基于能量变化率的气体超声波流量计信号处理方法  

Rate of energy based signal processing method for ultrasonic gas flowmeter

作　　者：沈子文[1] 徐科军[1,2] 方敏[1] 朱文姣 汪伟[1] 

机构地区：[1]合肥工业大学电气与自动化工程学院,合肥230009 [2]工业自动化安徽省工程技术研究中心,合肥230009

出　　处：《仪器仪表学报》2015年第9期2138-2144,共7页Chinese Journal of Scientific Instrument

摘　　要：针对气体超声流量计信号处理中不易找到稳定的测量特征点的问题,提出了一种基于能量变化率的过零检测信号处理方法,以及最优阈值参数的选取方法。基于能量变化率的过零检测信号处理方法首先求取能量变化率曲线上的关键阈值点,然后回溯到原始波形信号上,找到对应的过零点,并以此作为信号的稳定特征点,进而求得信号的传播时间及气体流量。在以FPGA和DSP为核心的气体超声流量计信号处理系统上实时实现了算法,并进行标定实验,实验结果验证了方法的有效性。Aiming at the problem that it is difficult to find stable feature point in the signal processing of ultrasonic gas flowmeter, a zero-crossing detection signal processing method based on the rate of energy and a method for determining the optimum threshold parameter are proposed. Firstly, this zero-crossing detection signal processing method obtains the key threshold point on the rate of energy curve, then traces back to the original waveform signal and obtains the correlated zero-crossing point, which is taken as the stable feature point of the signal. Finally, the propagation time of the ultrasonic signal is calculated and the gas flow rate is measured accurately. This method was implemented in real time in the signal processing system of the ultrasonic gas flowmeter with DSP and FPGA as the dual-cores, and calibration experiment was conducted. Gas flow calibration experiment resuhs verify the effectiveness of the proposed method.

关 键 词：超声波 传播时间 能量变化率 过零检测 数字信号处理 

分 类 号：TH814.92[机械工程—仪器科学与技术]