掩埋隧道结VCSEL芯片小信号等效电路模型

提出了适用于一种1.55μm掩埋隧道结垂直腔面发射激光器(VCSEL)芯片的小信号等效电路模型.等效电路的提出是基于半导体激光器速率方程以及VCSEL芯片结构,电路中各元件都有严格的物理意义.根据实验测得芯片的反射系数及传输参数,通过小信号等效电路仿真模拟,得到电路各元件参数值.不同偏置电流下,模拟结果与实验结果吻合都非常好,证明了该等效电路的有效性.     

Edge Effect Elimination in Single-Mixture Blind Source Separation

Blind source separation (BSS) of single-channel mixed recording is a challenging task that has applications in the fields of speech, audio and bio-signal processing. Ensemble empirical mode decomposition (EEMD)-based methods are commonly used for blind separation of single input multiple outputs. However, all of these EEMD-based methods appear in the edge effect problem when cubic spline interpolation is used to fit the upper and lower envelopes of the given signals. It is therefore imperative to have good methods to explore a more suitable design choice, which can avoid the problems mentioned above as much as possible. In this paper we present a novel single-mixture blind source separation method based on edge effect elimination of EEMD, principal component analysis (PCA) and independent component analysis (ICA). EEMD represents any time-domain signal as the sum of a finite set of oscillatory components called intrinsic mode functions (IMFs). In extreme point symmetry extension (EPSE), optimum values of endpoints are obtained by minimizing the deviation evaluation function of signal and signal envelope. Edge effect is turned away from signal by abandoning both ends’ extension parts of IMFs. PCA is applied to reduce dimensions of IMFs. ICA finds the independent components by maximizing the statistical independence of the dimensionality reduction of IMFs. The separated performance of edge EPSE-EEMD-PCA-ICA algorithm is compared with EEMD-ICA and EEMD-PCA-ICA algorithms through simulations, and experimental results show that the former algorithm outperforms the two latter algorithms with higher correlation coefficient and lower relative root mean square error (RRMSE).     

Synthesis of Graphene Sheets and Characterization of Poly(3-hexylthiophene):Graphene Blends

Graphite is a bulk-layered material that can be separated into sheets which exhibit folds and pleat-like structures. Graphene sheets are easily obtained via an exfoliation process using graphite in organic solvent. Spin-coated graphene:poly(3-hexylthiophene) (P3HT) blend films are characterized by absorption and photoluminescence spectroscopy measurements. Doping of 2.5% graphene into P3HT induces better light absorption and photoluminescence quenching in the blend film. This finding indicates that graphene is a potential alternative material in various applications such as an acceptor material in organic solar cells.     

IP城域网业务接入控制层业务备份技术探讨

越来越多的电信业务通过IP网络承载,对IP城域网的可靠性提出了极高的要求.业务接入控制层在IP城域网中是多业务融合承载的关键设备,在网络中承担着承上启下的功能.根据运营实践和业务测试,分析了业务接入控制层设备业务备份目前的技术现状,提出了在新型承载网络架构中构建高可靠性业务接入控制层的方法和建议.     

A high PSRR CMOS voltage reference with 1.2 V operation

A high power supply rejection ratio (PSRR) CMOS band-gap reference (BGR) with 1.2 V operation is proposed in this paper. The reference features include an error amplifier with a trimming circuit and a trimming resistor array on the chip. Local positive feedback is used in the error amplifier to obtain high gain. By trimming the resistor array, the PSRR of the error amplifier is trimmed around one to obtain a high PSRR. The trimming resistor array is controlled externally. The post simulation results indicate that the PSRR is up to ?130 dB@DC and ?89 dB@10 kHz. The experimental results show that, under a supply voltage of 1.2 V the measured PSRR is ?103 dB@dc and ?74 dB@10 kHz.     

基于LU分解的稀疏目标定位算法

针对基于orth的稀疏目标定位算法中orth预处理会影响原信号的稀疏性的问题,该文提出一种基于LU分解的稀疏目标定位算法。该算法通过网格化感知区域把目标定位问题转化为压缩感知问题,并利用LU分解法对观测字典进行分解得到新的观测字典。该观测字典有效地满足了约束等距性条件,同时对观测值的预处理过程不影响原信号的稀疏性,从而有效地保证了算法的重建性能,提升了算法的定位精度。实验结果表明,基于LU分解的稀疏目标定位算法的性能远优于基于orth的稀疏目标定位算法,目标的定位精度得到了较大地提升。     

一种新的HomePNA网络动态带宽分配算法

基于同轴的家庭电话线网络联盟(HomePNA)3.0网络是一个上下行共享同一频段,使用同步媒体接入控制(SMAC)或异步媒体接入控制(AMAC)方式工作的系统.为保障视频、语音和数据等多业务的服务质量(QoS)特性,文章提出了一种新的动态带宽分配算法,即高优先级业务基于流的带宽预留和低优先级业务基于流量统计的上行带宽分配.给出了模型和仿真结果,证明了这种算法的正确性.     

MFSK水声远程通信技术及试验研究

海洋水声信道是多途、时变和频散的信道。论文针对浅海远程80～100km,设计出基于MFSK高数据率水声远程信息传输最佳系统。本系统经湖试验证表明:该技术在远程通信恶劣条件下具有较强抗多径干扰和信道衰落能力,对同步精度要求低,可实现80～100km,40bit/s,10-4量级通信精度的信息可靠传输,性能稳健,易于工程实现。     

基于混合PN／肖特基结构的新一代600V SiC肖特基二极管

第二代碳化硅(SiC)肖特基二极管——thinQ!2G是由一个肖特基结构和一个与它平行的独特的低电阻PN结组成,因此具备更加强大的浪涌电流处理能力,同时又继承了第一代碳化硅肖特基二极管所实现的良好的动态性能。     

基于DSP和FPGA的电视观瞄系统设计

电视观瞄系统以FPGA为处理核心，实现红外数字视频信号的实时图像处理，DSP实现了部分的图像处理算法和FPGA的控制逻辑，并响应中断，实现数据通信和存储。[编者按]