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MIMO雷达需要正交线性调频连续波(LFMCW)信号源。针对传统方案无法产生严格正交信号、实现线性调频信号困难、系统干扰较多的问题,设计了基于DDS技术的MIMO雷达正交线性调频信号源。系统以FPGA为主控单元,采用AD9854为核心搭建控制模块,经差分放大电路进行信号调理,结合上位机最终实现输出1~40 MHz的频率可实时程控双路正交单频正弦信号、三角线性扫频信号。通过实验测试,输出频率达40 MHz,峰峰值达5 V,信号稳定度达10-4,信号模式灵活可调,满足正交LFMCW信号源的要求。 相似文献
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Butt joints of QCrO. 8/1Cr2lNiSTi equal-thickness dissimilar materials were obtained by electron beam welding with fixed accelerating voltage 60 kV and focus current 1.99 A, changed electron beam current and welding velocity. Microstructure and composition of the EBW joint were investigated by means of optical micrography and EDX analysis, mechanical properties of the joint were also tested. The results show that joint‘ s macrostructure was divided into three zones : top weld zone near QCrO. 8 and bottom weld zone consisting of Cu (ss. Fe ) with a certain amount of dispersedly distributed (α ε) mixed microstructure , middle weld zone consisting of (α ε ) microstracture with a small amount of Cu (ss. Fe )particles. Morphological inhomogeneous macrostructure and uneven chemical compostion of QCrO. 8/1Cr21NiSTi joint by EBW are the most important factor to result in decreasing joining strength. 相似文献
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0 IntroductionThedissimilarmaterialsjointisusuallyemployedinindustrialproductiontomakefulluseofthematerialsperformanceadvantageorspecialstructuralpurpose.Thedissimilarmaterialsjoiningtechnologybetweencopperalloyandstainlesssteelhasattractedagreatdealofattention,botheffectiveassemblageputweldedcomponent’scoolingandhighstrengthintoeffect.However,becauseofbothmaterialschemicalandthermophysicalperformancedifferenceandcomplexityofweldingmetallurgy,thedefectsuchaspore,crackandbrittlephaseandarathe… 相似文献
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为有效解决大面积环境模拟参数采集难、采样精度不足、长距离传输信号不稳定的难题,设计了分布式远程模拟量数据采集系统,系统由上位机、背板、总节点和分节点4部分组成,基于RS485总线建立有线数据采集网络,FPGA为主控芯片,高精度采集芯片ADS1258为模数转换模块。文中设计适用于采集范围分散,精度要求高,传输距离较远的应用场合,结果表明,采集系统能够在大范围,多点处采集得到精确的环境模拟量,并具备远距离传输抗干扰能力,符合设计要求,已成功应用于某测试场。 相似文献
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为了对导弹引信滑轨实验中各路信号进行高速记录、存储,设计了多通道高速滑行数据记录设备,该系统主要由记录设备、远程读数装置及数据分析软件组成,记录设备以FPGA为控制单元,分别对引信的遥测信号和信噪比信号进行实时并行接收,经FPGA进行数据混合编帧后存储在FLASH芯片中,该存储过程采用2级片外流水线页编程技术提高存储速度,装 置回收后,上位机采用多线程技术高速读取数据并进行分析,经过测试,该记录设备在复杂环境下能够准确接收各类数据,FLASH存储速率达到15Mbyte/s,上位机读取速率达到16.5Mbyte/s,数据回放完整,已应用于某导弹引信滑轨实验中。 相似文献