通用示波器计量规程规范述评

Analysis and Review of Metrological Specifications for General-Purpose Oscilloscopes

综述了现行有效的通用示波器检定规程和校准规范,涵盖模拟示波器和数字示波器,对各自的计量校准和检定项目设置、技术思想以及计量技术特点进行了全面而系统的分析。模拟示波器的计量检定,一直是以屏幕波形的特征值直接读取法来获得其性能指标特性,覆盖输入探头、通道放大器、扫描电路、高压电子枪、阴极射线管显示等各个部分共同作用的结果,其波形稍纵即逝,很难使用屏幕直接读取法以外的方式获得全面有效的计量结果;数字示波器基于A/D采样技术制造,影响其测量性能的部分主要包括输入通道放大器、采样电路、A/D转换器等,与显示部分的性能没有特别关系,测量结果可以永久保存的为采样波形序列,因而既可以通过直接屏幕读取法计量校准,也可以使用电子计算机,以数字信号处理方式获得性能结果。分别从技术指标的全面性与准确度、校准方法与技术手段的难易程度、自动校准手段的适宜与否、所用标准仪器的多寡等几个方面,讨论了两类示波器检定规程及校准规范各自的优点与不足,为上述各个规程规范的使用、修订、完善及后续计量技术研究提供了参考和借鉴。

This article provides a comprehensive review of the current effective verification regulations and calibration specifications for general-purpose oscilloscopes,encompassing both analog and digital types.It systematically analyzes the metrological calibration and verification items,technical concepts,and measurement characteristics of each oscilloscope category.For analog oscilloscopes,calibration has traditionally relied on the direct reading method from screen waveforms,reflecting the combined effects of input probes,channel amplifiers,scanning circuits,high-voltage electron guns,and cathode ray tube displays.The transient nature of these waveforms makes it challenging to obtain comprehensive and effective measurements through methods other than direct screen reading.Conversely,digital oscilloscopes,built on A/D sampling technology,focus mainly on input channel amplifiers,sampling circuits,and A/D converters,with their display performance being less relevant.The measurement results,represented as saved sampling waveform sequences,allow for calibration through both direct screen reading and digital signal processing via computers.The article discusses the strengths and weaknesses of verification regulations and calibration specifications for both oscilloscope types,considering the comprehensiveness and accuracy of technical indicators,the difficulty of calibration methods and techniques,the appropriateness of automatic calibration methods,and the range of standard instruments required.The analysis provides a reference for the application,revision,improvement,and future metrological research of these regulations and specifications.