共查询到20条相似文献,搜索用时 15 毫秒
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为了优化设计基于光学差分参量放大的布里渊光时域分析抽运的脉冲编码形式以及斯托克斯光与反斯托克斯光脉宽差,采用微扰法和小信号近似法,获得了探测光与斯托克斯光脉冲、反斯托克斯光脉冲在较小作用区域内的脉冲响应,对其性能进行了理论分析与数值验证。结果表明,相位斯托克斯光脉冲可有效压缩布里渊增益谱宽,提高布里渊信号信噪比;当斯托克斯光与反斯托克斯光传感脉冲脉宽差为8ns时,探测光布里渊增益最大。这一结果对进一步分析基于光学差分参量放大的布里渊光时域分析系统性能以及开展相关实验研究是有帮助的。 相似文献
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A physically based, scalable MOS varactor model and extraction methodology for RF applications 总被引:1,自引:0,他引:1
Victory J. Zhixin Yan Gildenblat G. McAndrew C. Jie Zheng 《Electron Devices, IEEE Transactions on》2005,52(7):1343-1353
A physically based scalable model for MOS varactors, including analytical surface potential based charge modeling and physical geometry and process parameter based parasitic modeling, is proposed. Key device performances of capacitance and quality factor Q are validated over a wide voltage, frequency, and geometrical space. The model, implemented in Verilog-A for simulator portability, provides for robust and accurate RF simulation of MOS varactors. 相似文献
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The single-sideband phase noise of varactor tunable GaAs MESFET oscillators is investigated. Two oscillator circuits with different microstrip resonator circuits were designed and fabricated. Using a resonator consisting of coupled microstrip lines instead of a single microstrip line, which is a planar monolithically integrable structure, phase noise is reduced significantly because the quality factor is higher for the coupled resonator. The phase noise is calculated using a nonlinear time domain method, which solves the Langevin equations, describing the deterministic and stochastic behavior of an oscillator by perturbation methods. Calculated and measured phase noise agree within the accuracy of measurements. The very low phase noise of 95 dBc/Hz at 100 kHz offset frequency is achieved 相似文献
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Gopalakrishnan K. Woo R. Jungemann C. Griffin P.B. Plummer J.D. 《Electron Devices, IEEE Transactions on》2005,52(1):77-84
Part I of this paper dealt with the fundamental understanding of device physics and circuit design in a novel transistor, based on the field-effect control of impact-ionization (I-MOS). This paper focuses on experimental results obtained on various silicon-based prototypes of the I-MOS. The fabricated p-channel I-MOS devices showed extremely abrupt transitions from the OFF state to the ON state with a subthreshold slope of less than 10 mV/dec at 300 K. These first experimental prototypes of the I-MOS also showed significant hot carrier effects resulting in threshold voltage shifts and degradation of subthreshold slope with repeated measurements. Hot carrier damage was seen to be much worse in nMOS devices than in pMOS devices. Monte Carlo simulations revealed that the hot carrier damage was caused by holes (electrons) underneath the gate in pMOS (nMOS) devices and, thus, consequently explained the difference in hot carrier effects in p-channel versus n-channel I-MOS transistors. Recessed channel devices were also explored to understand the effects of surfaces on the enhancement in the breakdown voltage in I-MOS devices. In order to reduce the breakdown voltage needed for device operation, simple p-i-n devices were fabricated in germanium. These devices showed much lower values of breakdown voltage and excellent matches to MEDICI simulations. 相似文献
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《Solid-State Circuits, IEEE Journal of》1975,10(5):322-331
An experimental and theoretical study of double-diffused MOS transistors (DMOST's) has been made. A simple, analytic two-transistor model gives insight into DMOS device physics as well as predicting DMOST characteristics. Both the model and experimental results show that three distinct regions of operation exist: short-channel control, long-channel control, and carrier velocity saturation control. Quantitative criteria are established for judging the region of operation as a function of device parameters and terminal voltages. A DMOST may be optimized to have the same d.c. characteristics as its short-channel component transistor over most of its operating range. A two-transistor model suitable for Computer-Aided Circuit Design (CAD) is also presented. 相似文献
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The metal oxide semiconductor (MOS)-controlled diode (MCD) is a new class of power semiconductor diode that can achieve ideal diode performance. In this paper, experimental verification of the MCD key concept is presented for the first time by using commercially available power metal oxide semiconductor field effect transistors (MOSFETs) operating as MCDs. Measurements of the reverse recovery currents and reverse recovery charges of these “MCDs” are obtained and compared with the body diodes of the MOSFETs. These measurements suggest that MCDs can reduce the reverse recovery current, storage charge, and switching loss significantly. Optimized MCD performances at 1.2 kV, 2.4 kV, and 4.5 kV are also predicted based on numerical simulations. Ideal performance of the MCD close to that predicted by the device simulation should be obtained once an optimized MCD is developed 相似文献
