【摘要】 为克服气体涡轮流量计存在压损和需定期校准的缺点，研制了耐高压低功耗单声道气体超声波流量计。针对换能器因阻抗不匹配造成的回波信号质量差的问题，分析了回波信号的特征，提出了动态可变阈值和过零检测的数字信号处理方法。该方法可精准定位回波信号特征点。研制了以STM32为核心的低功耗气体超声波流量变送器。变送器采用了新的激励方式，既能防止MOSFET电路的两路输出同时导通，又节省激励功耗；采用脉冲累计发送和最优脉冲分频相结合的方式，减小脉冲上传误差。气体流量标定实验结果表明：研制的低功耗单声道气体超声波流量计满足1级精度指标的要求，量程比为1：21。更多还原

【Abstract】 To overcome the shortcomings of pressure loss and the need for regular calibration with gas turbine flowmeter, a mono-channel gas ultrasonic flowmeter with high-pressure resistance and low power consumption is developed.In order to solve the poor quality of the echo signal caused by the impedance mismatch of the transducer, the features of the echo signal are analyzed.A digital signal processing method based on dynamic variable threshold and zero-crossing detection is proposed to accurately locate the feature point of the echo signal.A low-power gas ultrasonic flow transmitter with STM32 as the core has been developed, and a new excitation method is designed, which can not only prevent the two-way outputs of the MOSFET circuit from being turned on at the same time, but also save the excitation power consumption.The combination of pulse cumulative upload and optimal pulse frequency division reduces the pulse upload error.The gas flow calibration experiment results show that: the developed low-power mono gas ultrasonic flowmeter meets the requirements of the indicators of level 1 accuracy, and the range ratio is 1：21.更多还原