超声波流量计的高精度测量技术

本文研究了时差法超声波流量计传播时间的测量技术，采用高性能的复杂可编程逻辑器件（CPLD）代替分立器件，以提高系统的稳定性和可靠性；利用超声波信号的自动增益控制（AGC）和复杂的逻辑控制实现信号的精确测量；利用逻辑分析实现倍频，使计数器的计数频率达到160MHz，通过软件和硬件方法实现传播时间范围控制和可靠性检验。实验结果表明，超声波传播时间误差在7纳秒以内，达到了设计要求。

Accurate Measurement Technology of the Ultrasonic Flowmeter

It is presented the measurement technology of the ultrasonic travel time of the ultrasonic flowmeter in this paper. It applied the high|performance complex programmable logical device instead of single devices in order to develop the stability and reliability of the system. It made use of the signal automatic gain control (AGC) and complex logical control to realize the precise measurement of the ultrasonic signal, and made use of the logical analytical method to realize double frequency and 160 MHz frequency of the counter. It achieved travel time range control and reliability analysis through software and hardware ways. The result confirmed that the acoustic travel time error was no more than 7 ns and achieved the design objective.