一、引言仪器仪表是在生产和科学实验中用来观察、计量和控制的重要工具。它的发展水平也是衡量一个国家现代化水平的重要标志之一。带有指针和标尺的模拟式仪表历史悠久,至今仍占有显示仪表的一定地位。不过,随着脉冲数字电路的发展,各种数字仪表相继出现,特别是近些年来,随着电子技术的发展及大规模集成电路的广泛应用,已出现的数字式仪表又在向廉价、高性能方向发展,这就使得数字 I. INTRODUCTION Instrumentation is an important tool for observation, measurement and control in production and scientific experiments. Its level of development is also one of the important indicators of the modernization of a country. Analog meters with hands and rulers have a long history and still occupy some of the display instruments. However, with the development of pulse digital circuits, various digital instruments have appeared one after another. Especially in recent years, with the development of electronic technology and the widespread application of large-scale integrated circuits, digital instruments that have emerged are being offered to cheaper, Performance direction, which makes the figures