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Cheol-Gyu Hwang Jeong-Seon Lee Jeong-Hoon Kim Noh-Hoon Myung Jong-In Song 《Microwave and Wireless Components Letters, IEEE》2003,13(6):229-231
Presents a fully monolithic K-band MMIC voltage-controlled oscillator (VCO) implemented by using a 0.25 /spl mu/m AlGaAs/InGaAs pseudomorphic HEMT (p-HEMT) technology. The use of a half-wavelength miniaturized hairpin-shaped resonator and a three-terminal p-HEMT varactor was effective in reducing the chip size and simplifying fabrication processes of the microwave MMIC VCO without impairing the performance of the circuit. The VCO provides a typical output power of 11.5 dBm at 20.8 GHz and a free-running phase noise of -82 dBc/Hz at 100 kHz offset and -95 dBc/Hz at 1 MHz offset. It also shows a tuning range of 70 MHz with little reduction in output power and high yield properties. The chip size of the MMIC VCO is 1.5 /spl times/ 2.0 mm/sup 2/. 相似文献
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D. Dahan E. Shumakher G. Eisenstein 《Photonics Technology Letters, IEEE》2006,18(4):592-594
We describe a 10-GHz multiwavelength pulse source based on high-order four-wave mixing products generated by a saturated optical fiber parametric amplifier. We employ a nonlinear modulation scheme for the pump which plays two roles. First, it enables us to use a high pump power with no phase modulation, and second, it yields narrow (6 ps) pulses with a constant spectral width and the same jitter level (/spl sim/150 fs) for the signal and three idler wavelengths. 相似文献
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Calleja A.J. Alonso J.M. Lopez E. Ribas J. Martinez J.A. Rico-Secades M. 《Power Electronics, IEEE Transactions on》1999,14(6):998-1006
A new single-stage high-power-factor electronic ballast based on a flyback converter is presented in this paper. The ballast is able to supply a fluorescent lamp assuring a high-input power factor for the utility line. Other features are lamp power regulation against line voltage variations and low lamp current crest factor, both assuring long lamp life. The ballast is analyzed at steady-state operation, and design equations and characteristics are obtained. Also, a procedure for the ballast design is presented. Finally, simulation and experimental results from a laboratory prototype are shown 相似文献
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Huizenga HM de Munck JC Waldorp LJ Grasman RP 《IEEE transactions on bio-medical engineering》2002,49(6):533-539
A method is described to incorporate the spatiotemporal noise covariance matrix into a spatiotemporal source analysis. The essential feature is that the estimation problem is split into two parts. First, a model is fitted to the observed noise covariance matrix. This model is a Kronecker product of a spatial and a temporal matrix. The spatial matrix models the spatial covariances by a function dependent on sensor distance. The temporal matrix models the temporal covariances as lag dependent. In the second part, sources are estimated given this noise model, which can be done very efficiently due to the Kronecker formulation. An application to real electroencephalogram (EEG) data shows that the noise model fits the data very well. Simulation results show that the resulting source estimates are more precise than those obtained from a standard analysis neglecting the noise covariance. In addition, the estimated standard errors of the source parameter estimates are far more precise than those obtained from a standard analysis. Finally, the source parameter standard errors are used to investigate the effects of temporal sampling. It is shown that increasing the sampling by a factor x, decreases the standard errors of all source parameters with the square root of x. 相似文献
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Markus Wirsing Armin Dammann Ronald Raulefs 《International Journal of Satellite Communications and Networking》2023,41(2):158-177
Global Navigation Satellite Systems (GNSS) have become an essential part of maritime navigation, in particular to improve situational awareness and vessel traffic management. The dependence on GNSS creates vulnerability for maritime shipping. Driven by this vulnerability, the desire for a backup system for maritime navigation has been emerging. The VHF Data Exchange System (VDES) standard provides communication capabilities for maritime applications. VDES is currently being revised. As part of this revision, VDES will be extended by ranging and navigation functionalities, called R-Mode, as an alternative for maritime navigation. In this paper, we address system design aspects and evaluate the positioning performance of VDES R-Mode. We derive estimation theory bounds on the accuracy of VDES R-Mode distance and velocity. In a case study, we discuss and evaluate the benefit of satellite links to complement VDES R-Mode positioning. Furthermore, we introduce a Kalman filter for position and velocity tracking, which we apply to experimental data. We describe an experiment we conducted at Lake Ammer, southwest of Munich, and evaluate the VDES R-Mode positioning performance for this setup. Our experimental results show that VDES R-Mode is capable of achieving a 95th-percentile horizontal position error of 22 m. Thus, VDES R-Mode is a promising approach for a maritime backup system that can meet the IALA accuracy requirements. 相似文献
