- 标题
- 摘要
- 关键词
- 实验方案
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[IEEE 2018 China International SAR Symposium (CISS) - Shanghai (2018.10.10-2018.10.12)] 2018 China International SAR Symposium (CISS) - Compact Size Multi-Channel True Time Delay Moudle with High Accuracy
摘要： A 9-bit digital true time delay (TDD) and amplification module with high integration is proposed in this paper. The true time delay units, bi-directional amplifiers, serial-to-parallel converter and power pulse modulated circuits are integrated in a multi-chip module (MCM) with monolithic microwave integrated circuit (MMIC) and surface mount technology (SMT). Multi-layer microwave board is used to implement the routing of DC, control and RF signals. Moreover, in order to achieve better flatness of time delay, distributed amplifiers and high isolation cavity structures have been adopted. To calculate the spatial isolation of the cavity structures, electromagnetic simulation with microwave high frequency software has been utilized. For verification, a multi-channel TDD module has been designed, fabricated and measured. According to the measured results, the TDD module achieves the receive gain within 4.5 dB ± 0.8 dB, transmit power within 17dBm ± 1.0 dB, and high time-delay accuracy within ± 0.5 ps for 6.25 ps and ± 20 ps for 1600 ps, simultaneously.
关键词： high accuracy,compact size,multi-channel,true time delay
更新于2025-09-23 15:22:29
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Relationship Between Bistatic Radar Scattering Cross Sections and GPS Reflectometry Delay-Doppler Maps Over Vegetated Land in Support of Soil Moisture Retrieval
摘要： This paper presents the application of a coherent bistatic radar scattering model from vegetated terrains and the extension of the model to circularly polarized incident wave cases for GNSS signals. It will then present an analysis relating the bistatic scattering Radar Cross Sections (RCS) of vegetated land cover to the customary Delay Doppler Maps (DDMs) resulting, e.g., from GNSS reflectometry (GNSS-R) observations. This step is key in being able to use GNSS-R data in soil moisture retrieval algorithms. While some analyses exist for this purpose for scattering from sea surface, such analysis has not been carried out specifically for vegetated land surface. The proposed model and methods are envisioned to be applied to the airborne GNSS Reflectometer Instrument for Bistatic SAR (GRIBSAR) project currently under development, as well as to the CYGNSS mission.
关键词： GRIBSAR,Coherent bistatic radar scattering model,GNSS-R,RCS,Delay Doppler Map
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE Asian Solid-State Circuits Conference (A-SSCC) - Tainan, Taiwan (2018.11.5-2018.11.7)] 2018 IEEE Asian Solid-State Circuits Conference (A-SSCC) - A Sub-Picosecond Hybrid DLL for Large-Scale Phased Array Synchronization
摘要： A large-scale timing synchronization scheme for scalable phased arrays is presented. This approach utilizes a DLL co-designed with a subsequent 2.5GHz PLL. The DLL employs a low noise, fine/coarse delay tuning to reduce the in-band rms jitter to 323fs, an order of magnitude improvement over previous works at similar frequencies. The DLL was fabricated in a 65nm bulk CMOS process and was characterized from 27MHz to 270MHz. It consumes up to 3.3mW from a 1V power supply and has a small footprint of 0.036mm2.
关键词： phase noise,tracking loops,CMOS integrated circuits,radio frequency,phase locked loops,phased-arrays,delay-lines
更新于2025-09-23 15:22:29
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Model Predictive Voltage Control Based on Finite Control Set with Computation Time Delay Compensation for PV Systems
摘要： For the conservativeness and computational delay of the traditional finite control set model predictive control (FCS-MPC), a multi-step model predictive voltage control method based on finite control set (FCS-MMPVC) with delay compensation method is proposed in this paper, and the proposed method is validated on a three-level three-phase voltage source PV inverter. In each control cycle, the twenty-seven voltage vectors for inverters are evaluated on line based on predictive model to obtain the optimal and suboptimal switching state. The selected switching state is optimal in two control cycle with the proposed method. Considering that the time spent in the actual sampling and calculation process cannot be ignored, the delay compensation is added in FCS-MMPVC algorithm. The simulation and experimental results show that the proposed method has good stability and reliability. Compared with the traditional FCS-MPC algorithm, the proposed method can reduce the difference significantly between the output voltage and the reference under the unbalanced and non-linear load, and the output voltage quality of the inverter is improved.
关键词： Delay compensation,Multi-step model predictive voltage control,PV inverter,Finite control set
更新于2025-09-23 15:21:21
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Laser Pouch Motors: Selective and Wireless Activation of Soft Actuators by Laser-powered Liquid-to-gas Phase Change
摘要： A joint optimization problem of link-layer energy efficiency (EE) and effective capacity (EC) in a Nakagami-m fading channel under a delay-outage probability constraint and an average transmit power constraint is considered and investigated in this paper. First, a normalized multi-objective optimization problem (MOP) is formulated and transformed into a single-objective optimization problem (SOP), by applying the weighted sum method. The formulated SOP is then proved to be continuously differentiable and strictly quasiconvex in the optimum average input power, which turns out to be a cup shape curve. Furthermore, the weighted quasiconvex tradeoff problem is solved by first using Charnes–Cooper transformation and then applying Karush–Kuhn–Tucker (KKT) conditions. The proposed optimal power allocation, which includes the optimal strategy for the link-layer EE-maximization problem and the EC-maximization problem as extreme cases, is proved to be sufficient for the Pareto optimal set of the original EE–EC MOP. Moreover, we prove that the optimum average power level monotonically decreases with the importance weight, but strictly increases with the normalization factor, the circuit power and the power amplifier efficiency. Simulation results confirm the analytical derivations and further show the effects of fading severeness and transmission power limit on the tradeoff performance.
