高速多带NGI-OOFDM传输系统中的非对称发射机与接收机设计

在高速多带无保护间隔(NGI)光正交频分复用(OOFD M)传输系 统中,采用非对称发射机/接收机结构,对接收信号通过多个通用光相干接收机进行部分探 测,可一次完整 接收整个多带NGI-OOFDM信号。发射端采用单个激光源,通过差分马赫曾德尔外调制器产生 8根等频率 间隔为28GHz的光频梳作为光子载波,经112 Gbit/s PDM-QPSK信号调制,波分复用后形成8路宽带的全 光NGI-OOFDM信号。接收端采用非对称发射机/接收机结构,即采用4个接收带宽为 18GHz的通用光相 干接收机,每个接收机接收2路子载波,可以完整接收整个多带NGI-OOFDM信号。采用本文 结构的高速多 带NGI-OOFDM传输系统,误码率(BER)为10－3时, 光信噪比(OSNR)代价较单载波112Gbit/s PDM-QPSK系 统多约9dB。 经16,0ps/nm光纤色散及偏振扰动,在系统接收端通过电色散补偿 后,约有 0.2dB OSNR代价。最后 对传输13×80km的光纤链路进行了仿真,仿真结果表明,与背靠背 情况相比,在进行电色散补偿后,OSNR代价约1.5dB。     

全光纤波分复用传输系统实验研究

本文报道了一种新颖的波分复用系统－全光纤集成型系统：光发射机由全光纤激光器构成，光传输过程中各节点的上／下载由光纤光栅ADM承担，传输中继则由掺饵光纤放大器完成，在这一全光纤系统上，首次成功地实现了1．2Gbit/s的非归零码、1．2Gbit/s的归零码和2．5GHz、5GHz的模拟信号经100km的传输和下载。     

经过153km标准单模光纤的1550nm 2．488Gb／s传输实验

传输实验证明，采用目前的1550nmDFB激光器，和超过150km标准单模光纤（SMF）的2．488Gb/s光传输系统是不受色散限制的，在消光比为11dB的情况下观察到的色散和消光比代价小于0．7dB。     

750MHz三路输出CATV光接收机的研制

1前言在有线通信技术领域中，无论是公用网还是专用网，其发展总趋势都是以光纤传输取代金属电缆传输。因为光纤有优良的传输特性：一是频带极宽，一般都在GHz量级；二是衰耗很小，比电缆小很多。金属电缆在500MHz时衰耗为40dB／km。而光纤的衰耗低至0．4dB／km（1310n波长）到0．2dB／km（1550nm波长），而且单模光纤的衰耗与工作带宽无关。因此，光缆有线电视技术得到空前大发展。这种技术在传输电视信号时具有许多独特的优良性能。一般有较高的载噪比（C／N），有较低的组合三阶差拍（CTB）和组合二阶失真（CSO）性能，而且直接传…     

采用两个级联外部调制器产生四倍频光载毫米波的光纤无线通信系统

研究了一种采用两个级联外部调制器基于光载波抑制原理产生四倍频毫米波的光纤无线通信(ROF)系统.在中心站利用电混频器产生副载波复用信号,通过第一个外部调制器产生两倍射频(RF)信号的光载毫米波信号,再通过第二个外部调制器产生四倍射频信号的光载毫米波.实验显示采用频率为10 GHz的射频信号源和2.5 Gbit/s的数据基带信号混频通过两个级联外部凋制器后产生毫米波的频率为40 GHz,并且在单模光纤中传输距离达20 km,功率代价小于2 dB.     

采用电光调制器产生光毫米波的全双工通信光纤无线通信系统

实验研究了一种采用单个电光调制器产生光毫米波的方法和相应的全双工无线通信系统。在中心站采用电混频器产生电毫米波,然后再利用电光制器产生双边带信号。利用光交错复用器将中心载波和双频一阶边带信号分离。双频一阶边带用于产生2倍射频信号的光毫米波,而中心光载波用来作为上行链路的光载波。实验显示采用频率为20GHz射频信号产生光毫米波的频率为40GHz,而且将下行链路和上行链路中2.5Gbit/s的数据在单模光纤中传输距离达20km,而功率代价均小于0.5dB。     

广播电视传输系统基础理论知识

干线型光缆传输系统有两种形式，见图6-10所示，当传输距离在30km以下时，采用图6—10（a）所示的光一电一光中继方式1310nm系统。该传输系统由两级光发射机、光缆及光接收机组成。这种系统的发射机采用的是直接调制发射机，其中继对系统性能影响很大，每增加一级中继，载噪比C／N下降4．5dB；C／CTB下降6dB，所以，图6-10（a）所示的光-电～光中继方式1310nm系统，最多只能加入两级中继。当传输距离在（30～150）km时，采用图6—10（b）所示的1550nm系统，可允许将中继放大增加到2～3级，而每增加一级中继，C／N只下降1dB，C／CSO与C／CTB几乎不变。通常，在传输距离允许情况下，如果从经济角度考虑，可以使用1310nm系统。图6—10（C）为干线型光缆网示意图。     

