中文摘要：

为了精确控制直接数字合成（DDS）信号源输出信号幅度值，利用亚德诺（ADI）公司的高性能芯片AD8368设计了增益自动调整电路和可变增益放大电路。实现将DDS芯片产生的不同幅值正弦信号通过增益自动调整电路后，变化为同一幅度值正弦信号，再通过可变增益放大电路完成输出正弦信号幅度值0.2～2V程控可调。该设计结构简单、集成度高，经测试性能良好。

英文摘要：

In order to accurately control the output signal amplitude values of DDS signal generator,the automatic gain control circuit and variable gain amplifier circuit is designed by using ADI company’ s high-performance AD8368 chip-The different amplitude sine signal generated from DDS chip becomes the same amplitude sine signal through the automatic gain control circuit,the amplitude values is adjusted from 0.2-2 V through variable gain amplifier circuit-This design has simple structure,high integration and better performance proved by the test.