• Title/Summary/Keyword: Duty cycle range

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A study on interference analysis between FHSS atd DSSS short range radio devices (FHSS 및 DSSS 방식 소출력 무선기기간 간섭분석에 관한 연구)

  • Choi, Jae-Hyuck;Koo, Sung-Wan;Chung, Kyou-Il;Kim, Jin-Young
    • 한국정보통신설비학회:학술대회논문집
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    • 2009.08a
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    • pp.242-247
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    • 2009
  • In this paper, we investigate interference between short-range radiocommunication devices (SRDs) with frequency hopping spread spectrum (FHSS) and direct sequence spread spectrum (DSSS) methods when they are in the same frequency bands. In order to analyze interference from unwanted emission of SRD with DSSS to that of FHSS, Monte-Carlo (MC) simulation method is employed and interference probabilities are calculated. We simulate interference scenarios in accordance with several duty cycles and bandwidths. It is also assumed that the propagation model is free space The effect of distance between interfering transmitter and victim receiver is analyzed and bit error rate (BER) is simulated. From the interference analysis results, it is shown that duty cycle affects compatibility more than bandwidth does. Also, we can make sure of the separation distance which satisfies BER criterion when there are only one interfering transmitter and multiple interfering transmitters.

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A Study on Evaluating a Representative Smoke Value from an Inspection Vehicle Using Integration Method over a Cycle of Free-Acceleration Test Mode (무부하 급가속 측정 사이클로 운전되는 검사 대상 디젤 차량으로부터 배출되는 매연값 적분에 의한 차량 매연 대표값 특성 연구)

  • Lee, Choong Hoon
    • Journal of ILASS-Korea
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    • v.18 no.3
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    • pp.132-139
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    • 2013
  • Smoke emissions from light duty diesel vehicles were measured using light extinction method with the free acceleration test mode. The smoke emissions for each measurement cycle of the free acceleration method showed large variations according to driver's pedal pushing pattern. The smoke values for each measurement cycle initially increased and reach a peak value. Integration of the smoke emissions with time for each measurement cycle was performed to get a representative smoke value which was obtained by averaging the integrated results. Two kinds of integration time range were used. One is range over the whole measurement cycle of the free acceleration method. The other is only the acceleration range in the measurement cycle. Overall, variation of the representative smoke values obtained by the integration method was reduced comparing to the traditional representative smoke value which was obtained from a peak smoke value over the measurement cycle. Ten vehicles of the same model with 2.5 liter diesel engines, and seven vehicles of the same model with 2.7 liter diesel engines, were tested using the free acceleration test method.

Design of Frequency Synthesizer using Novel Architecture Programmable Frequency Divider (새로운 구조의 프로그램어블 주파수 분주기를 사용한 주파수 합성기 설계)

  • 김태엽;박수양;손상희
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.5C
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    • pp.500-505
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    • 2002
  • In this paper, a novel architecture of programmable divider with fifty percent duty cycle output and programmable dividing number has been proposed. Through HSPICE simulation, a 900MHz frequency synthesizer with proposed frequency divider has designed in a standard 0.25$\mu\textrm{m}$ CMOS technology. To verify the operation of proposed frequency divider, a chip had been fabricated using 0.65$\mu\textrm{m}$ 2-poly, 3-metal standard CMOS processing and experimental result shows that the proposed frequency divider works well. The designed voltage controlled oscillator(VCO) has a center frequency of 900MHz, a tuning range of ${\pm}$10%, and a gain of 154MHz/V. The simulated frequency synthesizer performance has a settling time of 1.5${\mu}\textrm{s}$, a frequency range from 820MHz to 1GHz and power consumption of 70mW at 2.5V power supply voltage.

Design of Frequency Synthesizer using Novel Architecture Programmable frequency Divider (새로운 구조의 프로그램어블 주파수 분주기를 사용한 주파수 합성기 설계)

  • 김태엽;박수양;손상희
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.6C
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    • pp.619-624
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    • 2002
  • In this paper, a novel architecture of programmable divider with fifty percent duty cycle output and programmable dividing number has been proposed. Through HSPICE simulation, a 900MHz frequency synthesizer with proposed (sequency divider has designed in a standard 0.25㎛ CMOS technology To verify the operation of proposed frequency divider, a chip had been fabricated using 0.65㎛ 2-poly, 3-metal standard CMOS processing and experimental result shows that the proposed frequency divider works well. The designed voltage controlled oscillator(VCO) has a center frequency of 900MHz a tuning range of $\pm$10%, and a gain of 154HHz/V. The simulated frequency synthesizer performance has a settling time of 1.5$\mu$s, a frequency range from 820MHz to IGHz and power consumption of 70mW at 2.5V power supply voltage.

