GPS双频M码接收机射频前端 设计与实现

介绍了GPS信号体制、新型军用M码的产生方式及其特点,并将新型M码信号与传统GPS信号做了对比。采用超外差式结构分离元器件方案完成了系统的设计并给出了组成原理框图。然后对原理框图中每一个功能单元的电路实现进行了设计,合理选择了低噪声放大器、功分器、射频滤波器、射频放大器、混频器、本振发生器、中频滤波器、中频放大器、数控衰减器、末级放大器等,根据选择的器件完成了原理图以及PCB设计,并为系统设计了屏蔽盒。最后对系统相应的指标进行了测试,测试结果表明该射频前端达到了要求的技术指标。

Design and Realization of RF Front-end of M Code GPS Dual-frequency Receiver

RF front-end of M Code GPS Dual-frequency Receiver is designed and realized in this paper. Firstly, the traditional GPS signal system, the generation method of new military M code and its characteristic, and differences between the new M code signal and the traditional GPS signals are introduced. The scheme of separation components with superheterodyne structure is selected to complete the system design and the functional block diagram is given. Then the circuit implementation of each functional units in the functional block diagram are analyzed and designed by reasonable selections of low noise amplifier, power splitters, RF filter, RF amplifier, mixer, the vibration generator, intermediate frequency filter, intermediate frequency amplifier, digital control attenuator, final stage amplifier and so on. The schematic and PCB design are completed based on the selected devices, and the shielding box is designed for the system. The corresponding indexes of system are tested at the end; results show that the RF front-end meets the requirements.