• Proceedings of the Korean Magnestics Society Conference
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• 2005.12a
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• pp.143-143
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• 2005

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.269.1-269.1
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• 2008

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.6
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• pp.850-859
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• 1998

Broadband noise with frequency components in the range from several kHz up to tens of MHz is widespread in the AC power line. Noise filter or surge suppressor, often used to suppress the conducted noise, have a poor performance in reducing the common-mode. In this paper, we proposed a lumped-circuit analysis model for Noise Cut Transformer(NCT) which can be used to suppress both the common mode and normal-mode noise. The simulations with our model show a good agreement with experimental results. It has been also shown that our NCT is superior to noise filter and general isolation transformer in reducing the conducted noise.

• Journal of the Korean Ceramic Society
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• v.43 no.2 s.285
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• pp.74-78
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• 2006

A non-integrated type noise filter on a Coplanar Waveguide (CPW) transmission line is demonstrated by using a highly resistive $Co_{41}Fe_{38}Al_{13}O_8$ nanogranular thin film with the dimensions of $4\;mm (\iota)\times4\;mm(\omega)\times0.1\;{\mu}m(t)$. The noise suppression characteristics are evaluated without placing an insulating layer between the CPW line and the magnetic thin film. The insertion loss is very low being less than 0.3 dB and this low value is maintained up to 2 GHz. At a ferromagnetic resonance frequency of 3.3 GHz, the power loss is very large and the degree of noise attenuation is measured to be 3 dB. This level of noise attenuation is still small for real applications; however, considering the small magnetic volume used in this work, further improvement is expected by simply increasing the magnetic volume and by integrating the magnetic thin film into the CPW transmission line.

• Proceedings of the Korean Magnestics Society Conference
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• 2004.06a
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• pp.190-191
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• 2004

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.4
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• pp.146-154
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• 1998

Broadband noise with frequency components in the range from several kHz up the tens of MHz is a major obstacle factor in normal operation of the AC line to supply the power to electrical and electronic control equipments. Because this kind of noise could damage the device or could be a source of malfunction, many devices such as filter and surge suppressor are used to cut off the noise. But those devices could not disconnected from the power line, so they result in poor common-mode of NCT as well as insulation characteristics as a isolation transformer in addition faraday shielding and proposed analysis model of NCT having tow functions of surge and noise reduction. The simulated and experimental results for the surge suppression characteristics are compared and evaluated for designed protype 1[kVA] NCT.

• Journal of Magnetics
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• v.12 no.1
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• pp.21-26
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• 2007

Si-based electromagnetic noise suppressors on coplanar waveguide transmission lines incorporated with a $SiO_2$ dielectric layer and a nanogranular Co-Fe-Al-O magnetic thin film are reported. Unlike glass-based devices, large signal attenuation is observed even in the bare structure without coating the magnetic thin film. Much larger signal attenuation is achieved in fully integrated devices. The transmission scattering parameter ($S_{21}$) is as small as -90 dB at 20 GHz at the following device dimensions; the thicknesses of the $SiO_2$ and Co-Fe-Al-O thin films are 0.1 $\mu$m and 1 $\mu$m, respectively, the length of the transmission line is 15 mm, and the width of the magnetic thin film is 2000 $\mu$m. In all cases, the reflection scattering parameter ($S_{11}$) is below -10 dB over the whole frequency band. Additional distributed capacitance formed by the Cu transmission line/$SiO_2$/Si substrate is responsible for these characteristics. It is considered that the present noise suppressors based on the Si substrate are a first important step to the realization of MMIC noise suppressors.

• Journal of Broadcast Engineering
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• v.23 no.4
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• pp.511-518
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• 2018

This paper deals with improving speech intelligibility by applying binary mask to time-frequency units of speech in noise. The binary mask is set to "0" or "1" according to whether speech is dominant or noise is dominant by comparing signal-to-noise ratio with pre-defined threshold. Bayesian classifier trained with Gaussian mixture model is used to estimate the binary mask of each time-frequency signal. The binary mask based noise suppressor improves speech intelligibility only in noise condition which is included in the training data. In this paper, speaker adaptation techniques for speech recognition are applied to adapt the Gaussian mixture model to a new noise environment. Experiments with noise-corrupted speech are conducted to demonstrate the improvement of speech intelligibility by employing adaption techniques in a new noise environment.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.133-138
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• 2012

Exhaust facility has basically the role of flame deflector, and considering additional functions, it can be classified by noise/emission suppressor and altitude simulation facility. In this paper, principles of flame deflector, jet pump, emission suppression are presented for exhaust treatment facility. Principles of noise suppression caused by Mach wave mitigation, jet energy mitigation by water evaporation and condensation are shown. In addition, a concept of vertical exhaust treatment facility is presented applying basic principles aforementioned.

• Journal of the Korean Magnetics Society
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• v.9 no.1
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• pp.55-63
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• 1999

It is necessary to eliminate the broad band noise whose frequency is in the range of several kHz to tens MHz generated from the AC power line to supply the power to electrical and electronic equipments. Because this kind of noise could damage or malfunction such equipments. To suppress those noises, some conventional devices such as a filter or surge suppressor have been used. However, they can not be isolated from the common-mode noise widely spreaded in all power line, which results in poor common-mode rejection performance. In this paper, we proposed a design method of shielded isolation transformer and a jumped circuit analysis model for shielded isolation transformer applicable to filtering common-mode noise as well as normal-mode noise. The analysis model has been verified as a suitable one for shielded isolation transformer through comparison of the simulation with experiment. In addition, it has been shown that the reduction performance for conducted noise of prototype 3 kVA shielded isolation transformer is superior to a unshielded isolation transformer.