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[IEEE 2019 IEEE/MTT-S International Microwave Symposium - IMS 2019 - Boston, MA, USA (2019.6.2-2019.6.7)] 2019 IEEE MTT-S International Microwave Symposium (IMS) - 30Gb/s 60.2mW 151GHz CMOS Transmitter/Receiver with Digitally Pre-Distorted Current Mode PAM-4 Modulator for Plastic waveguide and Contactless Communications
摘要： 151 GHz CMOS transmitter and receiver are presented for ultra-short distance (~1 mm) contactless connection and plastic waveguide communications. To continue to scale the communication bandwidth, the 4-level pulse amplitude modulation (PAM-4) is utilized by implementing a current-mode PAM-4 modulator in the transmitter. The transmitter and receiver suffer non-linear characteristics and create amplitude distortions on PAM-4 signaling. A digital pre-distortion circuit is integrated in the PAM-4 modulator to correct such system non-idealities. 151 GHz antennas are realized on FR4HR substrate and used as air-to-air/chip-to-waveguide couplers. On top of contactless connection and plastic ribbon waveguide, plastic-embedded PCB channels are introduced by exploiting copper-coated slots on PCB and plastic ribbons to communicate through PCB substrates. The transmitter and receiver are fabricated in 28-nm CMOS process. The demonstrated system consumes 60.2 mW under 1.2 V supply while transferring 30 Gb/s of PAM-4 data, achieving 2.01 pJ/bit energy efficiency.
关键词： 151 GHz transmitter/receiver,PAM-4 modulation,contactless communication,plastic-embedded PCB,digital pre-distortion,plastic waveguide
更新于2025-09-12 10:27:22
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A laser current control algorithm to avoid color distortion in laser projection displays
摘要： Laser display technology has gradually become an important solution for large screen display. As a mature lighting technology in recent decades, phosphor has been widely used in the field of lighting and display. As a solid-state light source, it has the advantages of low power consumption, environmental protection, rich color, and dynamic modulation. The luminescent efficiency of phosphors varies with temperature, which results in the nonlinearity of phosphor emission when the light source is dynamically modulated and the color temperature drift of the display image. In this paper, a control model of color temperature of laser TV display changing with laser current and temperature is established. The color temperature of laser TV is corrected by using current compensation control algorithm. The problem of color temperature drift caused by the change of phosphor conversion efficiency with temperature is solved. The color temperature deviation is 1118 K in the luminance range of the light source before compensation. By compensating and controlling the laser current, the ratio of blue light and phosphor is constant when the luminance changes, thus ensuring the color temperature constant when the luminance of the laser light source changes. The color temperature deviation is 50 K in the luminance range. By analyzing the different luminance of the display image, the stability of the color temperature is improved.
关键词： laser phosphor,color distortion,dynamic compensation
更新于2025-09-12 10:27:22
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Effect of Laser Welding Sequences on Residual Stresses and Distortion of DP600 Steel Joints
摘要： Different materials have been welded by laser beam. This process allows to obtain high quality welds with lower thermal effect. Laser beam welding produces narrow and high penetration welds without filler material. However, this process modifies the mechanical and microstructural properties of the welded joints. Therefore, this is currently a research topic, mainly using Advanced High Strength Steel (AHSS). These materials are used in the automotive industry. As a result, it is important to study the thermometallurgical and mechanical behavior of welded steels. In addition, a tool used to approximate the thermal effect in the fusion zone (FZ) and heat affected zone (HAZ) has been the computational numerical simulation. In this work, two butt joints of DP600 steel plates of 200 mm × 150 mm and 2 mm thickness with different welding sequences were simulated using the SYSWELD finite element software. The results of both coupons were compared and it was determined that the distortion and residual stresses decreased in the second coupon by applying a different welding sequence with equal heat input.
