A Novel 0.72-6.2GHz Continuously-Tunable Delta Sigma Fractional-N Frequency Synthesizer

This paper presents a wideband Delta Sigma-based fractional-N synthesizer with three integrated quadrature VCOs for multiple-input multiple-output (MIMO) wireless communication applications. It continuously covers a wide range frequency from 0.72GHz to 6.2GHz that is suitable for multiple communication standards. The synthesizer is designed in 0.13-um RE CMOS process. The dual clock full differential multi-modulus divide (MMD) with low power consumption can operate over 9GHz under the worst condition. In the whole range frequency from 0.72GHz to 6.2GHz, the maximal tuning range of the QVCOs reaches 33.09% and their phase noise is -119d8/Hz similar to 124d8/Hz @1MHz. Its current is less than 12mA at a 1.2V voltage supply when it operates at the highest frequency of 6.2GHz.

A 10 Gb/s Directly-Modulated 1.3 mu m InAs/GaAs Quantum-Dot Laser

We demonstrate 10 Gb/s directly-modulated 1.3 mu m InAs quantum-dot (QD) lasers grown on GaAs substrates by molecular beam epitaxy. The active region of the QD lasers consists of five-stacked InAs QD layers. Ridge-waveguide lasers with a ridge width of 4 mu m and a cavity length of 600 mu m are fabricated with standard lithography and wet etching techniques. It is found that the lasers emit at 1293 nm with a very low threshold current of 5 mA at room temperature. Furthermore, clear eye-opening patterns under 10 Gb/s modulation rate at temperatures of up to 50 degrees C are achieved by the QD lasers. The results presented here have important implications for realizing low-cost, low-power-consumption, and high-speed light sources for next-generation communication systems.

An Efficient MMI SOI Splitter with Multimode Input/Output Waveguides

A 1×8 multimode interference power splitter with multimode input/output waveguides in SOI material is designed by the beam propagation method and fabricated by the inductive coupled plasma etching technology for use in fiber optics communication systems.The fabricated device exhibits low loss and good coupling uniformity.The excess loss is lower than 0.8dB,and the uniformity is 0.45dB at the wavelength of 1550nm.Moreover,the polarization dependent loss is lower than 0.7dB at 1550nm.The device size is only 2mm×10mm.

Wide-Band Polarization-Independent Semiconductor Optical Amplifier Gate with Tensile-Strained Quasi-Bulk InGaAs

A semiconductor optical amplifier gate based on tensile-strained quasi-bulk InGaAs is developed. At injection current of 80mA,a 3dB optical bandwidth of more than 85nm is achieved due to dominant band-filling effect.Moreover, the most important is that very low polarization dependence of gain (＜0. 7dB),fiber-to-fiber lossless operation current (70～90mA) and a high extinction ratio (＞50dB) are simultaneously obtained over this wide 3dB optical bandwidth (1520～1609nm) which nearly covers the spectral region of the whole C band (1525～1565nm)and the whole L band (1570～ 1610nm). The gating time is also improved by decreasing carrier lifetime. The wideband polarization-insensitive SOA-gate is promising for use in future dense wavelength division multiplexing (DWDM) communication systems.

Tunable MQW-DBR lasers using selective area growth

The tunable ridge waveguide distributed Bragg reflector (DBR) lasers designed for wavelength-division-multiplex (WDM) communication systems at 1.55 um by using selective area growth (SAG) is reported. The threshold current of the DBR laser is 62mA and the output power is more than 8mW. The isolation resistance between the active region and the Bragg region is 30K Ohm. The total tuning range is 6.5nm and this DBR laser can provide 6 continuous standard WDM channels with 100GHz channel spacing; in the tuning range, the single mode suppression ratio (SMSR) is maintained more than 32dB and the maximum output power variation is less than 3dB.

Simulation and fabrication of thermo-optic variable optical attenuators based on multimode interference coupler

A type of thermo-optic variable optical attenuator based on multimode interference coupler is proposed. The optical field propagation properties of the devices are simulated using finite difference beam propagation method. The propagation loss of the fabricated device is 2-4.2 dB at the wavelength range 1510-1610 nm. The total power consumption is 370 mW and the maximum attenuation is more than 25 dB, which almost can meet the requirements of optical fiber communication systems.

