一、概述 DB791型数字电平表是自动测试电报信号的数字式仪表,可显示三位数字.被测信号频率范围为300赫～10千赫;信号电平测量范围为+11分贝至-70分贝;测试速度为1.2秒;测量精度为±0.4分贝.本仪表专为自动化测试而设计,有数据输出,供电传打字机打印电平数值,能配合电报自动化测试. 图1是该电平表的原理方框图.模拟信号通道的作用是将被测信号变换成某一电平范围内的直流信 I. Overview The DB791 digital level meter is a digital meter that automatically tests the telegraph signal and can display three digits. The measured signal frequency range is 300 Hz ~ 10 kHz; the signal level measurement range is +11 dB to -70 Decibel; test speed of 1.2 seconds; measurement accuracy of ± 0.4 dB. The instrument is designed for automated testing and design, data output, power supply typewriter print level values, with telegraph automation test. Figure 1 is the level meter Principle block diagram.Analog signal channel role is to be measured signal into a range of levels of DC