Design Of Broadband RF Transceiver Front-end System

Radio is the main means of military communication.Countries also focus on the developing of military field communications technology.The environment that Military radio works is bad.There are a lot of electromagnetic interference that requires high precision,strong anti-interference,high sensitivity,and wide dynamic range of transceiver.The performance of transceiver RF front-end is also significantly influenced the quality of signal communication.States focus on the research and development of better performance transceiver in the field of military communications research.This paper investigates the classic structure of a transceiver design,and analyzes the advantages and disadvantages of various structures.The use of precise RF matching and optimization of the structure of the receiver could improve the shortcomings that present in domestic transceiver design.This paper makes the final design of the system,and gives the practical design of conversion module,AGC module,FPGA logic control module.In the design,in order to match the channel within wideband range,RF filter and amplifier module using multi-stage filter and the way of sub-band processing using FPGA automatic control band selection.These could get the optimization of the signal in the RF stage.The design of receiver is double-conversion superheterodyne structure.The selection of high-frequency in first IF provide inhibition rate of the image signal.A low intermediate frequency in second IF could help select and obtain signal gain.Using FPGA overall automatic control could adjust the transceiver to work at any time based on the received signal.The work of the RF transceiver front-end was controlled by FPGA.The control includes the exchange of information with baseband,the frequency hopping and the band selection.The FPGA controls can increase the flexibility of the transceiver as well as the ability to adapt to the environment.Through testing various key RF front-end transceiver module and overall system performance,we make improvement to optimize the design.Through test the transceiver in high precision frequency on 30 MHz?512MHz wideband,we the performance of 110 dB dynamic range,-115 dB sensitivity,-40?0 dB IF gain.The performance meets the requirements of initial design.The design covers all key modules of the transceiver RF front-end.The design make contribution to the spread spectrum radio designed for the next segment.