针对泄漏电缆入侵检测系统接收信号微弱、易受环境影响等问题,提出一种新型高灵敏度、大增益的直放式接收机射频前端电路,优化放大增益和噪声系数,提高系统稳定性,其结构以宽带带通滤波器、超低噪声放大器CMA5043、固定增益模块Hmc580、自动增益控制模块(AGC)AD8331为核心。实验结果表明,在26.25-36.25MHz通带内,滤波器的插入损耗小于1.4dB,电路噪声系数小于1.1dB、可识别的最小信号Smin为-118dBm,实现80-100dB增益可调,系统工作稳定。 Aiming at the problems such as weak reception signal and susceptible to environment in leakage intrusion detection system, a new type of high sensitivity and large gain radio receiver front end (RF) front-end receiver is proposed to optimize amplification gain and noise figure and improve system stability. The structure Broadband band-pass filter, ultralow noise amplifier CMA5043, fixed gain module Hmc580, automatic gain control module (AGC) AD8331 as the core. The experimental results show that the insertion loss of the filter is less than 1.4dB and the noise figure of the circuit is less than 1.1dB in the passband of 26.25-36.25MHz. The smallest signal Smin that can be identified is -118dBm. The gain of 80-100dB is adjustable and the system is stable .