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Crosignani B. Di Porto P. Ganiel U. Solimeno S. Yariv A. 《Quantum Electronics, IEEE Journal of》1972,8(9):731-739
The consequences of the deviation from ideal coherence of the driving (pump) field in nonlinear processes are examined. A detailed treatment of the processes of parametric amplification and frequency upconversion is presented. The treatment utilizes two different approximation methods to suit the two different physical situations considered. For slow phase variations of the pump field an adiabatic approach is useful, whereas in the treatment of fast phase variations (the nonadiabatic case) an equation describing the time evolution of theP representation is found to be a good starting point. In this latter case, a closed hierarchy of equations for the moments of the photon number distribution in the signal (or idler) mode is found. In particular, we find that the efficiencies of both the amplification and the upconversion processes are reduced as a result of pump incoherence, the reduction becoming more severe in the highly incoherent case. For the frequency converter, the very nature of the process is modified as compared to the ideal case, and this modification is again of particular significance for the highly incoherent pump. Second-order moments are explicitly calculated and some of the statistical properties of the output signals are examined. 相似文献
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60 GHz OCS mm-wave generation for ROF system based on saturated parametric amplification effect in HNLF 总被引:2,自引:0,他引:2
A novel approach to generate 60 GHz optical carrier suppression (OCS) millimeter-wave (mm-wave) signal based on the saturated
optical parametric amplification (OPA) effect in high non-linear fiber (HNLF) is investigated. In the proposed system, the
OPA effect occurs when the signal and pump with 30 GHz frequency interval are set into the high non-linear fiber. By controlling
the length of HNLF, OPA effect saturates, and the pump power is delivered in a large extent to the signal and idler light,
so a 60 GHz OCS mm-wave is generated. The system does not need high-speed external modulator, high-frequency vibration source
or narrow-band filter, which greatly reduces the cost and improves the stability of the radio over fiber (ROF) system. Results
show that the 10 Gb/s downstream signal can be transmitted with negligible power penalty. 相似文献
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Chindalore G.L. McKeon J.B. Mudanai S. Hareland S.A. Shih W.-K. Wang C. Tasch A.F. Jr. Maziar C.M. 《Electron Devices, IEEE Transactions on》1998,45(2):502-511
For the first time, experimental results are presented for electron and hole mobilities in the electron and hole accumulation layers of a MOSFET for a wide range of doping concentrations. Also presented is an improved methodology that has been developed in order to enable more accurate extraction of the accumulation layer mobility. The measured accumulation layer mobility for both electrons and holes is observed to follow a universal behavior at high transverse electric fields, similar to that observed for minority carriers in MOS inversion layers. At low to moderate transverse fields, the effective carrier mobility values are greater than the bulk mobility values for the highest doping levels. This is due to screening by accumulated carriers of the ionized impurity scattering by accumulated carriers, which dominates at higher doping concentrations. For lower doping levels, surface phonon scattering is dominant at low to moderate transverse fields so that the carrier mobility is below the bulk mobility value 相似文献
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Waldorp LJ Huizenga HM Dolan CV Molenaar PC 《IEEE transactions on bio-medical engineering》2001,48(6):737-741
Estimated generalized least squares (EGLS) electromagnetic source analysis is used to downweight noisy and correlated data. Standard EGLS requires many trials to accurately estimate the noise covariances and, thus, the source parameters. Alternatively, the noise covariances can be modeled parametrically. Only the parameters of the model describing the noise covariances need to be estimated and, therefore, less trials are required. This method is referred to as parametric egls (PEGLS). In this paper, PEGLS is developed and its performance is tested in a simulation study and in a pseudoempirical study. 相似文献
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Chiarulli D.M. Ditmore R.M. Levitan S.P. Melhem R.G. 《Lightwave Technology, Journal of》1991,9(12):1717-1725
The authors present results from two laboratory experiments of both single and parallel selection in a one of four optical addressing circuit operating at 250 MHz using coincident pulse addressing. The first experiment is an examination of the coincident pulse power, as a function of the synchronization of the arriving pulses. The second experiment demonstrates the ability to select arbitrary subsets of the detectors with a select pulse train operating at 250 MHz. The two experiments contrast the temporal and physical scalability of coincident pulse systems and show that the dominant effects are power distribution limits on the physical scale of these systems 相似文献