• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.4
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• pp.552-559
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• 1998

Conducted noise in power line contains both the common mode(CM) and differential mode(DM) noise. These two modes of noise are caused by different noise sources and paths. Therefore, CM/DM noise must be deal with individually in EMI filter. In this paper the technique to separate power line noise is presented, which can be used to measure both the CM and the DM noise from total generated noise. Also, noise-separator is designed and experimental results showed 30 dB above of separation performance in 10 kHz~10 MHz.

• Journal of Biomedical Engineering Research
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• v.22 no.3
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• pp.241-247
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• 2001

ABR(auditory brainstem response) is one of the audiometry which measures objective hearing threshold level by acquiring electric evoked potentials emanated from auditory nerve system responding to an auditory stimulation. However, the obtained potentials which are largely interfered by power line noise, have extremely low SNR, thus ensemble average algorithm is generally used. The purpose of this study was to investigate the effect of iteration number in ensemble average on the reduction of the power line noise. The power line noise was modeled to be a 60 Hz sinusoidal signal and the energy of the modeled signal was calculated when it was averaged. It was verified by simulation that the energy had the periodic zero points for each stimulation rate, and 60 Hz signal induced by the power line was applied to the developed ABR system to confirm that the period of zero energy point was the same with that of the simulation. By the properly selected iteration number, power line noise could be reduced and more reliable ABR could be acquired.

• Journal of Satellite, Information and Communications
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• v.12 no.2
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• pp.42-45
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• 2017

It is known that power line communication systems have more noise than general wired communication systems due to the high voltage that flows in power line cables, and the noise causes a serious performance degradation. In order to mitigate performance degradation due to such noise, this paper proposes an artificial intelligence algorithm based on polynomial regression, which detects signals in the impulse noise environment in the power line communication system. The polynomial regression method is used to predict the original transmitted signal from the impulse noise signal. Simulation results show that the signal detection performance in the impulse noise environment of the power line communication is improved through the artificial intelligence algorithm proposed in this paper.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.1
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• pp.23-28
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• 2002

In order to survey the radiation characteristics of pure line noise of unwanted noise from overhead high voltage AC transmission lines, a disk type gap noise generator was manufactured. Disk size which decides capacitance between the noise generator and earth was selected through preliminary indoor experiments and analysis by using surface charge method. The capacitance is one of principal parameters related to the injection of a proper noise current into lines. On the basis of the capacitance obtained from calculation, 5mm of space was given to the gap of the noise generator to be installed o test line and an aluminum disk of 60cm radius was made. The field experiments were performed with the noise generator hung on the Kochang 765 kV full scale test line. As the results, the useful data which can be used to analysis the radiation characteristics of noise from transmission lines were obtained. Those are the directivity of antenna toward the line, lateral profiles, frequency spectra, height pattern and so on.

• Geosystem Engineering
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• v.21 no.5
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• pp.251-261
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• 2018

With the urbanization in recent years, the power line interference noise in electromagnetic signal is increasing day by day, and has gradually become an unavoidable component of noises in magnetotelluric signal detection. Therefore, a kind of power line interference noise elimination method based on independent component analysis in wavelet domain for magnetotelluric signal is put forward in this paper. The method first uses wavelet decomposition to change single-channel signal into multi-channel signal, and then takes advantage of blind source separation principle of independent component analysis to eliminate power line interference noise. There is no need to choose the layer number of wavelet decomposition and the wavelet base of wavelet decomposition according to the observed signal. On the treatment effect, it is better than the previous power line interference removal method based on independent component analysis. Through the de-noising processing to actual magnetotelluric measuring data, it is shown that this method makes both the apparent resistivity curve near 50 Hz and the phase curve near 50 Hz become smoother and steadier than before processing, i.e., it effectively eliminates the power line interference noise.

• Journal of Power System Engineering
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• v.7 no.3
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• pp.23-28
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• 2003

In heavy nuclear power plant, high energy through main steam line is provided to turbine that generate the electric power. Since plant had generated power, high noise has been occurred. Noise make equipments and work environment worse. For finding out the location and the cause of making noise, noise was measured along main steam line at open/close test of Main Steam Isolation Valve (MSIV hereafter). As the result, it was identified that the vortex shedding in the cavity of MSIV is main noise source. The profile change of MSIV seat ring was proposed as the method of noise reduction. After filletting MSIV seat ring, the noise level reduced $10{\sim}20dB$ compared before the change of profile.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.12
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• pp.620-625
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• 2004

In this paper, we studied the emissive electric field due to the communication signal and the noise in medium voltage power-line. There are many types of conductive noise in power-line channel, which gives rise to radiation. And if the DMT carrier signal was excited, the current by this term was added to the current by noise and, generate radiation. We calculated input impedance by means of signal input network model of medium voltage power-line channel for calculating these currents. We calculated currents by input impedance and, calculated the emissive electric field by this calculated currents. From the measurement results, we knew that the measured results are very similar to the calculated results and if the input signal power level was higher than -40 dBm, the emissive electric field exceeds FCC radiation limit level 69.5 dB$\mu$V/m.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.37-40
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• 2001

Subject of this paper is analysis of channel noise and impedance characteristics for high speed power line communication to concerned noise of transmission line and impedance in the frequency range up to 30MHz. Parameters of transmission line was inducted from experimentally power line channel measurement. Moreover, Analysis of compared based on measurement of channel characters with simulation test for appear characters.

• Journal of Korea Multimedia Society
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• v.23 no.3
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• pp.402-411
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• 2020

Power line noise in electrocardiogram signals makes it difficult to diagnose cardiovascular disease. ECG signals without power line noise are needed to increase the accuracy of diagnosis. In this paper, it is proposed DNN(Deep Neural Network) model to remove the power line noise in ECG. The proposed model is learned with noisy ECG, and clean ECG. Performance of the proposed model were performed in various environments(varying amplitude, frequency change, real-time amplitude change). The evaluation used signal-to-noise ratio and root mean square error (RMSE). The difference in evaluation metrics between the noisy ECG signals and the de-noising ECG signals can demonstrate effectiveness as the de-noising model. The proposed DNN model learning result was a decrease in RMSE 0.0224dB and a increase in signal-to-noise ratio 1.048dB. The results performed in various environments showed a decrease in RMSE 1.7672dB and a increase in signal-to-noise ratio 15.1879dB in amplitude changes, a decrease in RMSE 0.0823dB and a increase in signal-to-noise ratio 4.9287dB in frequency changes. Finally, in real-time amplitude changes, RMSE was decreased 0.3886dB and signal-to-noise ratio was increased 11.4536dB. Thus, it was shown that the proposed DNN model can de-noise power line noise in ECG.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.35-37
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• 2002

Most of the inhabitants living near power line complain wind noise from power line to be problems they can feel directly if there is no countermeasure to remove noise basically. Wind noise from power line happens by tower, insulators, conductor and others in their operating individually or complexly. Wind noise show us several forms like whistle, siren and bullfrog croaking as height of noise source is high and elastic wave tone with low frequency. This paper shows actual conditions and occurrence cause which may be investigated and analyzed on the wind noise, and also prepares mitigation methods and introduces a working sample to reduce a wind noise.