A DLL-Based Multi-Clock Generator Having Fast-Relocking and Duty-Cycle Correction Scheme for Low Power and High Speed VLSIs (저전력 고속 VLSI를 위한 Fast-Relocking과 Duty-Cycle Correction 구조를 가지는 DLL 기반의 다중 클락 발생기)

  • Hwang Tae-Jin;Yeon Gyu-Sung;Jun Chi-Hoon;Wee Jae-Kyung
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.42 no.2 s.332
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    • pp.23-30
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    • 2005
  • This paper describes a DLL(delay locked loop)-based multi-clock generator having the lower active stand-by power as well as a fast relocking after re-activating the DLL. for low power and high speed VLSI chip. It enables a frequency multiplication using frequency multiplier scheme and produces output clocks with 50:50 duty-ratio regardless of the duty-ratio of system clock. Also, digital control scheme using DAC enables a fast relocking operation after exiting a standby-mode of the clock system which was obtained by storing analog locking information as digital codes in a register block. Also, for a clock multiplication, it has a feed-forward duty correction scheme using multiphase and phase mixing corrects a duty-error of system clock without requiring additional time. In this paper, the proposed DLL-based multi-clock generator can provides a synchronous clock to an external clock for I/O data communications and multiple clocks of slow and high speed operations for various IPs. The proposed DLL-based multi-clock generator was designed by the area of $1796{\mu}m\times654{\mu}m$ using $0.35-{\mu}m$ CMOS process and has $75MHz\~550MHz$ lock-range and maximum multiplication frequency of 800 MHz below 20psec static skew at 2.3v supply voltage.

Actively Clamped Two-Switch Flyback Converter with High Efficiency

  • Yang, Min-Kwon;Choi, Woo-Young
    • Journal of Power Electronics
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    • v.15 no.5
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    • pp.1200-1206
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    • 2015
  • This paper proposes an actively clamped two-switch flyback converter. Compared to the conventional two-switch flyback converter, the proposed two-switch flyback converter operates with a wide duty cycle range. By using an active-clamp circuit, the proposed converter achieves zero-voltage switching for all of the power switches. Zero-current switching of an output diode is also achieved. Thus, compared with the conventional converter, the proposed converter realizes a higher efficiency with an extended duty cycle. The performance of the proposed converter is verified by the experimental results with use of a 1.0 kW prototype circuit.

A Novel Three-Port Converter for the On-Board Charger of Electric Vehicles (새로운 전기 자동차 온보드 충전기용 3-포트 컨버터)

  • Amin, Saghir;Choi, Woojin
    • Proceedings of the KIPE Conference
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    • 2017.11a
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    • pp.111-112
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    • 2017
  • This paper presents a novel three-port converter for the OnBoard Charger of Electric Vehicles by using an impedance control network. The proposed concept is suitable for charging a main battery and an auxiliary battery of an electric vehicle at the same time due to its power handling capability of the converter without additional switches. The power flow is managed by the phase angle (${\Theta}$) between the ports whereas voltage at each port is controlled by the asymmetric duty cycle and the phase shift (${\Phi}$) between the inverter lags controlled by the impedance control network. The proposed system has a capability of achieving zero voltage switching (ZVS) and zero current switching (ZCS) at all the switches over the wide range of input voltage, output voltage and output power. The feasibility of the proposed system is verified by the PSIM simulation.

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Transmission of 40 Gbps RZ through Precompensation of Dispersion Accumulated in Transmission Links of Single Mode Fibers (단일 모드 광섬유 전송 링크에 축적된 분산의 precompensation을 통한 40 Gbps의 RZ 전송)

  • Lee, Seong-Real
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2010.10a
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    • pp.780-783
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    • 2010
  • Net residual dispersion (NRD) available to transmit RZ formats with different 24 wavelength as a function of duty cycles of RZ format and residual dispersion per span (RDPS) is induced by controlling precompensation only in 960 km optical transmission links of single mode fiber (SMF) with inline dispersion management (DM) for compensating of accumulated dispersion. It is confirmed that effective NRD range for different 24 wavelengths is gradually broadening as RDPS is more smaller, and as duty cycle of RZ format is more larger in the same RDPS.

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A Study of ZVS Two-Switch Forward Converter Using Auxiliary Switch (보조 스위치를 사용한 ZVS Two-Switch 포워드 컨버터에 대한 연구)

  • Jung, Min-Hyuk;Kim, Yong;Um, Tae-Min;Lee, Kyu-Hun;Lee, Dong-Hyun
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.965_966
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    • 2009
  • In this paper, a new soft-switching Two-switch Forward converter topology has been proposed. Compared with conventional two-switch forward converter, the proposed converter employs an auxiliary switch and a clamp capacitor to instead of two reset diodes, not only its duty cycle can exceed 0.5 to achieve wide range input voltage, but also soft switching can be achieved for all switches. Especially, voltage stress across main switches can be clamped at $1/2V_{in}$, voltage stress across auxiliary switch can be clamped at $V_{in}$. In addition, due to clamp capacitor series with the transformer, duty ratio can be extended with equation $V_o=\frac{V_{in}(1-D}D{N}$. Therefore, as a kind of better cost-effective approach, it is very attractive for high input, wide range and high efficiency application.

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High-powerfactor Control of Boost-type Rectifier without input Current Sensing (입력전류의 검출이 없는 승압형 정류기의 고역률제어)

  • Bae, Chang-Han;Lee, Gyo-Beom;Song, Jung-Ho;Lee, Gwang-Un
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.48 no.9
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    • pp.510-516
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    • 1999
  • In this paper, a new high-powerfactor control method for boost-type rectifier is proposed, which removes the necessity of input current sensing. This method generates a sinewave duty template only from the line voltage waveform and rectifier output, and reduces reactive power remarkably utilizing three compensation coefficients which are determined through experiments. These compensations make the input current to be in phase with the input voltage all over the load range. A prototype boost-type rectifier is designed and experimental results are presented.

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