关键词： SYSWELD,Laser welding,Finite element simulation,Residual stresses,DP600 steel,Distortion
更新于2025-09-12 10:27:22
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Residual stress and welding distortion of Al/steel butt joint by arc-assisted laser welding-brazing
摘要： The thermo-elastic?plastic finite element method (FEM) is used to simulate the thermo-mechanical behavior of Al/steel tungsten inert gas (TIG) arc-assisted laser welding-brazing (A-LWB) butt joint. The influence of material nonlinearity, geometrical nonlinearity and work hardening on the welding process is studied, and the differences in the welding temperature field, residual stress and welding distortion by A-LWB and by single laser welding-brazing (SLWB) are analyzed. The results show that the thermal cycle, residual stress distribution and welding distortion by the numerical simulation are in good agreement with the measured data by experiments, which verifies the effectiveness of FEM. Compared with the SLWB, A-LWB can make the high-temperature distribution zone of weld in width direction wider, decrease the transverse tensile stress in the weld and reduce the distribution range of longitudinal tensile stress. And the welding deformation also decreases to some extent.
关键词： arc-assisted laser welding-brazing (A-LWB),residual stress,welding distortion,Al/steel,temperature field,finite element method (FEM)
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE International Conference on Automatic Control and Intelligent Systems (I2CACIS) - Selangor, Malaysia (2019.6.29-2019.6.29)] 2019 IEEE International Conference on Automatic Control and Intelligent Systems (I2CACIS) - Limiting THD of Grid Connected Photovoltaic System using PWM Switching Frequency Selection Based on Solar Irradiance Changing
摘要： Photovoltaic (PV) system becomes the best alternative energy to produce electricity that can replace fuel resource. Grid Connected Photovoltaic (GC-PV) system will supply the AC power generated to the utility grid then distributed to the consumer. Solar irradiance in Malaysia varies daily and throughout the year. The consequence of low irradiance level is the output of the PV array is low and thus the input of the inverter relatively becoming low. The inverter will exhibit large non-linearity when the inverter is operating at low power input during low level of solar irradiance and Total Harmonic Distortion (THD) will increased. Pulse Width Modulation (PWM) techniques that are Continuous Pulse Width Modulation (CPWM) and Discontinuous PWM (DPWM) are implemented in the inverter control of the GC-PV system using MATLAB/Simulink environment to investigate the effect of switching frequency on THD at different level of solar irradiance. THD is limit within standard requirement by selecting appropriate value of switching frequency. Results shows that CPWM has better performance in THD and switching losses at selected switching frequency.
关键词： total harmonic distortion,inverter,pulse width modulation,switching frequency,grid connected photovoltaic,solar irradiance
更新于2025-09-11 14:15:04
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[IEEE 2019 54th International Universities Power Engineering Conference (UPEC) - Bucharest, Romania (2019.9.3-2019.9.6)] 2019 54th International Universities Power Engineering Conference (UPEC) - Harmonic Behaviour of RGB WLED
摘要： For the last few years, there has been a decrease in electricity consumption for lighting purposes. The reason for this decrease is the widespread use of energy saving lighting elements that have high efficacy factor. LEDs are one of these lighting elements and have a very important role on energy saving lighting. On the other hand, power quality problems have started to be experienced more frequently and seriously, so it has become an important issue nowadays. Light emitting diodes are a closely related in both subjects. In this study, the harmonic behavior of RGB WLEDs, which has gained importance recently and has become increasingly widespread, has been investigated. RGB WLEDs, which are quite different from monochrome LEDs in terms of package contents and driver circuit, are expected to behave differently in terms of harmonics. In order to observe that, an appropriate test setup has been established and the power quality measurements of an RBG WLED sample have been performed for different operating cases. In the conclusion of the study, the enlightening results about the harmonic behavior of RGB WLEDs were obtained.
关键词： RGB WLED,Light emitting diodes,Distortion measurement,Relative spectral power,Power conversion harmonics
更新于2025-09-11 14:15:04
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[IEEE 2019 International Topical Meeting on Microwave Photonics (MWP) - Ottawa, ON, Canada (2019.10.7-2019.10.10)] 2019 International Topical Meeting on Microwave Photonics (MWP) - Analysis of RF Photonic Link Linearization Using Truncated Fourier Series
摘要： This paper analyzes analog electro-optic modulator linearization techniques employing modulation of multiple distinct carriers with differing modulation efficiencies. We describe a general framework for calculating intermodulation distortion for this type of composite modulation approach. The problem of compensation of nonlinear distortions above 3rd order in electro-optic links to optimize spur free dynamic range is formulated using truncated Fourier series, where the choice of RF photonic link parameters is shown to be equivalent to a corresponding window function applied to the truncated Fourier series representation of a desired transfer function.
