A 4⁃link ultra⁃wideband receiving subsystem is described,which mainly deals with the 2~18 GHz RF signals re⁃ceived by the antenna. The processes of amplitude limiting,amplifying,mixing,filtering,detecting and measuring are per⁃formed for the signal respectively to form the intermediate frequency signal,and then the signal is sent to the signal processing subsystem. In this paper,the design scheme of the system is introduced,the system working principle is described in detail, and the important parameters of the selected component are listed for discussion. The circuit gain,noise figure,linearity and other significant parameters of the system are computed and analyzed with the electromagnetic simulation software ADS. The de⁃sign results show that the system noise figure is 3.5 dB,sensitivity is -73.5 dBm,dynamic range is 50 dB,output signal fre⁃quency is 1.5 GHz,and the power can be stabilized at about 0 dBm.%描述一种超宽带四链路接收分系统，该系统主要处理天线接收到的2~18 GHz的射频信号，分别通过对信号进行限幅、放大、混频、滤波、检测、测量等过程形成中频信号，并送至信号处理分系统。首先介绍该系统的设计方案，并对系统的工作原理进行详细说明，随后列出所选器件的重要参数以便讨论，通过使用电磁仿真软件ADS计算分析系统内电路的增益、噪声系数和线性度等重要参数。其中系统噪声系数为3.5 dB，灵敏度为-73.5 dBm，动态范围为50 dB，输出信号为1.5 GHz，且功率稳定在0 dBm左右。
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