射频宽带放大器的设计

Design of a RF Wideband Amplifier

系统由前级放大模块、后级放大模块、滤波模块组成。采用可控增益放大器AD603和宽带低噪声运放OPA690级联,很好地实现了0~60,d B增益可调的要求。电路整体设计利用可调电位器控制两级级联压控,可变增益放大器完成对放大器增益的调节,又通过滤波电路实现了选频。系统还采用自动直流偏移调零模块,最大限度地减小了整个放大器的偏移,使用了各种抗干扰措施以减少噪声并抑制高频自激。该放大器电路结构简单、性能稳定、功能完善,基本达到了各种设计指标的要求。

The system consists of pre-amplification module, stage amplifier modules and filter modules. The creative use of controllable gain amplifier AD603 and wideband low-noise op amp OPA690 cascade has achieved the requirements of adjustable gain between 0~60 dB. Overall circuit design uses adjustable potentiometer to control two cascaded controlled variable gain amplifier to adjust the gain of amplifier, and uses filter circuit to realize frequency selection. The system also uses an automatic DC offset nulling module to max. reduce the deviation. A variety of measures were used to reduce noise and interference and suppress high-frequency self-excitement. The amplifier circuit structure features simple structure, stable performance, complete functions and has basically reached the requirements of various design specifications.