摘要：Timing and carrier frequency offset estimation are critical issue for OFDM cooperative communications. In view of the complexity and high accuracy requirement, 1/2 and 1/4 pilot symbol cycle CAZAC sequence structures are defined as the pilot frequency sequence. Estimation within one symbol cycle is carried out through averaging samples of two neighboring symbol cycles, after which the operation is expanded to all the symbol cycles in one band group. Taking multipath effect into account, the concept of phase rotation is proposed for a further step. Adjust the phase difference of estimated symbols by phase rotation, and cross estimation could be done. Meanwhile, timing scheme works within one cycle training sequence. Theoretical and simulation analysis indicate that CRLB does not only relate to estimation symbol length, but also be influenced by phase difference of estimation symbols seriously. In the condition that the length of estimation is fixed, the bigger the phase rotation angle is, the smaller the CRLB is. The complexity of proposed algorithm is less than full cycle average estimation method for almost 50%. Meanwhile, the estimation accuracy is approximate with the full cycle average estimation method as well. Timing scheme with the defined preamble structure is also proposed. Simulation proves its efficiency.

摘要：In this work, power efficient butterfly unit based FFT architecture is presented. The butterfly unit is designed using floating-point fused arithmetic units. The fused arithmetic units include two-term dot product unit and add-subtract unit. In these arithmetic units, operations are performed over complex data values. A modified fused floating-point two-term dot product and an enhanced model for the Radix-4 FFT butterfly unit are proposed. The modified fused two-term dot product is designed using Radix-16 booth multiplier. Radix-16 booth multiplier will reduce the switching activities compared to Radix-8 booth multiplier in existing system and also will reduce the area required. The proposed architecture is implemented efficiently for Radix-4 decimation in time(DIT) FFT butterfly with the two floating-point fused arithmetic units. The proposed enhanced architecture is synthesized, implemented, placed and routed on a FPGA device using Xilinx ISE tool. It is observed that the Radix-4 DIT fused floating-point FFT butterfly requires 50.17% less space and 12.16% reduced power compared to the existing methods and the proposed enhanced model requires 49.82% less space on the FPGA device compared to the proposed design. Also, reduced power consumption is addressed by utilizing the reusability technique, which results in 11.42% of power reduction of the enhanced model compared to the proposed design.

摘要：A sample fiber Bragg grating(SFBG) with Gaussian apodization profile is designed and optimized for the narrowband wavelength filter,and the relevant conclusions provide a guide for the further filter *** the grating length limited,a narrowband(5 GHz) grating filter used in the radio over fiber(ROF) system is fabricated,which has insertion loss of 3.463 dB,sideband suppression of 24.21dB,3 dB bandwidth of 40 pm,and 20 dB bandwidth of 106.3 pm.

摘要：同类，紧张用 photonic 水晶戒指共鸣器(PCRR ) 的调制咸度传感器为从 0% ～ 100% 监视海水的咸度被建议并且设计(到 100 g/L 的 0 g/L ) 在

摘要：A strain-introduced Mach-Zehnder interferometer (MZI) interleaver on lithium niobate (LiNbO3 ) is proposed. The structure of the strain-introduced waveguide is designed in detail, and is produced by depositing a SiO2 film on the annealed proton-exchanged LiNbO3 waveguide. Considering the sensitivities of the edge strain to the deposition temperature and the thickness of the SiO2 film, an optimum design of 50 GHz interleaver on this structure is given through analyzing the effective index changes for E x pq mode by finite difference method (FDM). The length of the bending waveguide in this interleaver is just two thirds of that in the conventional interleaver due to the high refractive index difference.

摘要：Considering that the white LED's spectral response decreases exponentially with the increase of carrier frequency for the on-off-keying non-return-to-zero (OOK-NRZ) visible light communication (VLC) data links, a first-order RC high-pass filter is designed and fabricated as a post-equalizer (PE) to compensate the LED spectral response. Formulation and simulation are both available for illustrating the VLC performance with and without PE. Experiments are performed in detail for the fabricated OOK-NRZ VLC system integrated with PE. The data transmission results show that by using PE, the measured carrier bandwidth is enhanced from 0.8 (0.4-1.2) MHz to 1.7 (0-1.7) MHz, and the bit-error-rate (BER) is less than 10-9. It proves the feasibility of the proposed scheme in OOK-NRZ VLC data links.

