• Title/Summary/Keyword: Digital Filters

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Computer-Aided Design of Dgital Elliptic Filters (Digital타원 필터의 Computer-Aided Design)

  • 李鍾寅;金東龍
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.24 no.1
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    • pp.123-132
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    • 1987
  • In this paper, we studied on the design of elliptic digital filters using the bilinear z transformation method, and proposed a design procedure satisfying prescribed specifications. The magnitude characteristics of digital filters are compared with its of analog filiters by computer simulation. Finaly we considered the quantization effects of digital filters. In cascader realization of fixed-point digital filters under dynamic range constraints, the outpout noise for IIR digital filters depends on the pole-zero pairing and ordering of the second order sections. Therfore an optmization procedure to finding a good ordering and pairing is very desirable. Thus, we proposed a sub-optimization procedure for finding "near optimal" solution.

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Distortion anaysis of digital filters for ECG signals (ECG 신호를 위한 디지탈 필터의 distortion 해석)

  • 남현도;안동준;이철희;장태규
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10a
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    • pp.817-822
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    • 1992
  • Distortion analysis of digital filters for the ECG signal processing is presented. Several band pass and band reject filters are designed for the analysis. Computer simulations are performed to compare the distortions of the Butterworth type filters and linear phase optimal fitters. The designed filters are applied to power line interference cancelling in ECG signals.

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An Analytical Approach for Design of Nth-band FIR Digital Filters with Equi-Ripple Passband

  • Moon, Dong-Wook;Kim, Lark-Kyo;Lim, Cheng-Chew
    • Journal of Electrical Engineering and Technology
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    • v.4 no.3
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    • pp.423-428
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    • 2009
  • In FIR (Finite Impulse Response) filter applications, Nth-band FIR digital filters are known to be important due to their reduced computational requirements. The conventional methods for designing FIR filters use iterative approaches such as the well-known Parks-McClellan algorithm. The Parks-McClellan algorithm is also used to design Nth-band FIR digital filters after Mintzer's research. However, a disadvantage of the Parks-McClellan algorithm is that it needs a large amount of design time. This paper describes a direct design method for Nth-band FIR Filters using Chebyshev polynomials, which provides a reduced design time over indirect methods such as the Parks-McClellan algorithm. The response of the resulting filter is equi-ripple in passband. Our proposed method produces a passband response that is equi-ripple to within a minuscule error, comparable to that of Mintzer's design method which uses the Parks-McClellan algorithm.

The Design of Digital Filter Using Elliptic Functions (타원함수를 이용한 Digital 필터의 설계)

  • 김동용;이종연;신홍규
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.11 no.5
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    • pp.315-322
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    • 1986
  • In this paper, we have studied on the IIR digital filters design using Elliptic functions. In process of transformation to digital fouctions from analos Elliptic functions, Bilinear z transformation method has been silized. Designing of digital filter using the Bilinear z transformation the problems of aliasing can be avoidedm whereas the frequency distrotion is generated. The transformation form analog function to digital function is not equal in the region of the cut off frequency response caused by this effect. Avoiding the problem of this effect, we have used proewarping method. Finally, the magnitude characteristics of digital filters are compared with its of analog filters by computer simulation. The results have shown that the magnitude characteristics of digital filters by the prewarping method have made more remarkable improvement than its of analog filters.

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Design of Optimal Digital IIR Filters using the Genetic Algorithm

  • Jang, Jung-Doo;Kang, Seong G.
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.2 no.2
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    • pp.115-121
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    • 2002
  • This paper presents an evolutionary design of digital IIR filters using the genetic algorithm (GA) with modified genetic operators and real-valued encoding. Conventional digital IIR filter design methods involve algebraic transformations of the transfer function of an analog low-pass filter (LPF) that satisfies prescribed filter specifications. Other types of frequency-selective digital fillers as high-pass (HPF), band-pass (BPF), and band-stop (BSF) filters are obtained by appropriate transformations of a prototype low-pass filter. In the GA-based digital IIR filter design scheme, filter coefficients are represented as a set of real-valued genes in a chromosome. Each chromosome represents the structure and weights of an individual filter. GA directly finds the coefficients of the desired filter transfer function through genetic search fur given filter specifications of minimum filter order. Crossover and mutation operators are selected to ensure the stability of resulting IIR filters. Other types of filters can be found independently from the filter specifications, not from algebraic transformations.

