针对重大自然灾害中大尺度区域应急通信需求,设计了一种高集成度的数字短波广播(Digital Radio Mondiale,DRM)发射系统。为实现高集成度和设计灵活性,采用片上系统(System on Chip,SoC)结构,将基带信号与上变频芯片进行耦合设计,利用硬...针对重大自然灾害中大尺度区域应急通信需求,设计了一种高集成度的数字短波广播(Digital Radio Mondiale,DRM)发射系统。为实现高集成度和设计灵活性,采用片上系统(System on Chip,SoC)结构,将基带信号与上变频芯片进行耦合设计,利用硬件电路的高速数据处理能力完成多载波调制,并利用软件设计的灵活性在单芯片上生成基带信号。采用Zynq-7020开发板,搭建基带信号调制系统,设计了无线传输整体硬件电路。在提高发射系统集成度的基础上,还具有发射频点可重构的优点,以有效应对短波频率选择性衰落。理论分析与仿真结果表明,基于SoC结构的DRM调制系统可以正确稳定输出用于上变频的器件的基带I/Q信号,具备较高的工程价值。展开更多
a method is proposed to improve the performance of MC-2D-CDMA in frequency selective fading channel. Each chip of spreading spectrum sequence is contained in two sub-carriers, so when fading is deep in one sub-carrier...a method is proposed to improve the performance of MC-2D-CDMA in frequency selective fading channel. Each chip of spreading spectrum sequence is contained in two sub-carriers, so when fading is deep in one sub-carrier, the other will compensate and the performance of this model is improved in frequency selective channel. Orthogonal restore combination (ORC) is used to explain the method. Computer simulation is used to exam the relation of signal noise ratio (SNR) and probability of bit error (BER), and the number of subscribers and BER. Then performance is compared among MC-2D-CDMA, MC-DS-CDMA and MC-CDMA.展开更多
文摘针对重大自然灾害中大尺度区域应急通信需求,设计了一种高集成度的数字短波广播(Digital Radio Mondiale,DRM)发射系统。为实现高集成度和设计灵活性,采用片上系统(System on Chip,SoC)结构,将基带信号与上变频芯片进行耦合设计,利用硬件电路的高速数据处理能力完成多载波调制,并利用软件设计的灵活性在单芯片上生成基带信号。采用Zynq-7020开发板,搭建基带信号调制系统,设计了无线传输整体硬件电路。在提高发射系统集成度的基础上,还具有发射频点可重构的优点,以有效应对短波频率选择性衰落。理论分析与仿真结果表明,基于SoC结构的DRM调制系统可以正确稳定输出用于上变频的器件的基带I/Q信号,具备较高的工程价值。
文摘a method is proposed to improve the performance of MC-2D-CDMA in frequency selective fading channel. Each chip of spreading spectrum sequence is contained in two sub-carriers, so when fading is deep in one sub-carrier, the other will compensate and the performance of this model is improved in frequency selective channel. Orthogonal restore combination (ORC) is used to explain the method. Computer simulation is used to exam the relation of signal noise ratio (SNR) and probability of bit error (BER), and the number of subscribers and BER. Then performance is compared among MC-2D-CDMA, MC-DS-CDMA and MC-CDMA.
