• Title/Summary/Keyword: P-D feedback

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반절연 InP를 이용한 초고속 DFB 레이저 다이오드의 제작 및 특성 연구

  • 주홍로;김형문;김정수;오대곤;박종대;김홍만;편광의
    • Proceedings of the Optical Society of Korea Conference
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    • 1995.06a
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    • pp.11-17
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    • 1995
  • 반절연 InP를 전류 차단층으로 사용하는 초고속 변조 Distributed Feedback (DFB) 레이저의 다이오드를 제작 하였다. Grating이 형성된 InP 기판에 유기금속 증착법 (MOVPE)을 사용하여 다중 양자 우물 구조 성장 시켜 메사구조를 연성 한후, 전류 차단층으로 반절연 InP를 성장 하였다. 제작된 레이저 다이오드는 평균 문턱전류 10 mA, 기울기효율 14%이며, 30mA 구동 전류에서 10GHz 이상의 3dB 대역폭 특성을 보였다.

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All-optical mach-zehnder interferometric wavelength converter monolithically integrated with loss-coupled DFB probe source (Loss-Coupled DEB LD집적 Mach-Zehnder 간섭계형 파장 변환기)

  • 김현수;김종회;심은덕;백용순;김강호;권오기;오광룡
    • Korean Journal of Optics and Photonics
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    • v.14 no.4
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    • pp.454-459
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    • 2003
  • We report the first demonstration of 10 Gb/s wavelength conversion in a Mach-Zehnder interferometric wavelength converter monolithically integrated with a loss-coupled DFB probe source. The integrated device is fabricated using a BRS (buried ridge stripe) structure with an undoped InP clad layer on the top of a passive waveguide to reduce high propagation loss. The device exhibited a static extinction ratio of 11 dB. Good performance at 10 Gb/s is obtained with an extinction ratio of 7 dB and a power penalty of 2.8 dB at a 10$^{-9}$ bit error rate.

Adaptive Techniques for Joint Optimization of XTC and DFE Loop Gain in High-Speed I/O

  • Oh, Taehyoun;Harjani, Ramesh
    • ETRI Journal
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    • v.37 no.5
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    • pp.906-916
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    • 2015
  • High-speed I/O channels require adaptive techniques to optimize the settings for filter tap weights at decision feedback equalization (DFE) read channels to compensate for channel inter-symbol interference (ISI) and crosstalk from multiple adjacent channels. Both ISI and crosstalk tend to vary with channel length, process, and temperature variations. Individually optimizing parameters such as those just mentioned leads to suboptimal solutions. We propose a joint optimization technique for crosstalk cancellation (XTC) at DFE to compensate for both ISI and XTC in high-speed I/O channels. The technique is used to compensate for between 15.7 dB and 19.7 dB of channel loss combined with a variety of crosstalk strengths from $60mV_{p-p}$ to $180mV_{p-p}$ adaptively, where the transmit non-return-to-zero signal amplitude is a constant $500mV_{p-p}$.

6-18 GHz MMIC Drive and Power Amplifiers

  • Kim, Hong-Teuk;Jeon, Moon-Suk;Chung, Ki-Woong;Youngwoo Kwon
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.2 no.2
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    • pp.125-131
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    • 2002
  • This paper presents MMIC drive and power amplifiers covering 6-18 ㎓. For simple wideband impedance matching and less sensitivity to fabrication variation, modified distributed topologies are employed in the both amplifiers. Cascade amplifiers with a self-biasing circuit through feedback resistors are used as unit gain blocks in the drive amplifier, resulting in high gain, high stability, and compact chip size. Self impedance matching and high-pass, low-pass impedance matching networks are used in the power amplifier. In measured results, the drive amplifier showed good return losses ($S_11,{\;}S_{22}{\;}<{\;}-10.5{\;}dB$), gain flatness ($S_{21}={\;}16{\;}{\pm}0.6{\;}dB$), and $P_{1dB}{\;}>{\;}22{\;}dBm$ over 6-18 GHz. The power amplifier showed $P_{1dB}{\;}>{\;}28.8{\;}dBm$ and $P_{sat}{\;}{\approx}{\;}30.0{\;}dBm$ with good small signal characteristics ($S_{11}<-10{\;}dB,{\;}S_{22}{\;}<{\;}-6{\;}dB,{\;}and{\;}S_{21}={\;}18.5{\;}{\pm}{\;}1.25{\;}dB$) over 6-18 GHz.

Dynamics of the IBR-2M reactor at a power pulse repetition frequency of 10 Hz

  • Yu.N. Pepelyshev;D. Sumkhuu
    • Nuclear Engineering and Technology
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    • v.55 no.9
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    • pp.3326-3333
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    • 2023
  • The results of the analysis of a mathematical modeling for the IBR-2M pulsed reactor dynamics for a transition from a power pulse repetition frequency of 5 Hz-10 Hz are presented. The change in the amplitude response of the reactor for variable pulse delayed neutron fraction was studied. We used a set of power feedback parameters determined experimentally in 2021 at an energy output of 1820 MW·day. At a pulse repetition frequency of 10 Hz, the amplitude of pulse energy oscillations significantly depends on the value of the delayed neutron fraction in pulse βp. Depending on βp both suppression and amplification of reactor power fluctuations in the frequency ranges of 0.05-0.20 and 1.25-5.00 Hz can be realized.

