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本文介绍一种用微处理机-高速采样系统准确测量波速的方法。波速测量的精度取决于走时的确定。但目前大都采用SYC-Ⅱ型波速仪,并靠眼睛判读其示波器上光标的位置来得到走时,由此产生的走时读数误差往往超过0.2微秒。应用本文介绍的系统,这一误差可以大大减少。在测量过程中,走时被一瞬态记录仪用20兆赫兹的最高采样速率(对应的最大读数误差为0.05微秒)记录下来,然后经过一数字接口将数据输入微处理机,由其自动判读波的初动,并立即给出波的走时和速度。 分析表明,对实验室通常采用的样品尺度,该系统的波速测量误差在0.7％以内,波速测量的精度因而得到很大程度的提高。
This article describes a microprocessor - high-speed sampling system to accurately measure the wave speed method. The accuracy of wave velocity measurement depends on the determination of travel time. However, most of the current use of SYC-Ⅱ-type anemometer, and rely on the eyes of the oscilloscope to determine the location of the cursor to get go, the resulting travel time reading error is often more than 0.2 microseconds. Using the system described in this article, this error can be greatly reduced. During the measurement, the travel time was recorded by a transient recorder at a maximum sampling rate of 20 MHz (corresponding to a maximum of 0.05 microseconds of error) and then entered into the microprocessor via a digital interface, automatically interpreted The wave of the first move, and immediately give the wave of travel time and speed. The analysis shows that the accuracy of wave velocity measurement is greatly improved when the error of wave velocity measurement is within 0.7% for the sample scale commonly used in the laboratory.