• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
• /
• pp.401-403
• /
• 2006

When RF overlay technology is used in EPON-based optical access network, there coexist the directly modulated 1310-nm upstream data, the directly modulated 1490-nm downstream data, and the amplitude-modulated l550-nm downstream broadcast signal based on RF overlay technology. In this paper, we analyze the spectrum of 8B/10B IDLE line code signal and the SRS effect of l490-nm IDLE line code signal on 1550-nm signal. From the result of analysis, we propose a new technique that can be used to improve the CNR of the broadcast signal, which is based on self synchronous scramble method.

• 대한전자공학회논문지
• /
• 제26권9호
• /
• pp.1444-1452
• /
• 1989

This paper describes the implementation of a real time fetal ECG monitoring system in which an adaptive multi-channel noise canceller is realized using the Texas Instruments TMS32020 progrmmmable ditital signal processor. An ECG signal from the electrode placed on the mother's abdomen and three ECGs from those on the chest are applied as the desired signal and the referened inputs, respectively, of the multi-channel filter. The coefficients of the filter are updated using the LMS algorithm such that the output of the multi-channel filter copies the maternal ECG embedded in the abdominal ECG. The enhanced fetal ECG is obtained by subtracting the filter output from the abdominal ECG, and the difference signal is recorded. Both off-line and on-line experimental results are presented to verify the effectiveness of the parameters for the digital signal processing algorithms and the prototype system.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1995년도 하계학술대회 논문집 B
• /
• pp.616-619
• /
• 1995

This paper describes developement of on-line system for vibration signal analysis. In the power system, the main reason of transformer fault is due to a large amount of current by a short-circuit and a ground-fault. The electromagnetic force caused by fault-current deforms transformer windings and results in vibration pattern change. Therefore if the continuous on-line vibration monitoring on transformer is performed, an incipient failure can be detected. The developed system is composed of data acquisition devices, user interface program, signal processing program, diagnosis and trend analysis program, self diagnosis program and communication program.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
• /
• pp.296-296
• /
• 2000

This paper describes the features of a transmission line and a wiring, and a design rule based on a demanded condition for a wiring. Like as the simulation of a circuit, by tracking the wiring path among parts that are disposed on PCB, we analyze the feature of the corresponding wiring using the design formula and rule. We implement a signal integrity simulator, which is capable of electrical and electronic simulation for the feature of a wiring signal and the corresponding signal, and the results are demonstrated.

• KEPCO Journal on Electric Power and Energy
• /
• 제2권4호
• /
• pp.563-567
• /
• 2016

In this paper, the chaos-based secure scheme for power line communication is proposed for the first time. A digitalized chaotic generator based Lorenz system is utilized for generating nonlinear dynamic chaotic signal for masking the information signal instead of reported analog chaotic generators. A simple method of encryption and decryption is also given. In order to confirm the feasibility of the proposed scheme, the system is simulated using a simplified encryption/decryption method in Proteus. The gained results from simulation demonstrated that by using the chaos-based security method, the data can be encrypted and easily transmitted through the power line network efficiently.

• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1989년도 춘계학술대회
• /
• pp.27-28
• /
• 1989

In conventional line scan angiography, flow signal has been enhanced by the time_of_flight effect while the signal from stationary tissues has been suppressed by the saturation rf pulse followed by spoiling gradients. Due to the inhomogeneous rf field and the tissue dependent T1 relaxation time, however, stationary tissues can not be suppressed completely or uniformly, and the remnant stationary signal deteriorates the resultant angiogram. Here, the complete cancellation of stationary tissues is made possible by the spectral analysis of a series of repetitive line images of the same slice. The Fourier transformation of a set of line images results in the spectrum images, where stationary tissues are collected into the dc component while arteries are included in harmonic components because of the variation of the flow velocity and the resultant flow signal in arteries according to the cardiac cycle. The summation of harmonic components excluding the dc component results in the angiogram of arteries with the complete cancellation of stationary tissues.

• 전자공학회논문지A
• /
• 제29A권2호
• /
• pp.33-40
• /
• 1992

The design method of signal delay line system using indirect frequency synthesizer is presented. The variable signal delay line system with 2[nsec] step of delay time at center frequency 60[MHz], bandwidth 500[KHz] and range 5.24-5.81[x10S0-6Tsec] is designed and fabricated. The results were met with good characteristics to be variable delay time of average 2.01[nsec] per step.

• Journal of Power Electronics
• /
• 제4권4호
• /
• pp.256-260
• /
• 2004

A new communication system is suggested using a single-phase full-bridge inverter with high efficiency ferrite core for power line communication (PLC). The conventional system has a decreasing signal voltage problem due to internal resistance. The proposed system has almost zero internal impedance and replaces a linear amplifier.

• 전기전자학회논문지
• /
• 제20권4호
• /
• pp.416-419
• /
• 2016

전자 회로의 집적도와 동작 주파수가 증가함에 따라 신호 전달 특성을 향상시키는 것이 중요하다. 본 논문에서는 인쇄 회로 기판에서 패드의 곡률 변화에 따른 신호 전달 특성을 분석하였다. 시뮬레이션 결과, 곡률이 커질수록 신호 전달 특성은 개선되었고, 전송선로의 두께가 얇을수록 곡률 변화에 더 적은 영향을 받으며, 길이가 짧을수록 곡률 변화에 더 큰 영향을 받는 것을 확인할 수 있었다.

• 전기전자학회논문지
• /
• 제25권4호
• /
• pp.710-715
• /
• 2021

전력선 신호는 다양한 원인으로 인하여 이상 현상을 보일 수 있다. 대표적인 이상 현상으로는 일시적인 진폭의 증가 혹은 감소(swell/sag), 클립핑에 따른 진폭의 일시적인 평탄화(flat top), 고조파 왜곡(harmonic distortion) 등이다. 고품질의 전력 신호를 위하여는 이러한 이상 현상의 검출 및 대응이 필요하다. 본 연구에서는 변곡점 검출법을 활용하여 전력선 신호의 이상 현상을 검출한다. 변곡점은 국부적인 최대값/최소값 그리고 기울기가 변하는 지점으로 정의된다. 전력선 신호는 정현파이기 때문에 최대값과 최소값 부근에서 변곡점이 존재하며 이상 현상이 발생하는 곳에서 추가적인 변곡점이 발생한다. 본 연구에서는 대상 신호에서 검출된 변곡점과 정상 신호의 변곡점을 비교하여 이상 현상을 판단한다. 아울러 비용함수를 정의하여 이상 현상이 발생하는 시점을 추정한다. 컴퓨터 모의실험으로 다양한 이상 현상에 대한 제안된 방법의 유용성을 검증한다. 일시적인 진폭의 증가/감소의 경우, 변곡점의 위치는 정상 신호와 동일하며, 변곡점에서의 진폭에서만 차이가 발생한다. 고조파 왜곡이나 평탄화된 진폭의 경우 추가적인 변곡점이 발생하여 비용함수가 큰 값을 보인다. 이러한 이상 현상 간의 차이를 이용하여 이상 현상을 분류할 수 있다.