Author Affiliations
Abstract
1 Beijing University of Posts and Telecommunications, Beijing 100876, China
2 Nanjing University of Information Science & Technology, Nanjing 210044, China
This Letter proposes a high-security modulation scheme for optical transmission systems. By using multi-constellation shaping and asymmetric encryption, the information security can be enhanced and quantum computer cracking can be effectively resisted. Three-dimensional (3D) carrier-less amplitude phase modulation is utilized to superposition and transmit 3D signals. Experimental verification is conducted using a seven-core weakly coupled fiber platform. The results demonstrate that the proposed scheme can effectively protect the system from any illegal attacker.
multi-core transmission asymmetric encryption multi-constellation shaping Chinese Optics Letters
2024, 22(4): 040602
Author Affiliations
Abstract
1 Nanjing University of Information Science & Technology, Nanjing 210044, China
2 Key Laboratory for Information Science of Electromagnetic Waves (MoE), Fudan University, Shanghai 200433, China
We propose a neural network equalization delta-sigma modulation (DSM) technique. After performing DSM on the multi-order quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM) signal at the transmitting end, neural network equalizer technology is used in the digital signal processing at receiving end. Applying this technology to a 4.6 km W-band millimeter wave system, it is possible to achieve a 1 Gbaud 8192-QAM OFDM signal transmission. The data rate reached 23.4 Gbit/s with the bit error rate at 3.8 × 10-2, lower than soft-decision forward-error correction threshold (4 × 10-2).
multi-order quadrature amplitude modulation W-band delta-sigma modulation neural network equalization nonlinear compensation Chinese Optics Letters
2024, 22(4): 040601
Author Affiliations
Abstract
1 School of Information Science and Technology, Fudan University, Shanghai 200433, China
2 Changfei Optical Fiber and Cable Joint Stock Limited Company, Wuhan 430073, China
3 Nanjing University of Information Science & Technology, Nanjing 210000, China
We experimentally transmit eight wavelength-division-multiplexing (WDM) channels, 16 quadratic-amplitude-modulation (QAM) signals at 32-GBaud, over 1000 km few mode fiber (FMF). In this experiment, we use WDM, mode division multiplexing, and polarization multiplexing for signal transmission. Through the multiple-input–multiple-output (MIMO) equalization algorithms, we achieve the total line transmission rate of 4.096 Tbit/s. The results prove that the bit error rates (BERs) for the 16QAM signals after 1000 km FMF transmission are below the soft-decision forward-error-correction (SD-FEC) threshold of , and the net rate reaches 3.413 Tbit/s. Our proposed system provides a reference for the future development of high-capacity communication.
optical fiber communication mode division multiplexing few-mode fiber multiple-input–multiple-output high-capacity transmission long-distance transmission Chinese Optics Letters
2024, 22(1): 010602
群组行为识别是对个体的共同行为进行识别。群组行为与群组状态密不可分,也与群组内个体时空特征息息相关,时空信息既能描述空间语义信息,更能反映行为的动态变化情况。针对有效精细的时空特征提取问题,本文提出了一种基于注意力机制和深度时空信息的群组行为识别方法。首先将 ShuffleAttention引入双流特征提取网络中,有效提取个体外观和运动信息。其次使用改进 Non-Local网络提取深度时序信息。最后将个体特征送到图卷积网络中进行空间交互信息建模,得到群组行为识别结果。在 CAD和 CAED数据集上的准确率达到了 93.6%和 97.8%,在 CAD数据集上与凝聚群组搜索算法(CCS)和成员关系图 (ARG)方法相比,准确率提高了 1.2%和 2.6%,这表明本文方法能有效提取深度时空特征,提升群组行为识别准确率。
群组行为识别 注意力机制 时空特征 交互关系 非局部网络 group activity recognition attention mechanism saptio-temporal information interactive relationships non-local network 太赫兹科学与电子信息学报
2023, 21(5): 661
河南科技大学 电气工程学院, 河南 洛阳 471023
提出了一种基于TSMC 40 nm/0.9 V CMOS工艺设计的适用于音频范围的低功耗高性能栅压自举采样开关电路。通过PMOS晶体管的衬底和漏极相连接代替了时钟放大模块,极大降低了电路整体的功耗。在输入端增加了一个NMOS晶体管,随着开关时钟的开启/关闭,通过抑制核心采样晶体管的体效应,可以有效提高开关线性度。鉴于音频信号的范围,选用频率为19.53 kHz、幅值为0.3 V的正弦波信号进行10 MHz采样频率的高速采样仿真,与传统结构相比,有效位数(ENOB)、信噪比(SNR)、无杂散动态范围(SFDR)和总谐波失真(THD)四项性能指标分别提升了5.5%、3.7%、13.8%和5.4%,并且功耗降低了36.8%。
低功耗 高性能 栅压自举采样开关 low-power high-performance bootstrap sampling switch
1 桂林电子科技大学广西精密导航技术与应用重点实验室, 广西 桂林 541000
2 桂林电子科技大学信息与通信学院, 广西 桂林 541000
3 卫星导航定位与位置服务国家地方联合工程研究中心, 广西 桂林 541000
4 南宁桂电电子科技研究院有限公司, 南宁 530000
针对无人机图像匹配时间较长的问题, 提出了一种基于SIFT改进的无人机图像匹配算法。引入了FAST算法检测角点, 它能快速通过比较中心像素点和一定领域内像元的灰度值以判断是否为角点, 从而提高算法的速度。同时, 为了弥补FAST算法在高斯差分金字塔上搜索的不足, 使用了基于Ostu和GA的图像分割算法对图像进行分割, 对分割图像构建高斯金字塔, 在高斯金字塔上进行特征点搜索。实验结果表明, 与传统的SIFT算法相比, 改进算法提高了无人机图像匹配的速率和正确率。
无人机 图像匹配 图像分割 高斯金字塔 特征点搜索 UAV image matching image segmentation Gaussian pyramid feature points search
1 国网宁夏电力有限公司超高压公司,宁夏 银川 750001
2 浙江工业大学机械工程学院,浙江 杭州 310023
采用激光辅助低压冷喷涂技术在Cu基体上制备表面金属化CNTs(Ni-Cu-CNTs)/Cu复合涂层,研究了复合涂层的微观特性以及耐磨损性能。研究结果表明,在激光辐照的作用下,Ni-Cu-CNTs增强相和Cu黏结相由于受热软化均发生了明显的塑性变形,Ni-Cu-CNTs颗粒嵌入到塑性变形的Cu颗粒中形成连续致密且结合良好的复合涂层,复合涂层的厚度可达2609 μm,CNTs弥散均匀分布在复合涂层中且保持其结构的完整性。添加Ni-Cu-CNTs的复合涂层表现出优异的耐磨损性能,平均摩擦系数可降低至0.385,体积磨损速率降至1.49×10-4 mm3/(N·m)。复合涂层中的Ni-Cu-CNTs增强相一方面通过承受磨球对涂层表面的载荷力,减少了涂层磨损,另一方面随着磨损过程的进行,Ni-Cu-CNTs从涂层中脱离到涂层表面形成润滑层,降低了涂层的摩擦系数,从而提高复合涂层的耐磨损性能。
激光技术 低压冷喷涂 CNTs/Cu复合涂层 微观特性 耐磨损性能 激光与光电子学进展
2023, 60(21): 2114008