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A method of multi-channel receiving for high bit rate heterodyne direct-detection optical orthogonal frequency-division-multiplexing (OOFDM) system is proposed to reduce the sampling rate demand of analog-to-digital converter (ADC). The sampling rate of ADCs can be reduced to 1/N that of the original signal bandwidth in an N-channel receiving system. Aided by a succeeding digital signal processing (DSP) at the receiver, aliasing free signal can be recovered. A back-to-back experimental result is given for a 4-channel system, based on which, a down conversion process for heterodyne can be reduced. The signal rebuilding algorithm is given and analyzed in its complexity and noise tolerance. 相似文献
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<正>A cost-effective method of multi-receiver optical orthogonal frequency-division multiplexing(OOFDM) system is proposed to reduce the requirement for the speed of the receiver and the size of fast Fourier transform(FFT).The sampling rate of analog-to-digital converters(ADCs) can be reduced to 1/N of the original signal bandwidth in an N-receiver system.Aided by signal predistortion at the transmitter, aliasing-free signal can be retrieved independently and directly at the low speed receivers.A back-to-back experimental result is given for a two-receiver system.The effect of the electrical filters added before the ADC is studied and the analysis for filters optimization is given. 相似文献
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通过2,2',6,6’-联苯四酸与相应金属硝酸盐和第二配体的水热反应合成了2个具有不同结构的配位聚合物[Co(bta)0.5(2,2’-bipy)(H2O)]n(1)和{[Cd2,(bta)(H2biim)2(H2O)]·H2O}n(2)(H4bta=2,2’,6,6’-联苯四酸,2,2'-bipy=2,2’-联吡啶,H2biim=1H,1’H-2,2’-联咪唑),并测定了其晶体结构.1和2都是一维链结构,并且1和2都属于单斜晶系,P21/c空间群.bta配体在1和2中分别采取η6,μ4六齿和η5,μ4-五齿配位模式,同时bta配体中2个苯环的夹角在化合物1和2中分别是64.80°和64.86°.1与2分别在170℃和120℃以下保持热稳定性. 相似文献
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环路热管吸液芯毛细抽吸特性研究 总被引:1,自引:0,他引:1
采用计算机记录毛细抽吸量实时变化曲线的方法,研究了环路热管吸液芯对不同工质的毛细抽吸特性,结果表明所有的吸液芯毛细抽吸过程均可分阶段采用玻耳兹曼方程进行描述,其误差在启动阶段和稳健抽吸阶段分别在5%和1%以内。工质的表面张力越大、密度越大,吸液芯的毛细抽吸量就越大;工质的表面张力越大、黏度越小,毛细抽吸速度越大。对孔隙率为45%~56%的吸液芯进行毛细抽吸实验发现,随着孔隙率的增大,抽吸速度和毛细抽吸量均随之增大,可见适当提高吸液芯的孔隙率有助于提高环路热管的性能。 相似文献
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