• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.8 no.6
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• pp.63-70
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• 1994

컴퓨터나 정밀기기기의 빈번한 운용으로 배전선 반송통신 시스템의 신뢰도는 그 어느 때보다 크게 요구된다. 배전선에 나타나는 여러 종류의 잡음은 반송통신 정보를 쉽게 오염시켜 전체 시스템에 큰 영향을 미치게 된다. 본 논문에서는 평활 잡음과 60[Hz] 전원 주파수에 동기된 고조파 잡음제거를 위해 LMS와 NLMS알고리즘을 이용한 적응필터를 사용하였고 컴퓨터 시뮬레이션을 수행해 본 결과 신호 대 잡음비의 관점에서 LMS보다 NLMS의 탁월한 효과를 확인하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.2
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• pp.75-82
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• 1994

The existence of peroodic impulse noises in distribution line carrier (DLC) communication system is known to be the most serious obstacle for improving DLC communication quality in reliability and capacity. From the spectral points, impulse noises can be divided into baseband type and modulation type the noise width of whichs are much different each other. With each nose type, this study presents the basic characteristics in relation to what they originate from and how their spectrum properties are revealed. The baseband type impulse noise is normally caused from thyristor circuit running with low switching speed and the modulation type noise from the circuit of switching power supply. The base wave of modulation noise is shown to be the pulsuatic charging current to primary condenser in switching power circuit. The study result indicates also that placing the DLC carrier frequency away the band predominated by modulated noise especially from RCC type switching power circuit is very important in DLC design.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.8
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• pp.1518-1527
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• 1994

An algorithm for BPSK demodulation of which channel is an electric distribution line is developed, and realized in this paper. To realize the BPSK demodulation by microprocessor, BPSK signal that is received through the distribution line must be converted to digital signal. A hardware which converts BPSK signal to digital one has been designed in this paper, and an algorithm for BPSK demoduation of which channel is distribution line has been also developed in algorithm for BPSK demoduation of which channel is distribution line has been also developed in this paper by paying the attention to the fact that a modulated point appears up and down according to the rising edge and falling edge of the modulated binary signal if the carrier frequency is even times to the modulated binary signal, and by paying the attention to the fact that the signal duration or modulated point is twice of the other point. The microprocessor demodulation system with the algorithm has been realized. The system proved to have 0.02%(or less) bit error rate in real BPSK demodulation.