关键词： intermodulation distortion,Electro-optic modulation,modeling
更新于2025-09-11 14:15:04
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[IEEE 2018 International Power Electronics Conference (IPEC-Niigata 2018-ECCE Asia) - Niigata (2018.5.20-2018.5.24)] 2018 International Power Electronics Conference (IPEC-Niigata 2018 -ECCE Asia) - Optimized Variable On-Time Control for LED Lighting Driver
摘要： This paper focus on how to implement variable on-time control to predictive boundary conduction mode boost PFC converter for driving LED lighting applications. Normally, the constant on-time control is implemented in predictive PFC converter, which leads to high THD of input line current. Varies of variable on-time control methods have been proposed to improve the THD of input line current. However, most of the proposed variable on-time calculation methods are too complex to be implemented in predictive control. In order to implement the variable on-time control to predictive control, a simple but very accurate variable on-time calculation method is applied. The optimized variable on-time control takes very short calculation time in DSP controller, hence it can be implemented in predictive control. The effectiveness of the proposed method which can reduce THD of line current is demonstrated on a 100 V input and 400 V/30 W output PFC prototype.
关键词： Predictive control,power factor correction,boundary conduction mode,zero-crossing point,total harmonic distortion.,power factor
更新于2025-09-11 14:15:04
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Distortion‐Controlled Red‐Shift of Organic Dye Molecules
摘要： We show quantum chemically how structural distortion of an aromatic dye molecule can be leveraged to rationally tune its optoelectronic properties. Using a quantitative Kohn-Sham MO approach in combination with Time-Dependent DFT (TD-DFT), we have investigated the influence of various structural and electronic tuning parameters on the HOMO–LUMO gap of a benzenoid model dye, amongst others: (i) out-of-plane bending of the aromatic core; (ii) bending of the bridge with respect to the core; (iii) the nature of the bridge itself; and (iv) π-π stacking. Our study reveals the coupling of multiple structural distortions as a function of bridge length and number of bridges in benzene to be chiefly responsible for a decreased HOMO–LUMO gap and consequently the red-shifting of the absorption wavelength associated with the lowest singlet excitation (ca. 560 nm) in our model cyclophane systems. These physical insights together with a rational approach for tuning the oscillator strength were leveraged for the proof-of-concept design of the intense near-infrared (NIR) absorbing cyclophane dye 18 at 785 nm. Our design may contribute to a new class of distortion-controlled NIR absorbing organic dye molecules.
关键词： Cyclophane,NIR Absorption,Structural Distortion,HOMO–LUMO gap,Time-Dependent DFT
更新于2025-09-11 14:15:04
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Optimizing the Nonlinearity and Dissipation of a SNAIL Parametric Amplifier for Dynamic Range
摘要： We present a quantum-limited Josephson-junction-based three-wave-mixing parametric amplifier, the superconducting nonlinear asymmetric inductive element (SNAIL) parametric amplifier (SPA), which uses an array of SNAILs as the source of tunable nonlinearity. We show how to engineer the nonlinearity over multiple orders of magnitude by varying the physical design of the device. As a function of design parameters, we systematically explore two important amplifier nonidealities that limit dynamic range: the phenomena of gain compression and intermodulation distortion, whose minimization are crucial for high-fidelity multiqubit readout. Through a comparison with first-principles theory across multiple devices, we demonstrate how to optimize both the nonlinearity and the input-output port coupling of these SNAIL-based parametric amplifiers to achieve higher saturation power, without sacrificing any other desirable characteristics. The method elaborated in our work can be extended to improve all forms of parametrically induced mixing that can be employed for quantum-information applications.
关键词： gain compression,Josephson-junction,three-wave-mixing,parametric amplifier,SNAIL,dynamic range,quantum-limited,intermodulation distortion
更新于2025-09-11 14:15:04