• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.109-112
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• 2007

Definition-Enhancement of the digitalized image has been being made researches continuously due to application a camera to a mobile-apparatus and the advent of a digital camera. In particular, the inputted image from a sensor goes through the process of ISP(Image Signal Process) prior to output as a visual image. The high-frequency components are offset by LPF(Low Pass Filter) that eliminates the noise of high spatial-frequency at the moment. In this paper, we propose an algorithm that outputs more vivid image by using adaptive-HPF(High Pass Filter) that has apt coefficients for diverse conditions of an image edge, nevertheless we do not employ any Edge-Detection algorithm to enhance a blurred image.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.4
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• pp.281-287
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• 1998

$BiNbO_4$ ceramics doped with 0.07wt% $V_2O_5$ and 0.03wt% CuO (BNC3V7) were sucessfully sintered at $900^{\circ}C$ through the firing process with Ag electrode. The BNC3V7 shows typically Dielectric constant of 44.3, Thermal Coefficient of resonance Frequency(TCF) of 2 ppm/$^{\circ} and $Qxf_o$ value of 22,000 GHz. The laminated chip Low Pass Filter (LPF) is very sensitive to chip processing parameters, was confirmed by the computer simulation as a function of Q(Quality factors), filter size, capacitor layer thickness, inductor pattern widths. The multilayer type LPF was fabricated by screen-printing with Ag electrode after tape casting and then compared with the simulated characteristics. The results show that characterization of band pass width was similar to that of designed ones.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2298-2304
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• 2011

This paper describes and presents the design of a miniaturized low pass filter (LPF) for microwave frequency region using a common defected ground structure (CDGS). In this study a half-sized LPF is obtained using CDGS, while the previous LPFs with the conventional DGS showed a mild size-reduction. The common DGS (CDGS) is realized on the common ground plane of two microstrip lines, i. e double-sided microstrip lines, which exist back-to-back to each other. In order to show the validity of the proposed design, an example of LPF using CDGS and double-sided microstrip lines is designed, fabricated and measured using the dielectric substrate with the dielectric constant of 2.2 and with the thickness of 31mils. The size of the designed LPF using CDGS is only 52.6% compared to that of the previous LPF with the conventional DGS. In addition, it is shown that the performances of the proposed LPF are well preserved after the size-reduction with the measured S11 and S21 of -22dB, min and -0.19dB, max, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.355-360
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• 2012

In this paper, an stepped-impedance low pass filter(SI-LPF) of triangular-patch type is proposed. A SI-LPF designed according to the standard SI-LPF design procedure is folded as a right angled triangle. The figure of merits of this structure are the adjustabilities of the cut off frequency, the stopband and the attenuation pole frequency of the proposed LPF by varying the resultant slots after folding the SI-LPF compactly for miniaturization. The size of the fabricated LPF is $13.75mm{\times}6.875mm$, which is 24.4 % reduced one compared to that of the conventional SI-LPF. The measured results of the LPF show return loss of less than -10 dB at passband, insertion loss of less than -10 dB at stopband and wide stopband from 3.5 GHz to 10 GHz (about $3f_c$).

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.5
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• pp.185-189
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• 2005

This paper focuses on the design for Rx/Tx switch module of GSM(global standard mobile) band, characterization of a miniature, low power and dual-band implementation of the front-end switch module with low-pass filer And the effort to make agreement between the simulated design and the measured data for these solutions takes the place through accumulated design and manufacturing data library. We present the design, modeling and measurement of switch module integrating GSM Rx/Tx switching circuit and LPF(low pass filter) on a LTCC(low temperature co-fired ceramic) substrate. For GSM application, insertion and return loss of the low pass filter designed was less than 0.3 dB which was less than 12.7 dB at 900 MHz. The LTCC switch module contained 10 embedded passives and 3 surface mount components integrated on 4.6$\times$4.8$\times$1.2 mm, 6-layer multi-layer integrated circuit. The insertion loss of switch module measured at 900 MHz was 11 dB. In both of the design approach yielded excellent agreement between measured and simulated results.

• Journal of radiological science and technology
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• v.30 no.4
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• pp.329-334
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• 2007

This paper is for investigation of the noise reduction effect all 20 filters by combining Low Pass Filter(LPF) 5 kinds, High Pass Filter(HPF) 4 kinds, Median Filter(MF) 11 kinds. Noise is added to reduce noise and minimize the quality degradation in medical imaging system. We also compared Peak Signal to Noise Ratio(PSNR), Mean Square Error(MSE) for all the combinations of different filters. As a result, noise decrease appeared in the LPF3*3#1 + HPF3*3#1 + Vertical3*1 of highest filter. We confirmed noise reduction effect by applying the proposed filter combination in many fields of medical imaging applications.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.221_222
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• 2009

최근 전력 컨버터 사용의 증가로 배전계통에서의 고조파 왜곡이 날로 심각해지고, 따라서 고조파에 민감한 전력계통 기기와 고객 부하를 보호하기 위한 고조파 저감대책이 필요하다. 본 논문에서는 능동 필터와 Low-Pass Filter(LPF)를 전력계통 과도해석 프로그램인 Electro-Magnetic Transients Program(EMTP) 내의 Transients Analysis of Control Systems(TACS) 소자를 사용하여 모델링하고 고조파 발생시 능동필터에 LPF의 설치 유/무에 따른 배전계통에서의 상전류와 중성선 전류의 변화를 분석하였다.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.540-541
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• 2010

본 논문에서는 계통의 전력품질을 향상시키기 위해 LPF (Low Pass Filter)를 적용한 순시전력제어기를 제안한다. 제안된 순시전력제어기는 부하에서 발생하는 무효전력을 계산하기 위해 1개의 LPF와 1개의 곱셈블록만을 사용한다. 따라서 기존의 평균전력제어기와 순시전력제어기에 비해 연산이 간단하고 회로구현이 쉬운 장점을 가진다. 본 연구에서는 제안된 순시전력제어기의 유용성을 확인하기 위해 단상 능동전력필터(Active Power Filter)에 적용하여 시뮬레이션 및 실험을 수행하였다.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.2
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• pp.107-114
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• 2014

This paper applies a compensated low pass filter (LPF) to current measurements for permanent magnet synchronous motor (PMSM) drives. The noise limits the bandwidth of current controllers and has more adverse influences on control performances under the light load condition because of the low signal-to-noise ratio. In order to eliminate the noise sensitivity, this paper proposes a digital LPF with a compensator of gain attenuation and phase delay which are unacceptable in current information for PMSM drives. Characteristics of the proposed LPF are analyzed in comparison with the general LPFs. The compensated LPF is basically designed by the orthogonal property of the measured currents in the ${\alpha}{\beta}$ stationary reference frame. In addition, an implementation issue of the proposed method is discussed. Experimental results using the proposed method show improvements of the current control performance from two perspectives, rapid step responses and reductions of harmonic distortion.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.12
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• pp.1292-1299
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• 2003

In this paper, we fabricated new GaAs-based dielectric-supported air gapped microstriplines(DAMLs) using the surface MEMS and the LPF for Ka-band using the fabricated DAMLs. We elevated the signal lines from the substrate, in order to reduce the substrate dielectric loss and obtain low losses at millimeter-wave frequency band with wide impedance range. We fabricated LPF with DAMLs for Ka-band. Due to reducing the dielectric loss of DAMLs, the insertion loss of LPF can be reduced. Miniature is essential to integrate LPF with active devices, so that we fabricated LPF with the slot on the ground to reduce the size of the LPF. We compared a characteristic to LPF with the slot and LPF without the slot.