基于AD8368芯片的压控增益放大系统设计分析

针对接收机中信号电平变化范围过大所导致的系统恶化问题,提出基于中频信号检测电压反馈,2级AD8368芯片级联构造具有70 dB动态范围的中频大动态自动增益控制(AGC)的方法。对自闭环控制电路进行了分析,证明该方法能够解决宽动态范围下信号增益自动控制问题,实现了快速、稳定的自动增益控制,从而保证接收机小信号下的高灵敏度,提高系统的接收灵敏度。

Design and Analysis on VGA System Based on AD8368

To solve the system performance deteriorating problem caused by too lar ge variable range of signal power in receiver,this paper proposes an IF large d ynamic automatic gain control method with 70dB dynamic range based on IF signal detection voltage feedback and 2-stage AD8368 chip cascade structure.The analys is on closed loop control circuit proves that this method can solve the automati c control problem of signal gain within wide dynamic range,achieve fast,stable and automatic gain control,ensure high sensitivity of receiver under small sig nal conditions and improve the system of received sensitivity.