光纤CATV传输系统的结构和应用

光纤CATV传输系统包括光发射机、光接收机、光纤和必要的光通路器件（如光分路器、光纤连接器）等。该系统采用光纤／同轴电缆混合网（HFC）结构，是一种宽带、低成本的实现方式。结合实际开发工作，简要介绍了光发射机、光接收机及相关器件的工作原理。     

三维高集成度微波单片接收机和发射机电路

推《1996IEEEMTT－SInt．MWSymP．Dig．》报道，IchihikoToyoda等人用三维（3D：MMIC工艺开发出了无绳通信系统用的高集成度接收机和发射机，两者的频率分别为9·2－12GHZ和9．5—14GHZ，增益20dB。3DMMIC的基本结构如图1所示。3DMMIC工艺能有效地减小电路面积，显著提高集成度。用这一工艺制作的X波段单片接收机的尺寸仅为2mmX2mm，在9．2－12GHz下，变频增益23士3dB，镜像抑制优于15dB，噪声系数5．5士05dB，增益控制范围在50dB以上，本振功率为0dBm，信号功率一sodBm，中频14o＊HZ；发射机的尺寸仅为1．9mmXI·9mm…     

用于WiMAX的高线性度1W和2W放大器

可以支持750MHz～3．9GHz频带,ALM－31x22功率放大器内置有源偏压电路并且不需射频匹配器件。在典型的5V和400mA偏压条件下,ALM－31122可以在900MHz下带来31．6dBm输出功率（P1dB）、47．6dBm的OIP3和15．6dB增益。ALM－31222则可以在2GHz时提供31．5dBmP1dB、47．9dBm OIP3和14．9dB增益的输出。另外,ALM－31322在3．5GHz下可以提供31dBmP1dB、47．7dBm OIP3以及13．2dB的增益。     

A Novel Low-Cost Fiber In-Line-Type Bidirectional Optical Subassembly

A novel low-cost fiber in-line-type bidirectional optical subassembly using a tilted fiber Bragg grating has been developed for fiber-to-the-home applications. We successfully realized a low-cost subassembly by reducing the number of components and simplifying the packaging process. The extinction ratio of 14.8 dB, receiver minimum sensitivity of -26.5 dBm at a bit-error rate of 10^-12 and frequency response of 2.7 GHz were experimentally obtained. The electrical crosstalk between transmitter and receiver part was less than -86 dB up to 2.5 GHz.     

基于氮化硅微环和载波分离的可重构微波光子带通滤波器

基于Add-Drop型氮化硅微环滤波器,利用光学单边带调制和光载波分离的方法,实现可重构微波光子带通滤波器。滤波器带宽和带外抑制比分别达到726 MHz和37.0dB。并且通过改变光载波波长实现1.64~23.41GHz的滤波器频率调谐;通过调节微环耦合系数实现0.683~2.246GHz的滤波器带宽调谐,在带宽调谐范围内带外抑制比大于26dB。     

A calibrated direct conversion front-end transmitter with resonant matching techniques for mobile WiMAX/WiBro applications

A direct conversion front-end transmitter with the properties of high linearity and high single sideband rejection ratio is described in this paper. The transmitter employs two resonant matching techniques to improve its operating bandwidth. The first resonant circuit design is applied at the inter-stage of the LO input buffer in order to achieve a wideband frequency response which ranges from dc to 6 GHz. The second resonant circuit is applied at the power amplifier (PA) driver output stage to increase the matching bandwidth and meet both the Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Broadband (WiBro) applications simultaneously. In addition, the sideband signal and carrier leakage of this transmitter are further minimized by a proposed calibration circuit design to achieve the error vector magnitude (EVM) specifications. The measured single sideband performance with calibration mechanism demonstrates approximately 15 dB improvement on sideband and carrier suppression. The rejected sideband and carrier signals can be up to 55.19 and 56.31 dBc, respectively. The measured dynamic gain range of the transmitter is 53 dB in 1-dB step with a maximum relative gain error lower than 0.4 dB. The transmitter delivers +0.766 dBm output power with EVM of −34.687 dB for the orthogonal frequency division multiple access (OFDMA) 64QAM-3/4 modulated signals. The measured constellation is minimized to be <1.5% with output power from −2.3 to −36.2 dBm.     

（英）一种基于新型自组装微带-波导过渡的D波段通信发射机模块

展示了一种基于新型自组装微带-波导过渡的D波段（110-170GHz）发射机模块。过渡结构的仿真平均插入损耗为0.6 dB,回波损耗于带内基本优于10 dB。基于该过渡结构以及阻性混频器和倍频器芯片,设计了一种D波段发射机模块。该发射机模块工作于110-153 GHz,峰值输出功率于150 GHz可达-4.6 dBm,3-dB带宽为145.8-159.3 GHz。使用该模块进行了64-QAM高阶无线通信测试,测试传输速率为3 Gb/s,验证了模块封装方案的实用性。     

Optical single-sideband suppressed-carrier modulator for wide-bandsignal processing