关键词： energy efficiency,weighted sum method,delay-outage probability constraint,Quality-of-service,effective capacity,multi-objective optimization problem
更新于2025-09-23 15:21:01
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High-Speed Neuromorphic Reservoir Computing Based on a Semiconductor Nanolaser with Optical Feedback Under Electrical Modulation
摘要： A high-speed neuromorphic reservoir computing system based on a semiconductor nanolaser with optical feedback (SNL-based RC) under electrical modulation is proposed for the first time and demonstrated numerically. A Santa-Fe chaotic time series prediction task is employed to quantify the prediction performance of the SNL-based RC system. The effects of the Purcell cavity-enhanced spontaneous emission factor F and the spontaneous emission coupling factor β on the proposed RC system are analyzed extensively. It is found that, in general, increased F and β extend the range of good prediction performance of the SNL-based RC system. Moreover, the influences of bias current and feedback phase are also considered. Due to the ultra-short photon lifetime in SNL, the information processing rate of the SNL-based RC system reaches 10Gpbs. The proposed high-speed SNL-based RC system in this paper provides theoretical guidelines for the design of RC-based integrated neuromorphic photonic systems.
关键词： spontaneous emission coupling factor,Purcell factor,reservoir computing,Semiconductor nanolaser,delay systems
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 5th International Conference for Convergence in Technology (I2CT) - Bombay, India (2019.3.29-2019.3.31)] 2019 IEEE 5th International Conference for Convergence in Technology (I2CT) - Multiplexer based Voltage Controlled Delay Buffer Element
摘要： This paper presents a voltage controlled delay buffer using a 2:1 multiplexer, designed in 0.35 μm CMOS process. The multiplexer is realized with transmission gate, which results in achievement of high speed, low power and full swing output characteristics of delay buffer. The least attained post layout rising edge delay is 120 ps that is comparable with standard cell inverter. The delay regulation range achieved over control voltage of 0 V to 3.3 V is from 120ps to 560ps. The performance of delay buffer for single edge delay control across PVT variations is successfully verified by design of modified delay lock loop.
关键词： Process Voltage and Temperature (PVT),Current Starved Inverter,Time-to-Digital Converter (TDC),Delay Lock Loop (DLL)
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - UV-stable surface passivation for crystalline silicon cells in solar modules with UV light transmitting encapsulation materials
摘要： This letter is concerned with experimental results of aircraft positioning by using terrestrial digital broadcasting signal delay. Passive bistatic radar (PBR) is expected to be a conventional primary surveillance radar alternative, and it can also achieve expanding coverage area of the conventional radar. The PBR sensors allow the detection and tracking of noncooperative targets illuminated by transmitters of opportunity such as communication systems [digital terrestrial television broadcasting (DTTB), AM/FM, 3G/LTE base stations, etc.] or conventional radar system. Especially, the DTTB signals are the most expected radio waves. In this letter, we show experimental results of aircraft positioning by using the signal delay profile of DTTB whose type is Integrated Services Digital Broadcasting–Terrestrial (ISDB-T) used in Japan. It will be shown that the ISDB-T signal delays are useful surveillance systems.
关键词： digital terrestrial television broadcasting,multistatic primary surveillance radar (MSPSR),Aircraft surveillance,signal delay,passive bistatic radar,Integrated Services Digital Broadcasting–Terrestrial
更新于2025-09-23 15:21:01
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[IEEE 2019 XXIX International Scientific Symposium "Metrology and Metrology Assurance" (MMA) - Sozopol, Bulgaria (2019.9.6-2019.9.9)] 2019 XXIX International Scientific Symposium "Metrology and Metrology Assurance" (MMA) - The metod of reducing measurement error of the propagation delays in optical elements and optical fibers
摘要： The paper presents a method of reducing the measurement error propagation delays of signals in optical elements and optical fibers, based on the approximation of the recorded form of optical pulses and determining the time intervals between pulses, using the values of the parameters of the approximating functions. The scheme of the installation implementing the proposed method is presented, as well as the results of experimental approbation of the method.
关键词： optical element,optical fiber,signal propagation delay,approximation
更新于2025-09-23 15:21:01
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Study of Laser-Generated Longitudinal Waves Interacting with an Internal Spherical Cavity by Use of a Transmission Time Delay Method
摘要： In order to improve the detection sensitivity and stability of scanning laser ultrasound techniques, we propose a transmission time delay method, based on the time delay of transmitted longitudinal waves, for the evaluation of the size and position of an internal cavity. By studying the interacting process between the longitudinal wave and the internal cavity through theory and finite element method, the relationships among the time delay, cavity radius, and the detection distance were determined. The monotonicity of the relationship indicates that the time delay can be used to inverse the radius and the depth position of the internal cavity. The laser ultrasound experiments were performed on three aluminum samples with different internal cavities through the concentric transmission method. The C-scan results show that compared with using amplitude attenuation to detect the cavity, the time delay of transmitted waves can detect the internal cavities more stably and accurately. The experimental data are close to the theoretical and simulation results, and the inversion of cavity depth was achieved based on the measured parameters (the time delay, cavity radius, frequency, velocity). The results demonstrate that the transmission time delay method has a great application potential in the localization and quantification of the internal defects.
关键词： Laser ultrasonic,Time delay,Longitudinal wave,Internal cavity,Creeping wave
更新于2025-09-23 15:21:01