共查询到17条相似文献,搜索用时 500 毫秒
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光载射频(ROF)通信系统已经成功应用于移动通信系统、智能交通控制、室内信号的覆盖等众多领域。毫米波生成技术作为ROF的关键技术,得到了很大的发展,基于外部调制技术、光外差技术和上变频技术的新方案不断地涌现。从ROF的原理着手,研究了整个系统中毫米波生成的几种常见方法,对其优缺点进行了分析,最后简单介绍了ROF的应用领域。 相似文献
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基于光学倍乘法产生光毫米波的全双工毫米波光纤传输系统设计 总被引:2,自引:0,他引:2
毫米波光纤(ROF)传输系统中当采用强度调制器直接调制毫米波信号时,随着传播距离的延长会产生信号强度的周期性衰落问题,限制了毫米波通信技术的发展.光学倍乘法(OFM)将低频或中频调制信号搭载在扫频光信号上,通过在基站生成毫米波的方法,有效缓解信号强度的周期性衰落,具有广阔的发展前景.提出并实验研究了一种基于光学倍乘法产生光毫米波的全双工毫米波光纤传输系统.系统中利用光纤Bragg光栅提取光波作为上行链路光载波,基站中不需配置光源,而且对光功率的损耗小,合理利用了资源.基站中还采用低频本振与毫米波载波混频的方法实现上行链路本振,解决了上行链路本振的生成难题,方法简单,成本低廉,有利于简化基站,降低成本. 相似文献
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基于ROF系统的光学倍频技术分析 总被引:1,自引:1,他引:0
光学倍频法(OFM)在低频电信号的驱动下可借助光电子器件的非线性调制获得满足光纤无线系统(ROF)应用要求的高频毫米波,是一种行之有效的光生毫米波方法。文中首先对基于铌酸锂马赫-曾德尔调制器(LN-MZM)的OFM产生高频毫米波的理论公式进行了推导,然后在此基础上对LN-MZM处于不同消光比和偏置条件下的光生毫米波过程进行了理论仿真。仿真结果表明了借助LN-MZM的OFM产生高频毫米波的有效性。 相似文献
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对ROF(radio over fiber,光载射频)系统在应用过程中的调制方式进行了分析,同时通过一系列实验证明单边带调制更适合应用于ROF系统的通信过程。因此,基于闪耀光纤光栅(TFBG,tilted fiber bragg grating)的复耦合模理论对光栅的谱的性能进行了分析和实验,不难发现,经过对TFBG进行特定的设计后,可以将TFBG应用于ROF系统中对双边带信号进行反射或者透射实现单边带调制,这样既减少了输出振幅随着距离的周期性变化,也提高了信号的传输效率和接收灵敏度。 相似文献
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提出了一种基于光载无线(ROF)技术的W波段涡旋毫 米波生成及轨道角动量(OAM)多维联合调制 /解调方法。采用ROF技术在光域对微波源进行倍频生成W 波段光学毫米波,并通 过集成光调制 器对光学毫米波的相位和幅度进行调控。通过合理调控圆环天线阵列(CAAs)的辐射毫米波 相移,从而实 现涡旋毫米波的生成以及状态切换。同时,设计了64阶OAM、幅度和 相位的三维联合调制格式, 并通过模拟仿真,成功实现了75Gbit/s高阶联合调制信号的调制/解 调。研究结果表明,OAM 作为一个新 的物理维度不仅可以通过复用来实现传输容量密度的提升,同时也可以作为调制手段实现 传输容量的提 升,在提高无线频谱效率以及保密通信中具有重要的潜在应用价值。 相似文献
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射频光纤传输系统中色散对数字毫米波信号的影响 总被引:1,自引:0,他引:1
给出了通过采用双边带调制技术来产生下行链路的ROF毫米波数字信号的设计方法:同时对基于数字ROF信号的光纤传输系统的色散影响进行了理论分析和仿真。仿真结果表明:由于光纤色散影响,毫米波信号的接收功率会随传输距离的变化而成周期性的衰减;同时对传输特性影响较大,而且当常规单模光纤中的传输达到90公里以后,还会产生比较严重的影响。 相似文献
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Yong Zhang 《中国电子科技》2011,9(1)
Millimeter-wave radio-over-fiber technology demonstrates the potential for providing wireless broad-band service in the next generation wireless communication system.Optical generation of millimeter-wave signal is one of the most important technologies of millimeter-wave radio-over-fiber system.The virtues and shortcomings of some ways of optical generation of millimeter-wave signal are discussed.Then optical millimeter-wave signal transmission performance is described.Finally,an overview of the millimeter-wave radio-over-fiber system is given.It is suggested that the millimeter-wave radio-over-fiber technology should be paid more attention,especially for modulators for optical generation of millimeter-wave signal and radio-over-fiber system. 相似文献
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Generation and transmission of millimeter-wave data-modulated optical signals using an optical injection phase-lock loop 总被引:1,自引:0,他引:1
