Research And Validation On Key Technology Of 3GHz Bandwidth Coaxial Access Network RF Circuits

As an important part of the communication system,the coaxial access network communication has the advantages of fast data transmission rate,strong anti-jamming ability,safety and reliability,and has gained extensive attention from researchers.The coaxial access network will continue to broaden the frequency band in order to further improve the transmission performance.This will also lead to some technical challenges in RF circuits: the equalization for the coaxial attenuation and the nonlinear suppression of ultra-wideband RF circuits.This paper studies and verifies the key technologies of the 3GHz ultra-wideband coaxial access RF circuit based on the current development trend of the coaxial access network.First,this paper introduces the development status and evolution direction of the most representative Data Over Cable Service Interface Specifications in the coaxial access network technology.The common structures of the coaxial access RF circuit are introduced,and the advantages and disadvantages of each structure is analyzed.Combined with the development trend of access technology and project conditions,the RF direct sampling structure is selected for circuit design.Secondly,according to the application scenario of wideband coaxial access network,the technical indicators for downlink RF transceiver circuits are formulated,including modulation error rate more than 40 d B,gain equalization amount 19 dB,transmit circuit output power greater than 20 dBm,and receiving circuit noise figure less than 4dB and so on.The key indicators of the RF circuit are deduced theoretically and the factors influencing the performance are analyzed.Thirdly,based on the key technical indicators,the overall design and detailed design of the 3GHz broadband coaxial access RF downstream transceiver are done,including the structure of the transceiver circuit,the selection of key devices,the link budget,and the key circuit module design and the PCB design.Finally,complete the circuit board production and performance debugging.We build a test platform to test and verify the key indicators of the RF transceiver circuit.The results of the test are analyzed,and the future work and suggestions are given.The paper designs and implements a set of 3GHz broadband coaxial access RF transceiver circuit.After testing,the circuit performance indicators meet the requirements of the coaxial access network application scenario.Can achieve 19 dB gain equalization in the range of 0.3-1.9GHz frequency band and the modulation error rate of the transceiver circuit is greater than 40 dB,providing a reference for the design of next-generation coaxial access network RF circuits.