• 전기학회논문지
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• 제66권1호
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• pp.194-202
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• 2017

In this study, we measured and analyzed electrical noise signals present in devices and systems operated in industrial facilities. Based on the analytic findings, we studied the most effective improvement measures for eliminating such noise signals. Leakage current and ground current generate data interferences in communication systems, and therefore we measured leakage current and ground current. We also measured and analyzed electrical noises in power systems to predict noise pathways and interference routes. Furthermore, we proposed the most effective and reliable improvement measures for blocking off various noise signals and safely eliminating them by improving the internal wiring of the facilities and grounding systems. As a final step, we conducted the proposed improvement measures and confirmed that they helped to improve the operations of the device sand systems in service by re-measuring electrical noise signals and comparing them with those measured before the proposed improvement measures were implemented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.794-796
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• 1993

This paper deals with the characteristic analysis of noise filter for the reduction of conduction noise, especially, common-mode noise. Attenuation in the system containing noise filter is analyzed and equivalent circuits for common- and differential- mode noise are derived. To clarify the effects by parasitic components of the inductor and capacitor, digital simulations using Design Center are carried out.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권4호
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• pp.169-174
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• 2002

This paper presents a high-resolution capactive microaccelerometer using branched finger electrodes with high-amplitude sense voltage. From the fabricated microacceleromcter, the total noise is obtained as 9 $\mu\textrm{g}$/√Hz at the sense voltage of 16.5V, while the conventional microaccelerometers have shown the noire level of 25~800 $\mu\textrm{g}$/√Hz. We reduce the mechanical noise level of the microaccelerometer by increasing the proof-class based on deep RIE process of an SOI wafer. We reduce the electrical noise level by increasing the amplitude of AC sense voltage. The nonlinearity problem caused by the high-amplitude sense volage has been solved by a new electrode design of branched finger type, resulting in self force-balancing effects for the enhanced linearity and bandwidth. The fabricated microaccelerometer shows the electrical noise of 2.4 $\mu\textrm{g}$/√Hz at the sense voltage of 16.5V, which is an order of magnitude reduction of the electrical noise of 24.3 $\mu\textrm{g}$/√Hz measured at 0.9V. For the sense voltage higher than 2V, the electrical noise of the microaccelerometer is lower than the voltage-independent mechanical noise of 11 $\mu\textrm{g}$/√Hz. Total noise, composed of the electrical noise and the mechanical noire, has been measured as 9 $\mu\textrm{g}$/√Hz at the sense voltage of 16.5V, which is 31% of the total noise of 28.6 $\mu\textrm{g}$/√Hz at the sense voltage 0.9V. The self force-balancing effect in the blanched finger electrodes increases the stiffness of the microaccelerometer from 1.1N/m to 1.61N/m as the sense voltage increases from 0V to 17.8V, thereby generating additional stiffness at the rate of 0.0016$\pm$0.0008 N/m/V$^2$.

• JSTS:Journal of Semiconductor Technology and Science
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• 제9권1호
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• pp.61-66
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• 2009

We have investigated the noise sensitivity of low noise amplifier (LNA) at different frequency. This noise sensitivity analysis provides insights about noise parameters and it is very beneficial for making appropriate design trade-offs. From this work, the circuit designer can choose the adequate noise parameters tolerances.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.212-216
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• 2001

Because conventional switching converters have been usually using unbalanced circuit topologies, parasitic capacitance between the drain/collector of an active switch and the frame ground through its heat sink may generate the common-mode conducted noise. We have proposed a balanced switching converter circuit, which is an effective way to reduce the common-mode conducted noise. As an example, a boost converter version of the balanced switching converter was presented and the mechanism of the common-mode noise reduction was explained using equivalent circuits. This paper extends the concept of the balanced switching converter circuit and presents a buck-boost converter version of the balanced switching converter. The feature of common-mode noise reduction is confirmed by experimental results and the mechanism of the common-mode noise reduction is explained using equivalent circuits.