We develop and demonstrate a technique for implementing a wide-band optical single-sideband suppressed-carrier modulator. The technique relies on a dual-electrode traveling wave modulator for sideband suppression and a Sagnac fiber-loop interferometer for carrier suppression. The implementation uses all commercially available components and demonstrates >40 dB optical carrier suppression, and as much as 60 dB unwanted signal sideband rejection across a 6-20 GHz microwave frequency range. The modulator is used to demonstrate broad-band spectral shifting- and inversion across the 3-18 GHz frequency range     

Highly integrated 60 GHz transmitter and receiver MMICs in a GaAs pHEMT technology

Highly integrated transmitter and receiver MMICs have been designed in a commercial 0.15 /spl mu/m, 88 GHz f/sub T//183 GHz f/sub MAX/ GaAs pHEMT MMIC process and characterized on both chip and system level. These chips show the highest level of integration yet presented in the 60 GHz band and are true multipurpose front-end designs. The system operates with an LO signal in the range 7-8 GHz. This LO signal is multiplied in an integrated multiply-by-eight (X8) LO chain, resulting in an IF center frequency of 2.5 GHz. Although the chips are inherently multipurpose designs, they are especially suitable for high-speed wireless data transmission due to their very broadband IF characteristics. The single-chip transmitter MMIC consists of a balanced resistive mixer with an integrated ultra-wideband IF balun, a three-stage power amplifier, and the X8 LO chain. The X8 is a multifunction design by itself consisting of a quadrupler, a feedback amplifier, a doubler, and a buffer amplifier. The transmitter chip delivers 3.7/spl plusmn/1.5 dBm over the RF frequency range of 54-61 GHz with a peak output power of 5.2 dBm at 57 GHz. The single-chip receiver MMIC contains a three-stage low-noise amplifier, an image reject mixer with an integrated ultra-wideband IF hybrid and the same X8 as used in the transmitter chip. The receiver chip has 7.1/spl plusmn/1.5 dB gain between 55 and 63 GHz, more than 20 dB of image rejection ratio between 59.5 and 64.5 GHz, 10.5 dB of noise figure, and -11 dBm of input-referred third-order intercept point (IIP3).     

Design techniques for subcarrier multiplexed broadcast opticalnetworks

Design techniques which enable the performance of subcarrier multiplexed FM broadcast optical networks to be optimized at the planning stage are described. At the transmitter node, criteria for maximizing the subscriber carrier-to-noise ratio (CNR) are presented. At the subscriber node, it is shown that under the majority of circumstances, the optimum direct detection receiver consists of a low-noise III-V avalanche photodiode and high-impedance front-end preamplifier. Sensitivities approaching -40 dB (1 mW) for 16.5 dB CNR in 36 MHz subscriber bandwidth are predicted for a 60-channel system. Preliminary experimental tests on an optical-feedback subcarrier receiver showed -34 dB (1 mW) sensitivity at 1.55 μm from 16.5 dB CNR in a 36 MHz bandwidth centered on 1.2 GHz with a 12% modulation index single-channel FM test signal     

非线性光谱展宽载波的湍流信道高速传输特性

采用非线性光谱展宽光源作为高重复频率部分相干光载波光源,开展大气湍流信道中高速信息传输实验研究.通过皮秒光纤激光器泵浦高非线性光纤获得非线性光谱展宽的部分相干光载波光源,重复频率可达10 GHz.采用10 Gbit/s脉冲高速数字调制,通过模拟大气湍流信道传输,相干光载波和部分相干光载波在湍流信道传输前后的信噪比分别从...     

Highly Linear Integrated Optical Transmitter for Subcarrier Multiplexed Systems

A highly linear optical transmitter for radio-over-fiber subcarrier-multiplexed systems is presented. An integrated dual Mach–Zehnder modulator (MZM) is utilized to combine an optical carrier suppressed signal with an optical carrier. The proposed transmitter enables more than 10-dB improvement in the carrier-to-interference ratio compared to a quadrature biased MZM, and similar results to low biased MZM considering similar insertion loss. Negligible radio-frequency power dependence with temperature-induced bias drift is reported, while the low biased MZM is penalized by more than 12 dB for a 15% bias drift. The proposed transmitter reduces the minimum error vector magnitude from 4.2% to 3.5%, when compared to quadrature biased MZM, for a 54-Mb/s orthogonal frequency-division-multiplexed signal.      

Effect of Fog and Clouds on the Image Quality in Millimeter Communications

The effect of fog and clouds in millimeter communication is discussed, and the attenuation caused by fog and clouds is reviewed. Signal-to-noise ratio (SNR) of image is derived using relating models of fog and clouds attenuation. According to the relation of image quality and its signal-to-noise ratio, the system behavior is forecasted theoretically. It is shown that the signal-to-noise ratio of receiver at certain transmitter power is inverse with radio wave frequency, from about 70dB at 10GHz to 48dB for fog and 49dB for clouds. The image quality of received signal at certain transmitter power is inverse with radio wave frequency, from about 7 grade at 10GHz to 5.27 grade for fog and 5.37 grade for clouds. The above calculated results are consistent with experimental results.