基于RF接收机的过冲性能优化分析

Optimization Analysis of Overpulse Based on RF Receiver

可变增益控制是RF接收机的通用功能,它包括程控衰减器和放大器。可编程增益控制单元一般采用CMOS结构的开关器件。采用半导体制造技术制造的CMOS结构开关器件存在非理想特性,其中开关切换过程残留电荷是一种非理想特性。如果CMOS开关器件位于信号通路,开关切换残留电荷会传导到下一级电路,从而影响系统的瞬态性能,干扰RF接收机对获取信号的判断。通过在技术上的设计来减小开关过冲是CMOS结构开关器件的设计难点之一。针对这一特性,进行了理论分析并提出了解决方案。通过对几种解决方案的对比,给出了各自的特点。最后通过差分抑制过冲的实测结果分析,表明此方法具备较优效果。

VGA（variable gain amplifier） is a universal module in RF receiver.It consists of programable attenuator and amplifier.Programmable gain control unit usually uses CMOS structure of the switch device.CMOS switches made by semiconductor fabrication technology have some non-ideal characteristics,and the residual charge of the switching process is one of non-ideal characteristics.If a CMOS switch device is located in the signal path,the switching residual charge will be transmitted to the next-stage circuit which affect the system transient performance,and interfere with the signal judgment of the RF receiver.The design to reduce the switching overshoot is one of the difficulties of the CMOS structure design on the switching devices.For this feature,the amplitude and frequency analysis were carried out,and the solutions were proposed.Comparison of several solutions,characteristics of each were given.Finally,the results of differential characteristics to suppress overshoot show that this method has the better effect.