• Journal of Electrical Engineering and Technology
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• 제13권3호
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• pp.1383-1391
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• 2018

A new nonlinear filtering algorithm for effectively denoising images corrupted by the random-valued impulse noise, called dual sliding statistics switching median (DSSSM) filter is presented in this paper. The proposed DSSSM filter is made up of two subunits; i.e. Impulse noise detection and noise filtering. Initially, the impulse noise detection stage of DSSSM algorithm begins by processing the statistics of a localized detection window in sorted order and non-sorted order, simultaneously. Next, the median of absolute difference (MAD) obtained from both sorted statistics and non-sorted statistics will be further processed in order to classify any possible noise pixels. Subsequently, the filtering stage will replace the detected noise pixels with the estimated median value of the surrounding pixels. In addition, fuzzy based local information is used in the filtering stage to help the filter preserves the edges and details. Extensive simulations results conducted on gray scale images indicate that the DSSSM filter performs significantly better than a number of well-known impulse noise filters existing in literature in terms of noise suppression and detail preservation; with as much as 30% impulse noise corruption rate. Finally, this DSSSM filter is algorithmically simple and suitable to be implemented for electronic imaging products.

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1627-1633
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• 2017

This paper proposes a voice enhancing ear-protection system which is based on feedback active noise control(FBANC). The proposed system selectively suppresses the background noise and preserves the talking voice by controlling the adaptive algorithm with the voice activity period detection module. The noise reduction performance of the proposed noise canceling algorithm is analytically derived for the two key performance affecting parameters, i.e., electro-acoustic coupling distance and noise bandwidth. The proposed system is also implemented with a floating-point DSP system and its performance is experimentally tested to compare with the analytically derived results. The achieved levels of noise reduction for the three different noise bandwidths cases, i.e., 10Hz, 50Hz, and 90Hz, are high to show 17.05dB, 10.54dB and 8.99dB, respectively. The feasibility of the proposed system is also shown by the peak noise reduction achieved more than 25dB while preserving the voice component in the frequency range between 200-800Hz.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.730-733
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• 2002

In this paper, implementation of active noise barriers using active noise control techniques is presented. Multi-channel FX-LMS algorithms and Leaky LMS algorithms are used for adaptive filters to attenuate noise which is propagated from the outside of experimental enclosures. Experiments have done to show the effectivene a proposed active noise barriers.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2007년도 공동학술대회 논문집
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• pp.297-302
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• 2007

Recently, electrical resistivity survey is used in the various fields and applied to urban area with many electrical noises. Therefor it's necessary to observe the electrical noise effect of the geological structure. The physical scale modeling was conducted for measuring the electric noise effect of the two geological models at various distances, depths and diameters of the electric noise objects. The results are as following. 1. When conductive noise object was vertical to the strike of geological structure and moved to the strike direction, the effect of conductive noise object at various separated distances to the measurement line was disappeared at a half distance measurement line length regardless of electrode arrays. 2. When conductive noise object was vertical to the strike of geological structure and moved to the strike direction, the effect of conductive noise object at various depths was disappeared at 4unit apart from the measurement line regardless of electrode arrays. 3. When conductive noise object was vertical to the strike of geological structure and moved to the strike direction, the effect of conductive noise object at various diameters was disappeared at 4unit apart from the measurement line regardless of electrode arrays.

• KIEE International Transaction on Systems and Control
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• 제2D권2호
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• pp.115-119
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• 2002

In this paper we present a generalized directional morphological filtering algorithm for the removal of impulse noise, which is based on a combination of impulse noise detection and a weighted rank-order morphological filtering technique. For salt (or pepper) noise suppression, the generalized directional opening (or closing) filtering of the input signal is selectively used. The detection of impulse noise can be done by the geometrical difference of opening and closing filtering. Simulations show that this new filter has better detail feature preservation with effective noise reduction compared to other nonlinear filtering techniques.