抑制以及高精度流量解算。

A new signal processing circuit of vortex flow meter based on variable gain amplifier and digital signal processor（DSP） unit is designed. It measures the range and frequency of the vortex flow meter output signals by the analog to digital converter（A/D） of the DSP on real time, and the gain of the variable gain amplifier is controlled by the digital to analog converter（D/A）, then the relative stable range of the sensor output signals can be obtained. Due to the frequency characteristic of the vortex flow meter output signals, a FIR filter arithmetic based on the DSP is designed, it effectively inhibits strong noise in the out- put signals. And then the frequency of the filtered signal and the flux of the liquid are calculated by the DSP. The experimental results show that the complex amplifier circuit due to the large variable range of the vortex flow meter output signals and the discontinuous problem of the signals are solved by the variable gain amplifier. The noise of the signals is effectively restrained and the flow rate is calculated precisely because the DSP is adjusted for digital filtering and frequency calculation.