摘要
针对气体超声波流量计信号处理中很难确定特征点的问题,提出一种基于可变阈值过零检测的信号处理方法,准确地找到信号的特征波,从而求得超声波信号的传播时间,准确测量气体流量。在以DSP和FPGA为双核心的气体超声波流量计信号处理系统上实时实现这种方法。采用判断"台阶"的方法,剔除噪声干扰所带来的误差,提高测量结果的稳定性。采用分段线性校正的方法,修正非线性误差,提高系统的测量精度。气体流量标定实验结果验证了方法和系统的有效性。
Aiming at the difficulty in determining the feature point in the signal processing of gas ultrasonic flowmeter, a variable threshold based zero-crossing detection signal processing method is proposed to determine a feature wave of the signal accurately. Thus the propagation time of ultrasonic signal is calculated, and the gas flow rate is measured accurately. This method is realized real time in a signal processing system with DSP and FPGA as dualcore for the gas ultrasonic flowmeter. By judging the ＂step＂, the error caused by noise interference is eliminated, and the stability of the measurement results is enhanced. With piecewise linear calibration, the non-linear error is corrected, and the measurement accuracy of the system is improved. The experimental results of gas flow calibration verify the effectiveness of the method and the system.
出处
《电子测量与仪器学报》
CSCD
北大核心
2015年第9期1365-1373,共9页
Journal of Electronic Measurement and Instrumentation
关键词
超声波
传播时间
可变阈值
过零检测
数字信号处理
ultrasonic
propagation time
variable threshold
zero-crossing detection
digital signal processing
