• ETRI Journal
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• 제34권6호
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• pp.800-806
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• 2012

Transmission performances of direct detection-based 100-Gb/s modulation formats are investigated and compared for metro area optical networks. The effects of optical signal-to-noise ratio sensitivity, chromatic dispersion, cross-channel nonlinearity, and transmission distance on the performance of differential 8-ary phase-shift keying (D8PSK), differential phase-shift keying plus three-level amplitude-shift keying (DPSK+3ASK), and dual-carrier differential quaternary phase-shift keying (DC-DQPSK) are evaluated. The performance of coherent dual-polarization quadrature phase-shift keying (DP-QPSK) with block phase estimation and coherent DP-QPSK with digital differential detection are also presented for reference. According to our analysis, all three direct detection modulation formats could transmit a 100-Gb/s signal over several hundred kilometers of a single-mode fiber link. The results also show that DC-DQPSK outperforms D8PSK and DPSK+3ASK, and the performance of DC-DQPSK is comparable to that of coherent DP-QPSK with digital differential detection. The maximum transmission distance of DC-DQPSK is over 1,000 km, which is enough distance for metro applications.

• 한국통신학회논문지
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• 제22권4호
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• pp.685-695
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• 1997

In this paper, a new CMOS continuous-time fully-differential current-mode integrator is proposed as a basic building block of the low-voltage high frequency current-mode active filter. The proposed integrator is composed of the CMOS complementary circuit which can extend transconductance of an integrator. Therefore, the unity gain frequency which is determined by a small-signal transconductance and a MOSFET gate capacitance can be expanded by the complementary transconductance of the proposed integrator. And also the magnitude of pole and zero are increased. The unity gain frequency of the proposed integrator is increased about two times larger than that of the conventional continuous-time fully-differential integrator with NMOS-gm. These results are verified by the small signal analysis and the SPICE simulation. As an application circuit of the proposed fully-differential current-mode integrator, the three-pole Chebyshev lowpass filter is designed using 0.8.$\mu$m CMOS processing parameters. SPICE simulation predicts a 3-dB bandwidth of 148MHz and power dissipation of 4.3mW/pole for the three-pole filter with 3-V power supply.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 추계학술대회
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• pp.386-389
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• 2013

본 논문에서는 Processor와 DDR2 사이에 인터페이스되는 고속신호의 Signal Integrity 해석을 위해 IC Chip의 IBIS Model과 Transmission Line의 S-Parameter를 이용하여 고속신호의 Transient 해석을 수행하고 Eye Diagram을 생성하였다. 고속으로 동작하는 DQ, DQS/DQSb 신호 및 Clock, Address, Control 신호의 Eye Diagram에서 Setup/Hold 구간동안 Timing Margin과 Voltage Margin을 측정하였으며 Over-/Under-shoot 및 Differential 신호의 Cross Point가 Spec에 만족하는지 확인하여 신호의 품질을 확보하였다.

• 대한전기학회논문지:전력기술부문A
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• 제52권12호
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• pp.691-697
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• 2003

This paper proposes a current differential relay for transformer protection that operates in accordance with a blocking method based on the difference-function of a differential current. For magnetic inrush and over-excitation, discontinuities in the first-difference function of the differential current arise at the points of inflection, which correspond to the start and end of each saturation period of the core. These discontinuities are converted into the pulses in the second- and third-difference functions of the differential current. The magnitudes of the pulses are large enough to detect saturation of the core. A blocking signal is issued if the magnitude of the third-difference function exceeds the threshold and is maintained for three quarters of a cycle. The performance of the relay is assessed under various conditions with magnetic inrush, internal faults and external faults. The proposed blocking method can improve significantly the operating time of a relay and achieve high sensitivity of a relay.

• Journal of applied mathematics & informatics
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• 제31권3_4호
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• pp.457-467
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• 2013

There exist many deterministic models for signaling pathways in systems biology. However the models do not consider the stochastic properties of the pathways, which means the models fit well with experimental data in certain situations but poorly in others. Incorporating stochasticity into deterministic models is one way to handle this problem. In this paper the way is used to produce stochastic models based on the deterministic differential equations for the published extracellular signal-regulated kinase (ERK) pathway. We consider strong convergence and stability of the numerical approximations for the stochastic models.

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2003년도 하계학술대회 논문집
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• pp.217-221
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• 2003

In this paper, the Viterbi decoder containing new branch metrics of the squared Euclidean distance with multiple order phase differences is introduced in order to improve the bit error rate (BER) in the differential detection of the trellis-coded MDPSK-OFDM. The proposed Viterbi decoder is conceptually same as the multiple Phase differential detection method that uses the branch metric with multiple phase differences. Also, we describe the Viterbi algorithm in order to use this branch metrics. Our study shows that such a Viterbi decoder improves BER performance without sacrificing bandwidth and power efficiency. Also, the proposed algorithm can be used in the single carrier modulation.

• 한국음향학회지
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• 제38권2호
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• pp.240-245
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• 2019

본 논문은 수중 음향센서 데이터의 원거리 케이블 전송에 관한 연구 결과이다. LVDS(Low Voltage Differential Signaling) 전송 방식으로 설계된 데이터 송수신기의 케이블에 대한 원거리 전송 신호를 측정하고 지터 특성을 분석하였다. 지터 특성을 저감하기 위하여, 원거리 전송에 따라 감쇠될 송신 신호를 역 보상하는 고역 강조(pre-emphasis) 기법을 적용하였으며, 전송 거리에 따라 송신 특성을 검증하였다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 춘계학술대회
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• pp.695-698
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• 2010

본 논문은 High-speed signal에 대한 기본적인 설계 방법론, Differential signaling, Impedence matching, Decoupling Method 등에 대하여 논한 후 High-speed signal 의 전송 품질을 개선하기 위한 GND via 의 효과에 대하여 논하고자 한다. S-parameter simulation 및 실제 제품 적용 후 파형의 변화를 관찰하여 GND via 의 효용성을 살펴보아 High-speed signal Design 할 때 Design limitation 상황에 대해 적절한 방법론을 말하고자 한다.

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2000년도 하계종합학술대회논문집
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• pp.357-360
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• 2000

In this paper, we want to implement a noise canceller by using FIR filter on DSP(Digital Signal Processor). The FIR filter was designed by Blackman window together with desired band width and center frequency. We adopt Motorola DSP56002 and Crystal CS4215 (A/D and D/A converter) for our purpose. we generate input sinusoidal signals and noises by differential equations and pseudo random sequences on DSP also. The input signal including sinusoidal and noise passes through the FIR filter. The FIR filer output is a sinusoidal signal with noise reduced.

• 한국전자파학회논문지
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• 제16권4호
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• pp.410-417
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• 2005

본 논문에서는 플라스틱 광섬유 묶음을 이용하여 차동검출기를 구성하고 무선광 연결 수신부에서 잡음광 소거에 활용하였다. 광섬유 묶음을 이용하여 수신광을 분리해서 2개의 포토다이오드에 연결하면, 동일한 지점에서 잡음광을 검출하는 효과가 발생하므로, 잡음광의 공간분포가 심하게 변하여도 2개의 포토다이오드의 위치 차이로 인한 출력 전압의 변동이 나타나지 않아 잡음 소거 효과가 높아진다. 광 필터가 부착된 단일의 광검출기에 비하여 광섬유 묶음을 사용한 수신부에서 신호대잡음비를 약 $10\;\cal{dB}$ 개선하였다.