• 한국정보컨버전스학회논문지
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• 제5권2호
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• pp.101-108
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• 2012

In the present paper, it removed the low frequency noise under 1Hz which get up base wandering from the various noise which is included in ECG signals. It used wavelet filter, FIR filter and Adaptive FIR filter and compared the efficiency of the filter. The set condition of 3 kind filters which are the comparative object is the next contents. Used wavelet case, used generating functions db7 and after decomposition, the low frequency of 8 phases (cA8) replaced at 0. FIR filter case, filter coefficient set 1400, cutoff frequency (${\omega}$) set 0.002. Adaptive FIR filter case, collecting coefficients (${\mu}$) with 0.005. The comparative result from the output wave shape and FT spectrum, wavelet is excellent in base wandering removals compared FIR filter and Adaptive FIR filter. And SNR comparisons, wavelet filter(44.16) is high compare with other two filters(25.19 and 15.94).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.544-546
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• 2004

This paper designs and evaluates a complementary filter for fusion of inertial sensor signals. Specifically, the designed filter is applied to inverted pendulum control where the pendulum's angle information is obtained from low-cost tilt and gyroscope sensors instead of an optical encoder. The complementary filter under consideration is a conventional one which consists of low- and high-pass filters. However, to improve the performance of the filter on the gyroscope, we use an integrator in the filter's outer loop. Frequency responses are obtained with both tilt and gyroscope sensors. Based on the frequency response results, we determine appropriate parameter values for the filter. The performance of the designed complementary filter is evaluated by applying the filter to inverted pendulum control. Experiments show that the performance of the designed filter is comparable to that of an optical encoder and low-cost inertial sensors can be used for inverted pendulum control with the heir of sensor fusion.

• 대한전자공학회논문지SD
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• 제44권10호
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• pp.17-22
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• 2007

이 논문에서는 PHS용 new automatic tuning 방법을 가지는 baseband complex bandpass filter를 제안하였다. DC offset 문제를 해결하기 위한 Low_IF 구조로 CMOS로만 집적된 PHS용 수신기를 설계하였다. ACS 특성을 만족시키기 위해 3차 Chebyshev complex filter를 이용하여 baseband를 선택할 수 있는 filter를 설계하였다. 새롭게 제시한 Comer frequency tuning 방법은 공정의 변화에 보상을 해주는 방식이고, MOS 스위치에 의한 노이즈 레벨을 감소시킨다. 이 filter는 CMOS 0.35um 공정이며, 전력소모는 12mW였다.

• 전기학회논문지P
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• 제66권4호
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• pp.200-205
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• 2017

In this paper, we propose a technique to determine the normal and arc of an alternating current using a mixed filter composed of an average filter and a band-pass filter and a frequency analysis. The proposed method uses the moving average filter of the FIR filter structure for noise removal and the band-pass filter of the IIR filter structure for detecting only specific frequency components after normalizing the measured current signal based on the maximum value. After performing Fast Fourier Transform (FFT) using the band-pass filtered signal, the total energy is calculated using the magnitude component of the frequency, and the arc is detected using the magnitude of the calculated energy. In order to show the validity of the proposed method, we experimented with various data and found that arc and steady state can be easily discriminated by calculating spectral energy. Therefore, it is considered that the proposed method can be applied to arc diagnosis of low voltage electric wire.

• JSTS:Journal of Semiconductor Technology and Science
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• 제6권4호
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• pp.286-292
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• 2006

This paper presents the design of a low-voltage wide-band switched-capacitor (SC) filter for wireless communication receiver applications. The filter is the 5th-order Elliptic lowpass filter. With the clock frequency of 50MHz implying that an effective sampling frequency is 100MHz with double sampling scheme, the cut-off frequency of the filter is programmable to be 1.25MHz, 2.5MHz, 5MHz and 10MHz. For low-power systems powered by a single-cell battery, the SC filter was elaborately designed to operate at 1.2V power supply. Simulation result shows that the 3rd-order input intercept point (IIP3) can be up to 27dBm. The filter was fabricated in a $0.25-{\mu}m$ 1P5M standard CMOS technology and measured frequency responses show good agreement with the simulation ones. The current consumption is 34mA at a 1.2V power supply.

