简介：测量信号的振幅是在纤维布拉格的波长解调的平常的方法栅栏(FBG)传感器最近。这个方法是容易的被扰乱并且让低精确。在这份报纸，FBG传感器使用的一个新奇数的波长解调计划一面高双折射的纤维(HBF)环镜子被报导。这个解调器有简单结构，高精确，便宜价格和方便使用。有30米的HBF的环镜子设备的分辨率长是0.067nm。为大约1550nm的FBG和它的思考波长的40nm移动范围的中心波长，测量的相对错误仅仅是卤0.001。这台波长解调设备为FBG传感器的普遍申请有意义。CLC数字TP212.14

简介：为3的修改解调算术??????铻???鲳鶣???鰿D

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简介：到识别问题的轮船噪音解调光谱泛音氏族特征和相应应用的结构法律被理论推导和样品分析学习。以便认出推进器片数字，轮船推进器成穴噪音模型根据五个假设被建立。进一步，结构法律的数学表达式被模型推出。并且推进器片数字的类空格算术地被分析。结果能被使用作为专家知识指向识别。最后，实验样品的解调光谱泛音氏族被使用小浪包获得。结构法律被实验样品的统计分析验证。实验样品的统计平均结果与理论结构法律一致很好，这被显示出，并且78.6%样品基本上与理论结构法律一致。

简介：一个修改基因算法(GA)被建议了，它在察觉到系统的伪静电干扰纤维栅栏习惯于波长解调。GA的修正方法被介绍了，相关数学模型被建立了。客观功能和与GA互连的单个健康评估策略也被建立。GA上的人口尺寸，染色体尺寸，代，转线路概率和变化概率的影响被分析了，并且修改GA的最佳的参数被获得了。模拟和实验，修改GA能被用于察觉到系统的伪静电干扰纤维栅栏的表演，和精确是的波长解调平等者到或不到3下午。CLC数字TN253

简介：Tosolvebladenumbercharacteristicextractionproblemoflownoiseships,phasecharacteristicsofshipradiated-noisedemodulationspectrumharmoniccomponentsusinghigherorderspectrumanalysiswereconsidered.Throughanalyzingalargenumberofshipradiatednoisedata,itpointsouttheexistingphasecouplingrelationshipbetweentwoorthreeharmoniccomponentsofdemodulationspectrum.Thephasedifferencebetweenlinespectrumofbladefrequencyandthesumoflinespectrumatshaftfrequencyanditssomeharmoniccommonlyiszeroorotherconstant.Higher-ordercumulantisgivenandhigher-orderspectrumissimulatedwhenabovephasedifferenceisanon-zeroconstant.Theapplicationofphasecouplingrelationshipisstudied.Accordingtothehigher-orderspectralanalysisofsomeweakmodulatedshipradiatednoise,itisindicatedthatthephasecouplingrelationshipandhigher-orderspectralanalysiscanimprovetheabilitytoextractpropellerparameters,especiallyfortheweakmodulation.

简介：AbstractObjective:To investigate the efficacy of in-phase and quadrature (IQ) demodulation in electronic fetal heart rate monitoring (EFM) to reduce false reports of fetal heart rate (FHR) doubling or halving.Methods:This is a prospective cohort study. A total of 263 full-term pregnant women who delivered at Peking University Shenzhen Hospital between August 2019 and July 2020 were prospectively enrolled in the study. FHR monitoring began when the cervix was dilated to 2-3 cm and continued until delivery. Raw fetal Doppler audio signals and internal and external cardiotocography curves from internal electrode monitoring, EFM with conventional demodulation (external), and EFM with IQ demodulation (external) were acquired to compare FHR doubling and halving time. In cohort 1, FHR was compared between IQ demodulation and conventional demodulation. In cohort 2, FHR was compared between IQ demodulation, conventional demodulation, and internal FHR monitoring. Count data were statistically analyzed using the Chi-squared test, and measurement data were statistically analyzed using t-test for correlation coefficients, and Bland-Altman analysis for concordance ranges.Results:To compare IQ demodulation and conventional demodulation, 225 pregnant women were monitored for a total of 835,870 seconds. The beat-to-beat interval of FHRs in raw fetal Doppler audio signals was used as the reference. The results showed a doubling time of 3401 seconds (0.407%, 3401/835,870) and a halving time of 2918 seconds (0.349%, 2918/835,870) with conventional demodulation, compared to 241 seconds (0.029%, 241/835,870) and 589 seconds (0.070%, 589/835,870), respectively, with IQ demodulation. IQ demodulation reduced FHR doubling by approximately 93% (3160/3401) and FHR halving by approximately 80% (2329/2918) compared to conventional demodulation (P < 0.01).To compare IQ demodulation, conventional demodulation, and internal FHR monitoring, 38 pregnant women were monitored for a total of 98,561 seconds. FHR from internal electrode monitoring was used as the reference. The results showed a doubling time of 238 seconds (0.241%, 238/98,561) and a halving time of 235 seconds 0.238%, 235/98,561) with conventional demodulation, compared with 30 seconds (0.030%, 30/98,561) and 81 seconds (0.082%, 81/98,561), respectively, with IQ demodulation (P < 0.05). No significant difference was observed in doubling or halving time between IQ demodulation and internal FHR monitoring (P > 0.05). IQ demodulation was more closely correlated with internal FHR monitoring than conventional demodulation (0.986 vs. 0.947). The Bland-Altman analysis showed that the concordance range of IQ demodulation vs. internal FHR monitoring was significantly narrower than that of conventional demodulation vs. internal FHR monitoring ((-5.32,6.01) vs. (-10.87,11.46)).Conclusion:EFM with IQ demodulation significantly reduces false FHR doubling and halving, with an efficacy similar to that of internal FHR monitoring.

简介：Anovelfibergratingvibrationdemodulationsystem,basedon2×2and3×3couplers,isdesigned.Basedonthephaseunwrappingalgorithm,thethree-wayasymmetricaloutputofthe3×3coupleranddemodulationstatecharacteristicsofthesystemwhenthevibrationsignalincludeshighharmonicwavesareanalyzedinsimulations.Theresultshowsthatwhenthethree-wayoutputisasymmetrical,themaximumdeviationofdemodulationsignalis1.625%,andwhenthevibrationsignalincludeshighharmonicwaves,themaximumdeviationofdemodulationsignalis0.9%.Thecorrespondingexperimentisconducted.Theexperimentalresultshowsthatthedynamicresolutionofthesystemis25.22nε/Hzwhenthevibrationpitchis5.5Hz.

简介：WeproposeaschemeformitigatingRayleighbackscatteringnoiseanddemodulatingdifferentialphaseshiftkeying(DPSK)signalsinwavelength-division-multiplexedpassiveopticalnetworks(WDM-PONs)withinjection-lockedFabry-Perotlaserdiodes(FP-LDs).SignaldemodulationandwavelengthconversionaresimultaneouslyrealizedonthebasisofthefrequencydeviationandredshiftoflongitudemodesintheFP-LDs.Experimentalresultsdemonstratethatthedemodulationandwavelengthconversionof2.5-Gb/sDPSKsignalsareachieved.Apowerpenaltyofabout1.6dBatabiterrorrateof109ismeasuredaftertransmissionover25-kmsinglemodefiber.