In radio receivers,complete implementation of the software defined radio(SDR) concept is mainly limited by frontend.Based on bandpass sampling(BPS) theory,a flexible digital frontend(DFE) platform for SDR receiver is ...In radio receivers,complete implementation of the software defined radio(SDR) concept is mainly limited by frontend.Based on bandpass sampling(BPS) theory,a flexible digital frontend(DFE) platform for SDR receiver is designed.In order to increase the processing speed,Gigabit Ethernet was applied in the platform at speed of 5×10~8 bit/s.By appropriate design of interpolant according to the position of input RF signals,multi-band receiving can be realized in the platform with suppression more than 35 d B without changing hardware.展开更多
为有效检测树干分层介质厚度和相对介电常数,该研究提出一种基于雷达探测的树干分层结构介电参数反演方法。基于斯涅耳定律结合树干生理结构特点,构建雷达信号在树干分层结构中的传播模型。利用软件定义无线电平台(software defined rad...为有效检测树干分层介质厚度和相对介电常数,该研究提出一种基于雷达探测的树干分层结构介电参数反演方法。基于斯涅耳定律结合树干生理结构特点,构建雷达信号在树干分层结构中的传播模型。利用软件定义无线电平台(software defined radio,SDR)搭建树干探测雷达。然后采用稀疏分解算法、K-SVD字典训练以及层剥离算法对探测雷达回波信号进行参数反演,并对不同的稀疏分解算法反演结果进行了对比。试验表明在回波混叠和无混叠的情况下,该方法均能够对树干分层介质厚度和相对介电常数进行估算;无混叠时相对介电常数和厚度的反演误差分别在2.93%和3.5%以内,混叠时相对介电常数和厚度的反演误差分别在7.52%和7.61%以内。综合试验结果表明,在5种反演算法中,SAMP算法在未知信号稀疏度的条件下表现最佳,具有较高的反演准确率和鲁棒性。展开更多
针对软件通信架构(Software Communication Architecture,SCA)核心框架在机载领域臃肿和低效等问题,提出了一种面向机载软件无线电(Software Defined Radio,SDR)系统的SCA核心框架优化方案。首先,为使架构轻量高效,提出功能单元裁剪方法...针对软件通信架构(Software Communication Architecture,SCA)核心框架在机载领域臃肿和低效等问题,提出了一种面向机载软件无线电(Software Defined Radio,SDR)系统的SCA核心框架优化方案。首先,为使架构轻量高效,提出功能单元裁剪方法;其次,针对时间优化问题,分析了SCA的局限性,提出可灵活配置的加载流程优化技术,在兼容SCA规范的基础上可根据实际系统特点实施灵活的组件加载,充分发挥系统的并行加载潜力来缩短加载时间。实验结果表明,所提的优化技术能够有效提升SDR系统可用性,对面向机载SDR系统的SCA架构优化设计和应用具有较强的指导意义。展开更多
Some structures of digital quadrature AD conversion for soft-ware-defined radio （SDR） systems are studied. Their performances and affections on the SDR systems are also analyzed. Two generalized quadrature AD scheme...Some structures of digital quadrature AD conversion for soft-ware-defined radio （SDR） systems are studied. Their performances and affections on the SDR systems are also analyzed. Two generalized quadrature AD schemes are proposed. In one of them, the AD sampling speed can be reduced by 2 times; and in the other both the output data rate of every channel and AD sampling speed can be lowered by paralleling the digital quadrature filtering structure. These structures can be also easily implemented into modules, and the polyphase filters can be flexibly realized by VHDL language based one chip of FPGA. To assess the proposed schemes, their applications to a particular ultra wideband （UWB） demonstrative receiver system are introduced. Some experimental results are also given. It is shown that the generalized quadrature AD structures are reliable and feasible for its module design, and performances are improved obviously for its better performance to price ratio.展开更多
基金Project(2013QNA49)supported by the Fundamental Research Funds for the Central Universities,China
文摘In radio receivers,complete implementation of the software defined radio(SDR) concept is mainly limited by frontend.Based on bandpass sampling(BPS) theory,a flexible digital frontend(DFE) platform for SDR receiver is designed.In order to increase the processing speed,Gigabit Ethernet was applied in the platform at speed of 5×10~8 bit/s.By appropriate design of interpolant according to the position of input RF signals,multi-band receiving can be realized in the platform with suppression more than 35 d B without changing hardware.
文摘为有效检测树干分层介质厚度和相对介电常数,该研究提出一种基于雷达探测的树干分层结构介电参数反演方法。基于斯涅耳定律结合树干生理结构特点,构建雷达信号在树干分层结构中的传播模型。利用软件定义无线电平台(software defined radio,SDR)搭建树干探测雷达。然后采用稀疏分解算法、K-SVD字典训练以及层剥离算法对探测雷达回波信号进行参数反演,并对不同的稀疏分解算法反演结果进行了对比。试验表明在回波混叠和无混叠的情况下,该方法均能够对树干分层介质厚度和相对介电常数进行估算;无混叠时相对介电常数和厚度的反演误差分别在2.93%和3.5%以内,混叠时相对介电常数和厚度的反演误差分别在7.52%和7.61%以内。综合试验结果表明,在5种反演算法中,SAMP算法在未知信号稀疏度的条件下表现最佳,具有较高的反演准确率和鲁棒性。
文摘针对软件通信架构(Software Communication Architecture,SCA)核心框架在机载领域臃肿和低效等问题,提出了一种面向机载软件无线电(Software Defined Radio,SDR)系统的SCA核心框架优化方案。首先,为使架构轻量高效,提出功能单元裁剪方法;其次,针对时间优化问题,分析了SCA的局限性,提出可灵活配置的加载流程优化技术,在兼容SCA规范的基础上可根据实际系统特点实施灵活的组件加载,充分发挥系统的并行加载潜力来缩短加载时间。实验结果表明,所提的优化技术能够有效提升SDR系统可用性,对面向机载SDR系统的SCA架构优化设计和应用具有较强的指导意义。
基金This project was part financially supported by Natural Science Researching Project for Jiangsu Universities (03KJB510130, 05KJD510177 and NSFC.60572075).
文摘Some structures of digital quadrature AD conversion for soft-ware-defined radio （SDR） systems are studied. Their performances and affections on the SDR systems are also analyzed. Two generalized quadrature AD schemes are proposed. In one of them, the AD sampling speed can be reduced by 2 times; and in the other both the output data rate of every channel and AD sampling speed can be lowered by paralleling the digital quadrature filtering structure. These structures can be also easily implemented into modules, and the polyphase filters can be flexibly realized by VHDL language based one chip of FPGA. To assess the proposed schemes, their applications to a particular ultra wideband （UWB） demonstrative receiver system are introduced. Some experimental results are also given. It is shown that the generalized quadrature AD structures are reliable and feasible for its module design, and performances are improved obviously for its better performance to price ratio.