An Active Tunable Bandpass Filter Design for High Power Application (고출력 특성을 고려한 능동 가변 대역 통과 여파기 설계)

  • Kim, Do-Kwan;Yun, Sang-Won
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.3
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    • pp.262-268
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    • 2010
  • In this paper, a high power active tunable bandpass filter made of dielectric resonators and varactor diodes is designed using the active capacitance circuit generating negative resistance for tuning cellular TX, RX band. An active capacitance circuit's series feedback circuit using GaAs HFET whose $P_{1dB}$ is 32 dBm is used for compensating the losses from the varactor diodes of the tunable bandpass filter. The tuning elements, the varactor diodes are used as the back-to-back configuration to achieve the high power performance, The designed active capacitance circuit improves the insertion loss characteristics. The designed 2-stage active tunable dielectric bandpass filter at cellular band can cover from 800 MHz to 900 MHz. The insertion losses at 836 MHz and 881.5 MHz with 25 MHz bandwidth are 0.48 dB and 0.39 dB, respectively. The $P_{1dB}$ of the designed bandpass filter at TX and RX band are measured as 19.5 dBm and 23 dBm, respectively.

Linearizing and Control of a Three-phase Photovoltaic System with Feedback Method and Intelligent Control in State-Space

  • Louzazni, Mohamed;Aroudam, Elhassan
    • Transactions on Electrical and Electronic Materials
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    • v.15 no.6
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    • pp.297-304
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    • 2014
  • Due to the nonlinearity and complexity of the three-phase photovoltaic inverter, we propose an intelligent control based on fuzzy logic and the classical proportional-integral-derivative. The feedback linearization method is applied to cancel the nonlinearities, and transform the dynamic system into a simple and linear subsystem. The system is transformed from abc frame to dq0 synchronous frame, to simplify the state feedback linearization law, and make the close-loop dynamics in the equivalent linear model. The controls improve the dynamic response, efficiency and stability of the three-phase photovoltaic grid system, under variable temperature, solar intensity, and load. The intelligent control of the nonlinear characteristic of the photovoltaic automatically varies the coefficients $K_p$, $K_i$, and $K_d$ under variable temperature and irradiation, and eliminates the oscillation. The simulation results show the advantages of the proposed intelligent control in terms of the correctness, stability, and maintenance of its response, which from many aspects is better than that of the PID controller.

A Channel State Information Feedback Method for Massive MIMO-OFDM

  • Kudo, Riichi;Armour, Simon M.D.;McGeehan, Joe P.;Mizoguchi, Masato
    • Journal of Communications and Networks
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    • v.15 no.4
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    • pp.352-361
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    • 2013
  • Combining multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) with a massive number of transmit antennas (massive MIMO-OFDM) is an attractive way of increasing the spectrum efficiency or reducing the transmission energy per bit. The effectiveness of Massive MIMO-OFDM is strongly affected by the channel state information (CSI) estimation method used. The overheads of training frame transmission and CSI feedback decrease multiple access channel (MAC) efficiency and increase the CSI estimation cost at a user station (STA). This paper proposes a CSI estimation scheme that reduces the training frame length by using a novel pilot design and a novel unitary matrix feedback method. The proposed pilot design and unitary matrix feedback enable the access point (AP) to estimate the CSI of the signal space of all transmit antennas using a small number of training frames. Simulations in an IEEE 802.11n channel verify the attractive transmission performance of the proposed methods.

High-Performance Control of Three-Phase Four-Wire DVR Systems using Feedback Linearization

  • Jeong, Seon-Yeong;Nguyen, Thanh Hai;Le, Quoc Anh;Lee, Dong-Choon
    • Journal of Power Electronics
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    • v.16 no.1
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    • pp.351-361
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    • 2016
  • Power quality is a critical issue in distribution systems, where a dynamic voltage restorer (DVR) is commonly used to mitigate the voltage disturbances for loads. This paper deals with a nonlinear control for the three-phase four-wire (3P-4W) DVR under a grid voltage unbalance and nonlinear loads in the distribution system, where a novel control scheme based on the feedback linearization technique is proposed. Through feedback linearization, a nonlinear model of a DVR with a PWM voltage-source inverter (VSI) and LC filters is linearized. Then, the controller design of the linearized model is performed by applying the linear control theory, where the load voltages are kept constant by controlling the d-q-0 axis components of the DVR output voltages. To keep the load voltage unchanged, an in-phase compensation strategy is employed, where the load voltages are recovered to be the same as the previous voltage without a change in the magnitude. With this strategy, the performance of the DVR becomes faster and more stable even under unbalanced source voltages and nonlinear loads. The validity of the proposed control strategy has been verified by simulation and experimental results.

Monolithic Integrated Amplifier for Millimeter Wave Band (밀리미터파 대역 단일 집적 증폭기)

  • Ji, Hong-Gu;Oh, Seung-Hyeub
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.10
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    • pp.3917-3922
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    • 2010
  • In this paper, 3 stage amplifier MMIC was designed and fabricated with U-band optimized epitaxal pHEMT that produced by large signal characterization and modeling for 60 GHz band. The pHEMT used in this paper, the gate $0.12\;{\mu}m$ length and total gate width of $100\;{\mu}m$, $200\;{\mu}m$ has been modeled using the large signal designed with negative feedback and MCLF instead of MIM capacitor for improving stability. Fabricated MMIC $2.5{\times}1.5mm^2$ size, current about 40 mA, operating frequency 59.5~60.5 GHz, gain 19.9~18.6 dB, input matching characteristics -14.6~-14.7 dB, output matching characteristics -11.9~-16.3 dB and output -5 dBm characteristics were obtained.