• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.542-547
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• 2003

A new approach to design of a discrete-time robust $H_{\infty}$ filter in finite horizon case is proposed. It is shown that robust $H_{\infty}$ filtering problem can be cast into the minimization problem of an indefinite quadratic form, which can be solved by implementing the Kalman filter defined in Krein space. The proposed filter is readily derived by simply augmenting the state space model and has the robustness property against the parameter uncertainties of a given system.

• Korean Journal of Digital Imaging in Medicine
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• v.12 no.1
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• pp.19-25
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• 2010

This study is mainly for the reduction of exposure dose by using a heavy elements filter(Gd) in the digital radiology. They contained heavy elements filter of Gd and X-ray beam hardening filters such as Al and Cu. According to the results of experimental evaluation, X-ray property was not changed with variety of kVp in the case of the Gd filter. The surface dose and absorption dose were increased in order of Cu and Al. The contrast of image showed the higher value in order of Cu, Al and Gd. While the use of Gd has increased the numerical value of the CR image, and grayscale has decreased noise value of the DR image.

• 한국해양학회지
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• v.19 no.2
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• pp.133-140
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• 1984

Oceanographic applications of digital filters are studied with special emphasis on the convolution filter with Hamming window and the recursive filters. Convolution filters are simple to understand and easy to design but not efficient for a long data set. Recursive filters, despite of the complexities, have advantages on economy and filter characteristic. By means of digital filtering technique we find that the alongshore wind at Pusan and the sea surface temperature at Gampo in summers during 1973 to 1979 are negatively correlated at low frequencies (periods longer than 5 days) but not so at high frequencies.

• Economic and Environmental Geology
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• v.20 no.2
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• pp.119-123
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• 1987

Hankel transform of order 0 can be represented by a combination of Abel transform and Fourier transform. This Abel-Fourier method can offer computational advantages over a conventional digital linear filter method through the uses of a rapid Abel transform with shift variant recursive filter and of a fast Fourier transform. The Abel-Fourier method, however, is generally less accurate than a well-designed digital linear filter method. In geoelectrical applications, the digital linear filter method seems to be more flexible than the Abel-Fourier method.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.2
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• pp.143-150
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• 2004

In this paper, a recursive digital filter realization for an ionospheric channel model is proposed. This realization is in the form of a cascade of identical second-order all-pass filters, and is determined by only three parameters; two coefficients of an all-pass section, and the number of sections. The values of these parameters are optimized by a nonlinear optimization algorithm called the "downhill simplex method", so that the resulting time delay function closely approximates that of the ionospheric channel model. Comparing with the nonrecursive digital filter realization, it can be shown that the proposed recursive-digital-filter-realization is advantageous in points of view for the numbers of filter coefficients and the realization.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.2
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• pp.34-45
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• 2007

Digital decimation filter is inevitable in oversampled sigma-delta A/D converters for the sake of reducing the oversampled rate to Nyquist rate. This paper presented a Verilog-HDL design and implementation of an area-efficient digital decimation filter that provides time-to-market advantage for sigma-delta analog-to-digital converters. The digital decimation filter consists of CIC(cascaded integrator-comb) filter and two cascaded half-band FIR filters. A CSD(canonical signed digit) representation of filter coefficients is used to minimize area and reduce in hardware complexity of multiplication arithmetic. Coefficient multiplications are implemented by using shifters and adders. This three-stage decimation filter is fabricated in $0.25-{\mu}m$ CMOS technology and incorporates $1.36mm^2$ of active area, shows 4.4 mW power consumption at clock rate of 2.8224 MHz. Measured results show that this digital decimation filter is suitable for digital audio decimation filters.

• Journal of IKEEE
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• v.8 no.1 s.14
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• pp.145-151
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• 2004

For wide-band spread spectrum communication systems such as IMT-2000, a digital matched filter is a key device for rapid spreading code synchronization. Although a digital matched filter can be implemented easily, large power consumption at the higher chip rate and large summation delay of longer chip length are the bottleneck of practical use. In this paper, we propose a optimized partial correlation digital matched filter structure which can be constructed of the so-called generalized hierarchical Golay sequence. a partial correlation structure can reduce the number of correlators, but enlarge the size of flip-flops. In this paper, The proposed approach focuses on efficient circuit size, power dissipation, maintaining the operating throughput. A proposed digital matched filter reduce the size of flip-flops by rounding method. and it reduces about 45 percentages of power dissipation and chip area as compared with digital matched filter which is not rounded. rounding. The proposed architecture was verified by using Xilinx FPGA.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.2 no.1
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• pp.37-42
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• 2009

The digital filter is essential element in digital signal processing area. It needs a high computational burden caused by multiplying and adding. The multiplier in digital filter is a dominant element, which occupies an wide area at the field of VLSI design, needs high power-consuming and also decides critical path that affects to filter performance. In this paper we proposed the simultaneous transform method which is represented 2's complementary representation to CSD and MSD representation to solve a complexity problem and to improve a computational speed. The performance of proposed method was implemented in VHDL and applied to an digital filters, was evaluated the decreasing of critical path delay.

• Nuclear Engineering and Technology
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• v.4 no.3
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• pp.181-185
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• 1972

A digital bandpass filter method is investigated for the data treatment in tile measurement of the reactor transfer function. It was found that the technique is very effective in eliminating the effects of external noise. A computer code was programmed for this method. The frequency response of a digital filter is calculated, and the data treatment with this method using a digital computer was illustrated for triangular and square waveforms. Error and restriction involved in use of this method are discussed.

• The Journal of the Acoustical Society of Korea
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• v.6 no.2
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• pp.15-18
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• 1987

Multiplication free adaptive digital filtering algorithms are discussed. The proposed. The proposed algorithm uses delta modulation digital filter and the relevant filter weights are updated using the SIGN algorithms to realize an adaptive digital filter without multiplication operations. It is shown that the resulting algorithm can be implemented using simple up/down counting operations. The convergence characteristics of the proposed adaptive digital filtering algorithm and .others are investigated for a system identification problem.