数字式超声波气体流量计的信号处理及改进

利用超声波测量气体流量具有非接触、安全、精确度高等优点。介绍了基于DSP的超声波气体流量计的工作原理及硬件设计框架;针对其接收信号弱、工作环境噪声强的特点采用相关法分析,并分别从时域和频域阐述了相关法的原理和算法;在保证精度的前提下提出了算法改进措施以提高其实时性,并给出了板上调试的具体实例;首次提出利用回波法求基准波的方法;针对不同系统的要求提出了三种提高精度的措施。以上方法成功应用于仪表设计中。

Signal Processing and Improvement Measures for Ultrasonic Gas Flowmeter Based on DSP

It has the quality of safety,non-touching and high precision to measure gas flux with ultrasonic.The principle of ultrasonic gas flowmeter based on DSP and the frame of its hardware design are introduced here.It adopted correlation method because of weak signal reception and strong noise surroundings and came true respectively in time and frequency domain.Ensuring the accuracy,it took some improvement measures for better quality of real-time.For the first time it made use of echo method to get the reference wave.Three measures can be taken to enhance the precision for different system requests.All the methods above have been proved useful in the design of ultrasonic gas flowmeter.