超宽带系统中的快速双闭环自动增益控制算法

摘要

Aiming at the demands of signal with large dynamic range in Ultra Wide Band(UWB) receiver, this paper presents a double closed-loop Automatic Gain Control(AGC) algorithm. Compared with the conventional AGC algorithm, a novel double closed-loop structure is adopted to get a large adjustment range and high convergence. The first AGC loop before synchronization block is used for coarse tuning, the second AGC loop after synchronization block calculates the power of preamble to approximate the reference power, it is used for fine tuning. Simulation of the algorithm is based on the DC-OFDM UWB receiver and Gaussian channel. Simulation results show that the proposed AGC algorithm can effectively expand the adjustable range of gain to 80 dB, further more it can improve convergence speed.%针对宽带接收机中大动态信号的通信要求，提出一种快速双闭环自动增益控制(AGC)算法。该算法采用双闭环增益控制结构，在扩大增益调节范围的同时提高收敛速度。第1个自动增益控制闭环位于同步器之前，用以调整接收信号幅度使其被同步器检测到，实现粗调的目的；第2个AGC闭环位于同步器之后，根据前导符进行能量估计，通过反馈使其逼近参考增益，实现细调的目的。基于双载波的正交频分复用系统的仿真结果表明，该算法可将增益的调节范围扩大到80 dB，同时提高AGC的收敛速度。