Analysis and Design of Nth-band FIR Filters with Equi-Ripple Passband Response (Nth 밴드 FIR 필터의 균일 리플 통과 대역 응답을 위한 해석과 설계)

  • Moon, Dong-Wook;Kim, Lark-Kyo
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.54 no.10
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    • pp.630-638
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    • 2005
  • In FIR (Finite Impulse Response) filter applications, Nth-band F]U digital filters are known to be important due to their reduced computational requirements. The conventional methods for designing F]U filters use iterative approaches such as the well-known Parks-Mcclellan algorithm. The Parks-Mcclellan algorithm is also used to design Nth-band FIR digital filters. But a disadvantage of the Parks-Mcclellan algorithm is that it needs a good amount of design time. This paper describes a direct design method for Nth-band FIR Filters using Chebyshev polynomials, which provides a reduced design time over indirect methods such as the Parks-Mcclellan algorithm. The response of the resulting filter is equiripple in passband. Our proposed method produces a passband response that is equripple to within a minuscule error, comparable to that of the Parks-Mcclellan algorithm.

Implementation of sigma-delta A/D converter IP for digital audio

  • Park SangBong;Lee YoungDae
    • Proceedings of the IEEK Conference
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    • summer
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    • pp.199-203
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    • 2004
  • In this paper, we only describe the digital block of two-channel 18-bit analog-to-digital (A/D) converter employing sigma-delta method and xl28 decimation. The device contains two fourth comb filters with 1-bit input from sigma­delta modulator. each followed by a digital half band FIR(Finite Impulse Response) filters. The external analog sigma-delta modulators are sampled at 6.144MHz and the digital words are output at 48kHz. The fourth-order comb filter has designed 3 types of ways for optimal power consumption and signal-to-noise ratio. The following 3 digital filters are designed with 12tap, 22tap and 116tap to meet the specification. These filters eliminate images of the base band audio signal that exist at multiples of the input sample rate. We also designed these filters with 8bit and 16bit filter coefficient to analysis signal-to-noise ratio and hardware complexity. It also included digital output interface block for I2S serial data protocol, test circuit and internal input vector generator. It is fabricated with 0.35um HYNIX standard CMOS cell library with 3.3V supply voltage and the chip size is 2000um by 2000um. The function and the performance have been verified using Verilog XL logic simulator and Matlab tool.

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A Note on Oceanographic Applications of Digital Filters (디지탈필터의 海洋學的 應용)

  • Kim, Hee Joon;Kang, Yong Q
    • 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.

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Wavelet Transform Based Low Pass Filters and Interpolation Filters in Digital Image Communication Systems (디지털 영상 통신 시스템에서 웨이블릿 변환 기반 저역 필터와 보간 필터)

  • Yoo Hoon
    • Journal of Korea Multimedia Society
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    • v.9 no.4
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    • pp.443-450
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    • 2006
  • In digital image communication systems, YUV 4:2:0 or YUV 4:2:2 images filtered and subsampled versions of YUV 4:4:4 images are utilized and these images recover their size by an interpolation filter. Low pass filters and interpolation filters in the image communication systems are generally utilized. Thus, to improve the image quality, efficient low pass filters and interpolation filters are still required. In this paper, we propose new and efficient low pass filters and interpolation filters and their design method. The low pass filters and interpolation filters used in the MPEG-2 system were developed independently. We utilize wavelet transforms to jointly design low pass filters and interpolation filters. Simulation results show that the proposed filters are superior to the filters used in MPEG-2 in terms of PSNR. In addition, the length of the proposed interpolation filters is shorter than that of the filters used in the MPEG 2 system.

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Coefficient Estimation of IIR Digital Filters Using a Real-Coded Genetic Algorithm

  • Lee, Yun-Hyung;So, Myung-Ok;Jin, Gang-Gyoo;Rhyu, Keel-Soo
    • Journal of Advanced Marine Engineering and Technology
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    • v.31 no.7
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    • pp.863-871
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    • 2007
  • This paper proposes a methodology to estimate the system coefficients for the infinite impulse response(IIR) digital filters using real code GA. In the traditional real coded GA, it adapts the general genetic operations, whereas in this paper the proposed real coded GA applies improved genetic operations in order to search the optimal solution in given problems. Each of unknown IIR digital coefficients collected as forms of a chromosome. Two illustrative examples including the band pass and band stop IIR digital filters are demonstrated to verify the proposed method.