无线电高度表信号模拟器射频信号延时/衰减模块设计

Design of RF Signal Time Delay and Attenuation Module of Radio Altimeter's Signal Simulator

无线电高度表程控信号模拟器是无线电高度表自动测试系统（ATE,ATS）的重要组成部分,而射频信号延时/衰减模块则是无线电高度表程控信号模拟器3个功能模块组件中的核心模块。研制了一种采用声表面波（SAW）延迟线作为射频信号延时器件、射频衰减器作为射频信号功率衰减器件,通过程控射频开关控制不同声表面波延迟线的切换,包含射频信号变频、放大等结构电路的无线电高度表信号模拟器射频信号延时/衰减模块。经无线电高度表自动测试系统的实际工程应用表明,该无线电高度表射频信号延时/衰减模块对C波段（4.2～4.4 GHz）射频调制信号的延时精度高、衰减范围大,体小、质轻,适合置于无线电高度表测试适配器内部使用,具有较高的工程应用价值。

The radio altimeter＇ s signal simulator is one of the most important parts of radio altimeter＇ s automatic test equipment （ATE, ATS）. The module used for RF signals＇ time delay and attenuation, one of three function modules, has the essential function of this simulator. We have designed and manufactured this module. It used the surface acoustic wave （SAW） delay lines to delay RF signals, and used attenuator controlled by program to weak RF signals. We devised some RF switchs to choose one of SAW delay lines to use. We also devised RF mixer and RF amplifier as assistant circuit. Successful utilization in radio altimeter＇s ATE has proved that this delay and attenuation module has very high practical value, because it has high precision and it is small and light.