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一、引言现代的扫频讯号发生器,大多是采用返波管、电压调谐磁控管和微波晶体管,而且都具备良好的自动的功率电平控制设施,因而可以改善系统的测试精度(见第一篇译文)。由于有了稳幅的功率输出,所以指示系统可以不用比值计而在一定的指示灵敏度范围内,实现快速扫频测试。我们知道:指示系统的灵敏度与扫频速度之间存在着内在的矛盾,要提高扫频速度,就要牺牲指示器的灵敏度为代价。目前,可供电平控制使用的电调衰减器有铁氧体和晶体管两种。由于晶体管的惯性小,要求电控的功率小和重量轻等优点,所以通常采用的都是PIN二极管构成的电调衰减器。
I. INTRODUCTION Modern scan signal generators mostly use back-wave tubes, voltage-tuned magnetrons and microwave transistors and have good automatic power level control facilities to improve the system’s test accuracy A translation). Due to the stable power output, the indicator system can achieve fast sweep test without the ratio meter within a certain indication sensitivity. We know: there is an inherent contradiction between the sensitivity of the indicator system and the sweep speed, and the speed of sweep is sacrificed at the expense of the sensitivity of the indicator. At the moment, there are two kinds of ferrite and transistor for the electric attenuator used for level control. Due to the small inertia of the transistor, the need for electronic control of small power and light weight, etc., so are usually used PIN diodes constitute the electronic attenuator.