MEMS-tunable vertical-cavity SOAs

We present the signal gain, wavelength tuning characteristics, saturation properties, and noise figure (NF) of MEMS-based widely tunable vertical-cavity semiconductor optical amplifiers (VCSOAs) for various optical cavity designs, and we compare the theoretical results to data generated from a number of experimental devices. Using general Fabry-Pe/spl acute/rot relationships, it is possible to model both the wavelength tuning characteristics and the peak signal gain of tunable vertical-cavity amplifiers, while a rate-equation analysis is used to describe the saturation output power and NF as a function of the VCSOA resonant wavelength. Additionally, the basic design principles for an integrated electrostatic actuator are outlined. It is found that MEMS-tunable VCSOAs follow many of the same design trends as fixed-wavelength devices. However, with tunable devices, the effects of varying mirror reflectance and varying single-pass gain associated with the MEMS-based tuning mechanism lead to changing amplifier properties over the wavelength span of the device.     

Cross-talk attack monitoring and localization in all-optical networks

The effects of an attack connection can propagate quickly to different parts of an all-optical transparent network. Such attacks affect the normal traffic and can either cause service degradation or outright service denial. Quick detection and localization of an attack source can avoid losing large amounts of data in an all-optical network. Attack monitors can collect the information from connections and nodes for diagnostic purpose. However, to detect attack sources, it is not necessary to put monitors at all nodes. Since those connections affected by the attack connection would provide valuable information for diagnosis, we show that by placing a relatively small number of monitors on a selected set of nodes in a network is sufficient to achieve the required level of performance. However, the actual monitor placement, routing, and attack diagnosis are challenging problems that need research attention. In this paper, we first develop our models of crosstalk attack and monitor node. With these models, we prove the necessary and sufficient condition for one-crosstalk-attack diagnosable networks. Next, we develop a scalable diagnosis method which can localize the attack connection efficiently with sparse monitor nodes in the network.     

基于神经网络的电机智能检测系统

利用神经网络技术建立电机的检测模型，由计算机构筑电机智能检测系统，与电机控制和执行机构相结合，对电动机进行控制，利用各种新型的传感技术，实现电动机各种参数的数据采集与分析处理，从而对电动机的性能进行判断。     

Ka-band analog front-end for software-defined direct conversion receiver

A six-port Ka-band front-end architecture based on direct conversion for a software-defined radio application is proposed in this paper. The direct conversion is accomplished using six-port technology. In order to demodulate various phase-shift-keying/quadrature-amplitude-modulation (PSK/QAM) modulated signals at a high bit rate, a new analog baseband circuit was specially designed according to the I/Q equations presented in the theoretical part. An experimental prototype has been fabricated and measured. Simulation and measurement results for binary PSK, quaternary PSK (QPSK), 8 PSK, 16 PSK, and 16 QAM modulated signals at a bit rate up to 40 Mb/s are presented to validate the proposed approach. A software-defined radio can be designed using the new front-end and only two analog-to-digital converters (ADCs) because the I/Q output signals are generated by analog means. Previous six-port receivers make use of four ADCs to read the six-port dc levels and require digital computations to generate the I/Q output signals. With the proposed approach, the load of the signal processor will therefore be reduced and the modulation speed can be significantly increased using the same digital signal processor.     

LTE小区间干扰抑制技术介绍及比较

主要介绍了LTE目前采用的干扰抑制的方法,说明了这些干扰抑制方法对抑制小区间干扰,提高系统性能的作用,并比较了不同方法的优劣。     

Dual-polarised single-layer slotted patch antenna

A compact design of the single-layer slotted microstrip patch antenna is presented, which has two highly decoupled orthogonal input ports and is capable of generating dual-polarised radiation. The proposed antenna displays a desired characteristic for reducing polarisation loss between the transmitting and receiving antenna units at arbitrary angles. The measured results show that the proposed antenna with resonance frequency at 5.93 GHz has a bandwidth of about 300 MHz, an average gain of greater than 8 dBi, and an input isolation of exceeding 20 dB for the entire impedance bandwidths of the two polarisations.     

激光扫描条纹管成像水下探测技术进展

论述了激光扫描条纹管成像的基本原理、国内外发展和应用情况以及国内初步试验结果。可利用以条纹管成像为基础的水下激光扫描成像探测技术,增加水下光学探测距离,提高水下探测速度和效率;在水下无人航行体(UUV)、舰载、机载等装备上实现快速探测和识别水下目标。     

AUV与平台对接过程水动力干扰数值计算

AUV在与平台对接过程中会受到平台的非定常干扰作用,与AUV在宽阔流域中的受力特性有很大差异。基于RNGκ-ε湍流模型,采用有限体积法和非结构动网格技术,在不同雷诺数下和不同攻角下数值模拟了AUV对接过程中的非定场流场。仿真结果表明干扰力随AUV与平台的间距减小而增大,随着运动速度或者雷诺数的增大而减小,随攻角的增大而增大。