• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.12
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• pp.1359-1364
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• 2012

The C-band semi-lumped lowpass filter with broad stopband and compact size characteristic using chip inductor is proposed. To provide an additional attenuation pole in stopband by SRF, a separable inductor is added to proposed structure, and it has broad stopband characteristic. The third order elliptic function lowpass filter with chip inductor(L: 9.1 nH, SRF: 5.5 GHz, Q: 25) has insertion loss of 0.38 dB, cutoff frequency of 920 MHz, broad stopband(below 20 dB) of 1.43~7.8 GHz and the size is reduced 37.4 % compared to distributed inductor.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.6
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• pp.663-671
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• 1988

In this paper, in order to reduce the blocking effect of block coded images, we propose the method considering the lowpass and bandpass components of Granrath's human visual model. This method consists of two-stage enhancement procedure. The first step is lowpass filtering which smooths out the blocking effect, and the second step is a high frequency enhancement procedure to increase the contrast decreased by the lowpass filtering in the first step. In the first step, the one-dimensional Gaussian filter which aligthns parallel to the edge direction is considered to preserve the edge in the block and the two-dimensional Gaussian filter is used to smooth out the blocking effect near the block boundaries. In the second step, the lowpass and bandpass components of the Granrath's model are considered to increase contrast in a restored image. The performance comparison of the proposed method and the existing mehtods is made by a computer simulation with several block coded images. We can see that the enhancement in the subjective quality of images of the proposed method is more significant than the enhancement in the subjective quality of images of the proposed method is more significant than the existing methods, though the proposed method does not show better performance on the PSNR gain, the poor measure of picture quality for block coded images.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.2 s.5
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• pp.85-93
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• 2004

In this paper, microstrip stepped-impedance hairpin resonator (SIR) lowpass filter f.PF) by surface rnicromachining on GaAs substrate is sugsested. This filter has the advantages of compact side, easy fabrication, and sharp cutoff frequency response. The new SIR LPF shows the 3 dB passband of dc to 33 GHz, the insertion loss of 0.82 dB, and the return loss of better than 17 dB up to 25.57 GHz. This filter is useful for many microwave system applications.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.7
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• pp.1254-1259
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• 2008

A new CMOS current-mode integrator for low-voltage analog integrated circuit design is presented. The proposed current-mode integrator is based on cross-coupled gain-boosting topology. When it is compared with that of the typical current-mirror type current-mode integrator, the proposed current-mode integrator achieves high current gain and unity gain frequency with the same transistor size. As a application circuit of the proposed integrator, we designed the 1.8V 200MHz band current-mode lowpass filter. These are verified by Hspice simulation using $0.18{\mu}m$ CMOS technology.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.12
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• pp.2458-2467
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• 1994

This paper proposes a new design method for obtaining the impulse responses which satisfy the prescribed conditions designing for maximally flat FIR lowpass filters and highpass filters. The bandpass filters and band-reject filters have been directly derived from the addition and subtraction of impulse responses of a lowpass filter and a highpass filter. The two-dimensional maximally flat FIR lowpass filter, highpass filters, bandpass filters and band-reject filters with zero-phase have been designed by transforming the impulses of the one-dimensional filters designed in this research, which do not destroy lines and edges at the image signal processing.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.5
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• pp.965-970
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• 2018

In this paper, the transition of the folded substrate integrated waveguide (FSIW) using two substrates is suggested and applied to the bandpass filter. The FSIW has similar characteristics with the SIW and can be reduced the width of the SIW. The transition between the FSIW to the microstrip is designed by using shorted quarter wavelength line. Also, the bandpass filter is designed by using the FSIW and the elliptic lowpass filter of 5 section. Fabricated bandpass filter has the center frequency of 5.75 GHz and the bandwidth of 33.2%. Also, the insertion loss and return loss at the center frequency are 0.63dB and 19.1dB, respectively.

• Journal of Ocean Engineering and Technology
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• v.24 no.1
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• pp.166-171
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• 2010

In this paper, the front-end of a digital receiver with a 25 kHz carrier frequency, 5 kHz symbol rate, and any excess-bandwidth is designed using two basic facts. The first is known as the uniform sampling theorem, which states that the sampled sequence might not suffer from aliasing even if its sampling rate is lower than the Nyquist sampling rate if the analog signal is a bandpass one. The other fact is that if the sampling rate is 4 times the center frequency of the sampled sequence, the front-end processing complexity can be dramatically reduced due to the half of the sampled sequence to be multiplied by zero in the demixing process. Furthermore, the designed front-end is simplified by introducing sub-filters and sub-sampling sequences. The designed front-end is composed of an A/D converter, which takes samples of a bandpass filtered signal at a 20 kHz rate; a serial-to-parallel converter, which converts a sampled bandpass sequence to 4 parallel sub-sample sequences; 4 sub-filter blocks, which act as a frequency shifter and lowpass filter for a complex sequence; 4 synchronized switches; and 2 adders. The designed front-end dramatically reduces the computational complexity by more than 50% for frequency shifting and lowpass filtering operations since a conventional front-end requires a frequency shifting and two lowpass filtering operations to get one lowpass complex sample, while the proposed front-end requires only four filtering operation to get four lowpass complex samples, which is equivalent to one filtering operation for one sample.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.353-356
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• 2002

In this paper, we design an efficient, scalable one-dimensional discrete wavelet transform (1DDWT) filter using data reorder unit (DRU). At each level, the required hardware is optimized by sharing multipliers and adders because the input rate is reduced by a factor of two at each level due to decimation. The proposed architecture shows 100% hardware utilization by balancing hardware with input rate. Furthermore, sharing the coefficients of the highpass and the lowpass filters using the mirror filter property reduces the number of multipliers and adders by half. We designed a scalable DRU that efficiently reorders and feeds inputs to highpass and lowpass filters. The proposed DRU-based architecture is so regular and scalable that it can be easily extended to an arbitrary 1D DWT structure with M taps and J levels. Compared to other architectures, the proposed DWT filter shows efficiency in performance with relatively less hardware.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.315-318
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• 1999

The purpose of this study is to establish the design theory of a DR ceramic bandpass filter used for WLL basestations and to research on the design theory of bandpass filter. The design procedure is circuit parameters and structural parameters will be derived. It was observed that the filter characteristics at the simulations

• The Journal of the Acoustical Society of Korea
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• v.24 no.1
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• pp.38-42
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• 2005

CMOS analog lowpass filters using speech signal bandwidth for a Asymmetrical Digital Subscriver Line(ADSL) modem are presented. Designed active lowpass filters are composed of the CMOS complementary high-swing cascode stage which can increase transconductance of an active element. As a result, their cutoff frequency are 138kHz and 1,100kHz respectively. A low-voltage high-swing cascode integrator which improved on a gain and unit gain frequency used to design the filters. The designed filters are verified by HSPICE simulation with the $0.251{\mu}m\;CMOS\;n-well$ Parameter and a single 2.5V power supply.