- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Leakage Mitigation in Heterodyne FMCW Radar for Small Drone Detection With Stationary Point Concentration Technique
摘要： To prevent potential hazards posed by fast-evolving drones, it is of importance to develop a radar system for drone detection. Frequency modulated continuous wave (FMCW) radars are widely used for that purpose. Heterodyne architectures are preferred for them to mitigate dc offset errors. Having said that, FMCW radars suffer from permanent leakage from the transmitter into the receiver. The leakage phase noise raises the total noise floor and limits the radar sensitivity. Here, we propose a stationary point concentration (SPC) technique in order to overcome the challenges. The SPC technique concentrates the leakage phase noise on a stationary point to alleviate the impact of the noise. The technique can be realized using digital signal processing without additional hardware. The results show that the proposed technique significantly lowers the noise floor.
关键词： heterodyne,down-conversion,leakage,digital signal processing (DSP),frequency modulated continuous wave (FMCW) radar,stationary point concentration (SPC) technique,stationary point,phase noise,noise floor
更新于2025-09-23 15:22:29
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Shaping pulses of radiation detectors into a true Gaussian form
摘要： A digital shaper for conversion of detector pulses with a short leading edge and a long exponential tail into a true Gaussian form is proposed and analysed in this paper. The width of Gaussian pulses can be several times smaller than the rise time of the input pulses, i.e. considerably shorter than the undistorted output pulses provided by standard shapers. The algorithm of the true Gaussian shaper is presented in the paper. The output pulses and noises of the true Gaussian shapers are compared with those of standard shapers for different widths of shaped pulses. The analyses has shown that the true Gaussian shaping can be advantageous for detection of strongly overlapped pulses which appear at high particle fluxes in the detector input.
关键词： Digital signal processing (DSP),Electronic detector readout concepts (solid-state),Solid state detectors,Nuclear instruments and methods for hot plasma diagnostics
更新于2025-09-19 17:15:36
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[IEEE 2018 International Conference Laser Optics (ICLO) - St. Petersburg (2018.6.4-2018.6.8)] 2018 International Conference Laser Optics (ICLO) - Spectroscopic and laser properties of Tm <sup>3+</sup> ions optical centers in CaF2-YF3:Tm <sup>3+</sup> solid solutions
摘要： In this paper, we review recent progress on space division multiplexed (SDM) transmission and our proposal of dense SDM (DSDM) with more than 30 spatial channels toward capacities beyond petabit/s. Furthermore, we discuss the requirements for realizing long-haul DSDM transport systems using multicore and/or multimode fiber, including power and space efficient amplification schemes, the use of fibers with large effective areas and transmission lines with low intercore crosstalk, low differential mode delay (DMD), and low mode dependent loss (MDL). Graded index heterogeneous 12-core × 3-mode fiber with low crosstalk, low DMD, and low MDL, parallel multiple-input and multiple-output signal processing, low mode dependent gain Erbium-doped fiber amplifiers, and MDL equalization technologies are significant as regards extending the reach of multicore and multimode transmission. We review our long-distance transmission experiment on polarization-division multiplexed 16-quadrature amplitude modulation signaling over 12-core × 3-mode fiber.
关键词： optical communication systems,optical fibers,optical fiber communication,spectral efficiency,space division multiplexing,Digital signal processing (DSP)
更新于2025-09-19 17:13:59
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Machine Learning for 100Gb/s/λ Passive Optical Network
摘要： To respond the growing bandwidth demand by emerging applications such as fixed-mobile convergence for 5G and beyond 5G, 100Gb/s/λ access network becomes the next research focus of passive optical network (PON) roadmap. Intensity modulation and direct detection (IMDD) technology is still considered as a promising candidate for 100Gb/s/λ PON attributed to its low cost, low power consumption and small footprint. In this paper, we achieve 100Gb/s/λ IMDD PON by using 20G-class optical and electrical devices due to its commercial linear and nonlinear availability. To mitigate the system distortions, neural network (NN) based equalizer is used and the performance is compared with feedforward equalizer (FFE) and Volterra nonlinear equalizer (VNE). We introduce the rules to train and test the data when using NN-based equalizer to guarantee a fair comparison with FFE and VNE. Random data has to be used for training, but for test, both random data and psudo-random bit sequence (PRBS) are applicable. We found NN-based equalizer has the same performance with FFE and VNE in the case of linear distortion only, but outperforms them in strong nonlinearity case. In the experiment, to improve the loss budget, we increase the launch power to 18 dBm, achieving a 30-dB loss budget for 33Gbaud/s PAM8 signal at the system frequency response of 16.2 GHz, attributed to the strong nonlinear equalization capability of NN.
关键词： neural network (NN),machine learning,intensity modulation and direct detection (IMDD),digital signal processing (DSP),Passive optical network (PON)
更新于2025-09-04 15:30:14