摘要：在这份报纸，二维的 photonic 晶体(2DPC ) 基于压力传感器被建议并且设计，并且象敏感那样的察觉到的特征和动态范围从 0 GPa 在压力的范围上被分析到 7 GPa。传感器与坐飞机包围的硅杆的方形的数组基于 2DPC。传感器由二 photonic 水晶伪波导和 L3 缺点组成。L3 缺点被放在二波导之间并且被修改三 Si 杆的半径形成。当增加应用压力水平时，通过模拟，传感器的反响的波长向更高的波长区域线性地被转移，这被注意当增加应用压力水平时。完成的敏感和传感器的动态范围分别地是 2 nm/GPa 和 7 Gpa。

摘要：This paper presents an embedded SRAM design for write buffer applications in flash *** write buffer is implemented with a newly proposed self-adaptive timing control circuit,an area-saving sense-latch circuit and 6 T SRAM cell units.A 2 kb SRAM macro with the area of 135μm×180μm is implemented in and applied to a 128 Mb NOR flash memory with the SMIC 65 nm NOR flash memory *** simulation and chip test results show that the SRAM write buffer is beneficial to high-density flash memory design.

摘要：Good access to traffic information provides enormous potential for automotive powertrain *** propose a logical control approach for the gearshift strategy,aimed at improving the fuel efficiency of *** driver power demand in a specific position usually exhibits stochastic features and can be statistically analyzed in accordance with historical driving data and instant traffic conditions;therefore,it offers opportunities for the design of a gearshift control *** to the discrete characteristics of a gearshift,the control design of the gearshift strategy can be formulated under a logic system *** this end,vehicle dynamics are discretized with several logic states,and then modeled as a logic system with the Markov process *** fuel optimization problem is constructed as a receding-horizon optimal control problem under the logic system framework,and a dynamic programming algorithm with algebraic operations is applied to determine the optimal strategy *** results demonstrate that the proposed control design has better potential for fuel efficiency improvement than the conventional method.

摘要：在高光谱异常检测的基于背景的估计的研究中,背景中存在的异常像元会对背景估计的准确性产生不利影响,通过获得一个不包含异常目标的纯净背景可以有助于提高异常目标检测算法的检测率。因此,本文提出一种基于局部密度的背景纯化方法以去除背景中的异常像元。经典的RX算法(Reed-Xiaoli detector,RXD)在背景统计信息估计时,因初始背景中存在异常像元而产生失真现象。这使RX算法的检测结果具有较高的虚警率。在本文中,将像元的局部密度作为该像元的异常度标签,通过最大类间方差法去除初始背景中潜在的异常像元,最后可以得到更纯净的背景集。利用纯化背景得到更准确的背景统计信息,可以有效降低RX算法的虚警率。首先,通过度量一定半径内的光谱邻域,获得像元的局部密度,半径选取为距离矩阵的平均中位数;然后,基于局部密度设计了两步分割策略:第一步,将原始背景分割为一个包含大部分背景像元的集合及一个混合着背景像元和异常像元的小子集。第二步,利用最大类间方差法处理小子集,获得一个判别阈值,去除局部密度小于该阈值的像元,得到纯净的背景。最后,利用RX检测算法和基于协同表示的检测算法验证所提背景纯化算法的有效性。本文算法对于圣地亚哥海军基地数据和Spec TIR数据,AUC值比LRXD分别提高了0.0246和0.0068,并且相比于其它算法有较高的检测率。实验结果说明,密度背景纯化方法有效抑制了异常点对背景数据的干扰,使背景协方差和均值等参数更准确,降低了虚警率。在计算密度时,需要人为设定半径值。对于两幅高光谱数据,在不同半径选择下DBRAD最大AUC差值为0.0088和0.0012,实验结果表明,人为选择半径值可能会对最后的检测效果造成较大影响。如何自适应选取半径将是下一步研究的重点。