基于FPGA的大动态数控AGC系统设计

自动增益控制(AGC)是接收机的重要问题,传统模拟实现精度不高、灵活性差、调试复杂。介绍了一种大动态数控AGC实现方法,直接累加均方值估算信号功率,经对数运算后与参考值比较,得到对应需放大或缩小的功率值,通过查表再反馈控制前端,全过程由程序控制实现,执行元件为DVGA芯片AD8370。仿真及实测结果表明,该方法对信号功率变化响应迅速、控制精度较高,且适合FPGA实现,动态范围可达70dB。

Design of Large Dynamic Range Digitally Controlled AGC Based on FPGA

AGC is a cruxe of receiver.The flexibility of analogical method is very low and it is hard to debug.A kind of large dynamic range digitally controlled AGC has been introduced in this paper,the power is estimated by accumulate the signal square value,then compare its logarithmic value to the reference and translate the difference into control word of the DVGA IC.The whole process is completed by software and the executor is DVGA IC AD8370.The results of simulate and practically test indicate that this method can respond quickly to the power change of input signal with high precision.so it is a feasible implement with FPGA and the dynamic range can reach 70dB。