• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.6 s.99
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• pp.660-666
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• 2005

Recently, the need for subminiature storage systems has increased with the diversification of portable devices. An actuator for small optical disk drives has to satisfy performance requirements such as higher access speed, lower power consumption, and smaller size. In this paper, we proposed the miniaturized rotary type VCM actuator that had an effective focusing mechanism and secured sufficient bandwidth for small form factor (SFF) optical disk drive (ODD). Initial model was designed by electromagnetic (EM) and structural analyses. Such a model was improved using design of experiments (DOE) procedure based on a Blu-ray disk (BD) 1x specifications.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.811-814
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• 1998

This paper proposes a constant time-delay filter with low sensitivity, which can be used for hard-disk drive. The sensitivity of 2nd order lowpass filter by two kinds of method, one is based on lossy integrators and the other is lossy and lossless integrators is analyzed and designed. SPICE simulation shows fesibility of a filter by the proposed approach.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.2
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• pp.161-166
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• 2014

This Electromagnetic metal piece detection sensor, having high sensitivity even under high humidity and dust density, using LVDT was investigated. Metal detection characteristics using phase detection method, for 3 frequencies covering ELF and LF band, were experimentally measured. It was found that the sensitivity for metal and animal food, in which metal piece was included, was exponentially increased as frequency increased. Reducing cutoff frequency of LPF after PD was found to be effective to proportionally increase sensitivity. Also the sensitivity of metal piece detection was enhanced by optimizing BPF bandwidth and SNR. Metal piece detection limit using available ferrous test samples was found to be 0.7mm diameter from the experiment using 50kHz, in ELF band, which was known to have better selectivity to animal food. is an example of ABSTRACT format.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.70-74
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• 2004

There are many researches being in process to develop the information storage devices applying to the portable devices recently. Based on this need, the information storage devices have to be satisfied with the fast access time, the robustness of the system, high data transfer rate and lower media price. The total size of the drive must design to adapt the portable devices such as CF II card or PC II card size. This paper proposes the swing arm type actuator to insert the designed actuator in the drive of the CF II size. Hereafter the research will be going on to be suitable to the physical standard and design the focus magnetic circuit newly. The swing arm type actuator including this circuit is designed to have the dynamic characteristic satisfying the mechanical specification as well as the BD 1x. Finally, the adaptability to the portable devices was demonstrated by the finite element analysis and optimization of structural part.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.433-437
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• 2000

본 논문에서는 데이터 전송용 특정 소출력 무선국용 무선기기의 송수신단의 회로를 설계하고 제작하여 특성을 측정하였다. 주파수 대역은 424.7~424.95MHz이고, 반이중(Half Duplex Communication) 통신방식, PLL Synthesized, 20 Channel, 12.5kHz Channel Bandwidth 그리고 FSK Modulation/Demodulation 방식을 사용하였다. 송신단은 저잡음 증폭기와 전력증폭기를 사용하여 10mW의 출력으로 설계하였고, 발생되는 스퓨리어스를 감쇄시키기 위해 저역통과필터와 공진 회로로 구성하였다. 수신단은 Dual Conversion 방식을 사용하였다. 설계한 결과, 송신단의 출력은 9.71dBm, 스퓨리어스특성 47dBc 그리고 수신단은 감도가 -113dBm에서 Jitter가 $\pm$12.3%로 나타났다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.1
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• pp.11-19
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• 1992

This paper proposes a reduced order method which reduces passband error by changing controllability and observability gramian based on weighted functions in the linear time invariant system. In the case that the 4-order model is the reduced to 3-order model in the low-pass filter, the QEI in the proposed method is improved to 6.15724 compared to 10.16464 in the balanced realization method and the sensitivity is improved to 5.45962 compared to 7.790568. The frequency property curves show that the proposed method is superior to the balanced realization method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.753-759
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• 2020

A modified Chebyshev lowpass filter function with progressively diminishing ripples in the passband is proposed and analyzed in the frequency domain. Owing to the diminishing ripples, the passband magnitude characteristic of the proposed Chebyshev function has improved compared to the classical Chebyshev function. In addition, the phase characteristics of the proposed Chebyshev function were improved considerably compared to that of the Chebyshev function, and the time delay of the proposed function was much simpler and flatter. In addition, the proposed Chebyshev filter was realizable by the passive doubly terminated ladder network delivering maximum power transfer for the order n, even or odd, thus making themselves amenable to low-sensitivity active RC or switched capacitor filters through the simulation techniques. To verify the proposed Chebyshev filter characteristics, a 6th order passive doubly terminated ladder lowpass filter was designed and analyzed using the MATLAB and SPICE program. Thus, the proposed Chebyshev function can remove the drawbacks of the classical Chebyshev function and could be applicable to the design of a filter with an improved filter size, phase, and time delay characteristics for various signal processing.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1796-1803
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• 2006

This Paper describes a systematic method for designing the $H_{\infty}$ controller for the inverted pendulum which is a nonlinear and single-input double-outputs system. In particular, the open-loop system is conbined with a pre-filter to shape the open-loop transfer function for the sensitivity function ind the complementary sensitivity function to be kept the desirable frequency characteristics. Consequently, the loop shaping technique of the open-loop transfer function reduces the impacts of the model uncertainties, measurement noises and exogenous disterbances on the dynamic characteristics of the inverted pendulum. The results of simulation and experiment show the efficiency of the proposed control method comparing with conventional PID control method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.7
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• pp.1326-1331
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• 2001

This paper has been studied about design of a transceiver for data transmission. The transceiver has bandwidth of 424.7~424.95 MHz and uses half duplex communication method, PLL synthesized, 20 channel, 12.5 KHz channel bandwidth and FSK modulation/demodulation method. The transmission set is designed using low noise amplifier and power amplifier Also, it consists of low pass filter and resonation circuit for decrease of spurious signal. The receiver set is designed using dual conversion method. Finally, the transceiver set achieves the following characteristics 9.71dbm output power, 47dbc spurious property and $\pm$12.3 Jitter at sensitivity of -1134dbm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.5
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• pp.201-206
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• 2015

A new electronically stopband tunable filter is proposed with three-input single-output using Operational Transconductance Amplifier (OTA) in this paper. The proposed filter provides band pass, low pass and high pass multifunctional responses. Centre frequency ($f_c$) and quality factor (Q) of the realized filters could independently tuned without disturbing each other. Various network sensitivity and non-ideal characteristic analysis are done to check the sensitivity and parasitic effect of different circuit parameters. The CMOS realization of filter is done with 1.8V-0.18um process parameters and HSPICE simulation results are presented to assert the presented theory.