Generation and transmission of millimeter-wave data-modulated optical signals is presented using an optical injection phase-lock loop (OIPLL). Millimeter-wave signal generation is demonstrated with wide locking range, 30-GHz low phase noise level, -93 dBc/Hz, and a wide frequency tuning range, 4-60 GHz generation demonstrated using optical injection locking only, verified by using OIPLL in the 26-40 GHz range. The OIPLL is also used to transmit error-free 140-Mb/s amplitude shift keying and 68-Mb/s differential phase-shift keying (DPSK) modulated millimeter-wave signals over up to 65 km of uncompensated standard singlemode fiber. The DPSK system uses reference frequency modulation, eliminating the need for optical amplification. 相似文献
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We have experimentally investigated two different schemes (schemes A and B) to generate optical millimeter-wave using optical frequency quadrupling with a Mach–Zehnder modulator (MZM), and wavelength reuse for uplink connection in the radio-over-fiber (ROF) systems. For scheme A, only one MZM is used for both the optical millimeter-wave generation and signal modulation. For scheme B, two MZMs are used. In this scheme, one of MZMs is used to generate optical millimeter-wave for frequency quadrupling, and another one is used for signal modulation. In both schemes, at the base station (BS), the optical carrier can be reused to carry upstream data and delivered to the central station (CS). By experimentally comparing the performance of downstream and upstream transmission in two schemes, it can be seen that scheme B can overcome the crosstalk between the upstream and downstream signals, but scheme A cannot. Meanwhile we also show that the millimeter-wave generated in scheme B has better quality and is almost robust to fiber chromatic dispersion. 相似文献
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A millimeter-wave radio-over-fiber system for overcoming fiber dispersion-induced signal cancellation effect 下载免费PDF全文
Chattopadhyay Taraprasad 《光电子快报》2012,8(4):293-296
Millimeter-wave(mm-wave) radio over fiber(ROF) using dispersive single-mode fiber is susceptible to signal cancellation effect at the output of the uni-travelling carrier photodiode at the base station(BS).The fiber dispersion effect produces different phase shifts of the sidebands of the intensity-modulated lightwave which can produce a cancellation of the output signal when mixed with the optical carrier.In this paper,we propose and analyze a novel scheme of mm-wave ROF which uses microwave modulation at the central station(CS) and frequency upconversion before the BSs.This scheme can overcome fiber dispersion-induced signal cancellation effect. 相似文献
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为进一步提高光载无线通信(radio over fiber,ROF)系统中光生毫米波的倍频系数,提出了一种基于4个马赫-曾德尔调制器(Mach-Zehnder modulator,MZM)共同作用的20倍频毫米波信号产生方案。推导了理想情况下倍频方案的产生机理,在仿真实验中,分别分析了非理想因素下调制器直流偏置电压漂移、调制指数、消光比等对系统性能的影响,结果显示,当合理设置各参数的取值范围,其光边带抑制比(optical sideband suppression ratio,OSSR)和射频杂散抑制比(radio frequency spurious sideband suppression ratio,RFSSR)的饱和值高达33.20 dB和27.21 dB;针对基于此倍频方案的ROF系统,对比分析了2.5 Gbit/s数据信号的单双边带调制两种不同传输方式,仿真结果表明,当光纤距离为40 km时,单边带依旧可达无差错传输,降低了传输过程中码间走离效应的影响,增加了系统的传输距离,更适合远距离传输,为微波光子学的发展提供了一种理论依据。 相似文献