中文摘要：

为了使弱信号区或盲区的不同移动台能顺利进行通信，提出了适用于WCDMA直放站上行链路的负反馈双环自动增益控制（AGC）电路，并采用两级射频AGC电路分别控制上行链路输入端和输出端的增益，达到自动控制输出功率的目的。利用电路设计软件ADS分析构建系统的性能，仿真结果显示：有AGC的直放站上行链路系统频率和信道选择性好、输出功率稳定可调、AGC增益范围大和输出功率范围宽。该系统能够较好解决移动台盲区通信的问题。

英文摘要：

In order to communicate successfully for various mobile stations in signal weak and dead zone, a dual-loop automatic gain control （AGC） circuit associated with an inverse-gain feedback is presented, which is used in WCDMA repeater uplink system. The repeater uplink employs two-stage radio frequency AGC circuit, which adjusts input and output part gain of the repeater respectively, so that the system can operate normally and control automatically the output power. Agilent advanced design system （ADS） is used as a simulation tool to analyze the performance. The results indicate that it performs well, and it has the characteristic of good frequency selectivity and channel selectivity, steady controllable output, large range of AGC gain and wide range of output power. Thus, the proposed system is suitable for solving the problem of the dead zone in WCDMA communication.