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IEEE

基于USB接口的无线温湿度监测系统

针对环境温湿度检测的需求,设计了一种点对多点的星型无线温湿度监控网络。以无线通信模块nRF401为基础,配合AT89C2051和数字温湿度传感器SHT11构建了从机,以P89C51RD2BN单片机和USB接口芯片PDIUSBD12构建了主机。对系统的硬件原理及温湿度采集方法进行了介绍,对无线通信协议及USB固件设计方法进行了较详细分析。经上位机软件测试,系统运行稳定,具有较好实用性,可应用于多种场合的无线温湿度监测。

第十三章 面向离散工厂自动化的无线通信及网络技术

随着工业无线技术研究的发展,其应用领域已经开始由过程自动化转向离散工厂自动化。与过程自动化相比,工厂自动化对无线通信技术提出了新的需求与挑战。本文阐述了目前无线通信技术在工厂自动化应用中要解决的问题,给出了当前国内外的研究进展。

工业无线网络WIA标准体系与关键技术

工业无线技术是一种本世纪初新兴的、面向设备间信息交互的无线网络技术,适合在恶劣的工业现场环境下使用,具有强抗扰、低功耗、实时通信等技术特征,是对现有无线技术在工业应用方向上的功能扩展和技术创新,并将最终转化为新的无线技术标准。本文介绍我国在工业无线技术方面的研究进展,重点介绍具有自主知识产权的工业无线网络核心技术以及相关国家标准体系的建设情况。

工业无线通信与现场总线集成和互连的研究

近年来快速发展的无线通信技术对工业企业具有极大的吸引力，有助于工业企业降低生产成本、提高生产效率。但在目前阶段，无线通信信道开放和易受干扰、易错的通信特性以及现有的现场总线技术广泛的应用和人力、资金和技术等方面的巨大投入，使得工业无线技术还不可能、也没有必要完全替代现有的有线通信技术。因此，与现有的现场总线等有线通信技术共存和混合使用是当前工业无线通信技术发展和应用的主要方向之一。 工业通信为面向对生产过程监视、控制和管理的自动化系统提供通信服务，具有确定性、硬实时和高可靠性的通信要求。而工业无线通信与有线现场总线的集成和互连会产生一定的问题，影响自动化系统的正常运行。本文针对工业无线通信和有线现场总线集成和互连中存在的互操作和通信性能问题进行了深入的研究，并对WIA-PA和基金会现场总线的集成和互连进行了具体的实现和分析。 本论文首先系统地分析了工业无线通信技术与有线现场总线在工业企业中集成和互连的应用需求，指出了混合现场网段、有线和无线现场网段间、不同层次有线和无线网络的集成和互连是工业无线通信与现场总线混合使用的主要应用方式，并根据工业自动化系统和通信的特点和要求得出互操作和通信性能是集成和互连过程中存在的主要问题。 其次，分析了实现工业无线通信和现场总线集成和互连互操作中的关键问题，即设备、用户应用对象和通信协议各层之间的互操作。提出了以协议转换方式系统实现互操作的理论方法。协议转换可以根据通信协议的异同在不同的通信层次通过协议级、服务级和混合的方式实现，为互操作的实现提供理论和实现基础。 然后，分析了工业无线通信和现场总线集成和互连的通信性能问题，根据自动化系统通信的特点和要求，针对预定周期性通信提出了系统通信调度映射、通信关系和服务转换、资源预留和通信转发和响应方法，对非周期通信提出了优先级及其映射机制、通信关系和服务转换、通信转发和响应以及拥塞控制方法来保证通信的确定、实时和可靠性。 最后，将所提出的方法具体应用于WIA-PA和基金会现场总线的集成和互连，针对通信协议的具体特点，利用通信网关实现了两种协议最高层信息之间的互操作，实现了保证设备间不同通信任务性能的方法，满足了工业自动化系统的要求。

星球探测系统的多机器人组内协作研究

建立了子机器人的控制模型,提出了分散式控制与集中式控制相结合的复合控制体系。采用动态分配ID号和由ID号确定机器人组中领导者的机制,建立了有领导者的机器人组的协作方法。其中,领导者与监控平台之间采用无线通讯,机器人组内采用CAN(control area network)总线传递控制信号。同时采用组内基于状态表匹配的控制方式。两个机器人组合利用以上机制,通过相互协调完成差速转弯的实验验证了该控制方法的可行性。

基于DSP的动态传感器网络实验平台的设计和开发

介绍了一种基于DSP2812的动态传感器网络实验平台的设计与开发.该实验平台的设计由配备各种低成本、低功耗的传感器和无线通信模块的可移动的传感器节点组成.在介绍动态传感器网络实验平台的各个组成部分之后,对系统进行了的基本实验测试,并给出了测试结果.*