• 대한방사선기술학회지:방사선기술과학
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• 제26권2호
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• pp.63-69
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• 2003

영상재구성에 있어 잡음(noise)을 제거하고 공간 분해능과 대조도 분해능을 향상시킬 수 있는 filter에서 cut off 주파수 level에 따라 영상의 질에 영향을 미치는 경향을 반폭치(FWHM : full width at half maximum)측정방법을 이용하여 비교하였다. 선택한 filter의 종류는 Band-limited, Sheep-logan, Sheep-logan Hanning, Generalized Hamming, Low pass cosine, Parazen, 그리고 Butterworth filter이다. SPECT 영상을 기록하기 위한 점선원(point source)으로 방사성의약품 $^{99m}TcO_4$을 이용하였으며 점선원에 대하여 각각의 filter에서 cut off 주파수 준위별로 영상을 기록하고 axial transverse, coronal sagittal... fh의 section image의 profile 곡선에서 반폭치을 측정하여 비교하였다. 본 연구에서 사용한 filter들에 있어서는 cut off level에 따라 X, Y, 그리고 Z축 방향으로의 평균 FWHM의 길이가 $9.16\;mm{\sim}18.14\;mm$까지 측정되었는데 cut off level 0.7에서 Generalized Hamming filter와 Band limited filter의 경우 9.16 mm로 반폭치의 길이가 제일 짧은 것으로 나타났다.

• 한국군사과학기술학회지
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• 제16권3호
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• pp.285-294
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• 2013

In this paper, we present a tunable BPF with a novel structure. The filter is very useful to optimization of low frequency filter performance, because the fiilter has air-coils and tuning screws. This filter also has the merits of light weight and small size in comparison with conventional tunable filter at low frequency. This type filters are especially suitable for switched filter bank due to tuning structure. We designed 4 channel filter bank with two SP4Ts and 4 BPFs using novel structure. Tuning processes were subsequently executed. We obtained satisfactory performances as a result; consequently, the validity of our proposal was proved.

• 대한전기학회논문지:전력기술부문A
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• 제53권8호
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• pp.432-437
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• 2004

Since the characteristic frequency is decreased in proportion to the fault distance, the characteristic frequency component may be insufficiently eliminated by a low-pass filter on a long transmission line. In order to set a standard for the cut-off frequency of the low-pass filter, this paper proposes a method for obtaining the characteristic frequencies due to line faults. The application results of the proposed method are presented for line to ground (LG) faults and line to line (LL) faults on a 345 kV 200 km overhead transmission line. The EMTP is used to generate fault signals under different fault locations and fault inception angles. By comparison between the characteristic frequencies obtained from the proposed method and the EMTP simulation, it is shown that the proposed method accurately obtains the characteristic frequency.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.385-386
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• 2008

In this paper, a simple dual band filter chip is designed with 0603 case size using IPD technology. The dual-band filter achieves high frequency band at 2.5 GHz and low frequency band at 1.8 GHz. The insertion losses in high frequency band and low frequency band are -0.195 dB and -0.146 dB, respectively. The return losses in these bands are -22.7 dB and -22.8 dB, respectively. The simple dual-band filter based on SI-GaAs substrate is designed within die size of about 1.3 $mm^2$.

• Journal of Information Processing Systems
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• 제17권5호
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• pp.1004-1019
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• 2021

To solve the problems of the low image contrast, fuzzy edge details and edge details missing in noisy image fusion, this study proposes a noisy infrared and visible light image fusion algorithm based on non-subsample contourlet transform (NSCT) and an improved bilateral filter, which uses NSCT to decompose an image into a low-frequency component and high-frequency component. High-frequency noise and edge information are mainly distributed in the high-frequency component, and the improved bilateral filtering method is used to process the high-frequency component of two images, filtering the noise of the images and calculating the image detail of the infrared image's high-frequency component. It can extract the edge details of the infrared image and visible image as much as possible by superimposing the high-frequency component of infrared image and visible image. At the same time, edge information is enhanced and the visual effect is clearer. For the fusion rule of low-frequency coefficient, the local area standard variance coefficient method is adopted. At last, we decompose the high- and low-frequency coefficient to obtain the fusion image according to the inverse transformation of NSCT. The fusion results show that the edge, contour, texture and other details are maintained and enhanced while the noise is filtered, and the fusion image with a clear edge is obtained. The algorithm could better filter noise and obtain clear fused images in noisy infrared and visible light image fusion.