学科分类
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4 个结果
  • 简介:Cyclostationary健全的地是nonstationary声音地,压力信号严重在被调制的一种特殊类型,边带在它的光谱存在。重建的健全的地不能在常规Nearfield声学的雷射摄影术考虑cyclostationary特征(不)过程。根据平面cyclostationary不,cyclostationary不基于边界元素方法被建议它能被利用与复杂表面分析散热器。用秒顺序代替Fourier的变换周期的统计,周期光谱密度(CSD)功能被用作重建的物理数量在不建议了技术,而不是光谱或力量光谱压力的密度信号。由CSD功能的解调能力的优点,重建的CSD能有效地分别地表示modulating和搬运人波浪的信息。模拟和实验说明这cyclostationary的有效性和精确性不技术满足工程的请求。

  • 标签: 声音场 压力信号 声音全息术 傅里叶变换
  • 简介:Higher-orderalmostcyclostationarycomplexprocessesarecomplexrandomsignalswithalmostperiodicallytime-varyingstatistics,whichisimportanttotheresearchofnon-Gaussiansignalsininformationsystem.Intinspaper,smoothedpolyperiodogramsareproposedforrelatedtocyclicpolyspectralestimationandareshowntobeconsistentandasymptoticallycomplexnormal.Asymptoticcovarianceexpressionsarederivedalongwiththeircomputableforms.

  • 标签: COMPLEX CYCLOSTATIONARY SEQUENCES NONPARAMETRIC cyclic-polyspectrum estima-tion
  • 简介:Onenearfieldacousticholography(NAH)techniqueisproposedforanalyzingcyclostationarysoundfield.Thesignalofthiskindofsoundfieldhasveryseriousmodulationphenomenongenerally,inspectrumofwhichobvioussidebandsexist.ItisdifficultforthetraditionalNAHtopossessdemodulationfunction,sovirtualpowerofsidebandsexistsinitshologram.ReplacingtheFourier'stransformwiththesecond-ordercyclicstatistics,theproposedNAHtechniqueusesthecyclicspectrumdensity(CSD)functionasreconstructedphysicalquantity,insteadofthespectrumorpowerspectrumdensityofsoundpressuresignal.TheCSDfunctioncandemodulatecyclostationarysignals,whichmakesnovirtualpowerofsidebandsinitshologram.TheresultsofsimulationandexperimentshowthattheproposedNAHcanextractmoreinformationaboutcyclostationarysoundfieldthantraditionalNAH,bywhichsoundfieldcanbeknownmoreclearly.

  • 标签: 近场声学全息摄影 旋衡声场 试验设计 循环声谱密度函数
  • 简介:Oneofthemainrequirementsofcognitiveradiosystemsistheabilitytodetectthepresenceoftheprimaryuserwithfastspeedandpreciseaccuracy.Toachievethat,apossibletwo-stagespectrumsensingschemeissuggestedinthispaper.Morespecifically,afastspectrumsensingalgorithmbasedontheenergydetectionisintroducedfocusingonthecoarsedetection.Acomplementaryfinespectrumsensingalgorithmadoptsone-ordercyclostationarypropertiesofprimaryuser'ssignalsintimedomain.Sincetheone-orderfeaturedetectionisperformedintimedomain,thereal-timeoperationandlow-computationalcomplexitycanbeachieved.Also,itdrasticallyreduceshardwareburdensandpowerconsumptionasopposedtotwo-orderfeaturedetection.Thesensingperformanceoftheproposedmethodisstudiedandtheanalyticalperformanceresultsaregiven.Theresultsindicatethatbetterperformancecanbeachievedinproposedtwo-stagesensingdetectioncomparedtotheconventionalenergydetector.

  • 标签: 循环平稳特性 无线电系统 检测技术 特征检测 能量检测 一阶