• 전기학회논문지
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• 제62권7호
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• pp.1020-1026
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• 2013

Multirate filtering process on the biological signals like Electrocardiogram (ECG) and Photoplethysmogram (PPG) can be defined as the digital signal processing algorithm in which the sampling rate varies to omit or interpolate the intermediate values between the sampled data. With this aim, we suggest a new multirate filtering algorithm by deleting the extraneous data to eliminate the unwanted degradations such as granular noise due to the usage of high sampling frequency and simultaneously to detect the fiducial features of ECG and PPG with reducing the complexity of resolving fiducial points such as R-peak, Pulse peak and Pulse Transit Time (PTT). After the experimental simulations performed, we can conclude the fact that we can detect the fiducial features of ECG and PPG signal in terms of R-peak, Pulse peak and PTT without the loss of accuracy even if we do not maintain the original sampling frequency.

• 제어로봇시스템학회논문지
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• 제8권12호
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• pp.1004-1013
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• 2002

A multirate state feedback control (MRSFC) method is proposed for systems sensitive to disturbance and noise based on the multirate estimator design using current estimator. MRSFC updates the controller output slower than the measurement sampling fiequency of system output by a lifting factor $R=T_c/T_s$ The closed-loop MRSFC system is less sensitive to disturbance and noise due to filtering effect than the conventional single-rate control system The multirate estimator gain can be obtained by solving a conventional pole placement problem such that MRSFC has the same spectrum of eigenvalues in the s-plane as the single-rate control. We applied the proposed multirate state feedback controller to a galvanometer servo system Simulation and experimental results show that settling and tracking performances are improved compared with a conventional single-rate pole placement control (PPC).

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.190-190
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• 2000

This paper presents a multirate state feedback control (MRSFC) method for systems sensitive to disturbance and noise based on the multirate estimator design using the current estimator. MRSFC updates the controller output slower than the measurement sampling frequency of system output by a lifting factor R=T$\sub$c//T$\sub$s/. The closed-loop MRSFC system is less sensitive to disturbance and noise due to filtering effect than the conventional single-rate control system. The multirate estimator gain is obtained from solving a conventional pole placement problem such that MRSFC has the same spectrum of eigenvalues in the s-plane as the single-rate control. We applied the proposed multirate state feedback controller to a galvanometer servo system. Simulation and experimental results show that settling and tracking performances are improved compared with a conventional single-rate pole placement control (PPC).

• 대한의용생체공학회:의공학회지
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• 제17권2호
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• pp.209-214
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• 1996

The display of biological signals in raster scan monitors often involves a multirate sampling operation which consists of decimation .and interpolation. All electroencephalouaphic (EEG) samples of 10 to 30 seconds (2, 500 to 7, 500 samples at 250[Hz] sampling frequency) must be displayed in the computer screen to keep the aspect ratio of the paper polygraph output. Since the current afrorclable display technology Plots at most 2, 000 Pixels Per row, sDme signal samples need to be discarde4 This Paper studies methods to perform this operation characterizing them from the signal processing viewpoint and compares the display quality among several decimation techniques. Experimental results show that a nonlinear operation such as the peak detection method could be preferable to the canonical linear filtering to reduce aliasing.

• 한국전자파학회논문지
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• 제11권1호
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• pp.1-7
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• 2000

직접확산 부호분할 다원접속(DS-CDMA) 시스템과 시분할 다원접속(TDMA) 시스템을 동일 주파수 대역에서 증첩하여 전송한 때 DS-CDMA 수선선호는 TDMA 선호에 의한 협대역 간섭이 문제된다. 따라서 본 논문에 서는 DS- COMA 수선선호의 협대역 간섭파(NI)를 제거하는 방법으로 복소 다중비율 필터뱅크(CMRFB)를 이용한 노치 펀터를 채용하여 AWGN, COMA 다중접속간섭 및 TDMA에 의한 Nl가 존재하는 육상 이동통신 채널에서 DS-COMA 선호의 성능과 공존 가능한 TOMA 채널 수를 분석하였고 노치 필터를 채용한 시스템에서가 거의 완벽하게 제거됨음 알 수 있었다.

• 전기학회논문지
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• 제63권4호
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• pp.551-558
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• 2014

Baseline drift reduction and removal of power line noises in electrocardiogram are often necessary to avoid the distortions in extracting the fiducial features. With this aim, the multirate digital filtering algorithm is suggested to design and implement Finite Impulse Response or Infinite Impulse Response Filter by changing the sampling rate with omitting or interpolating intermediate ECG data. After the experimental simulations performed, we can conclude the fact that we can suppress the baseline wander and power line disturbances in ECG signal with reducing the computational complexities in which we do not keep the original and high sampling frequency.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1435-1438
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• 2005

In hands-free telephone systems, the received speech signal is fed back to the microphone and constitutes the so-called echo. To cancel the effect of this time-varying echo path, it is necessary to device an adaptive filter between the receiving and the transmitting ends. For a typical FIR realization, the length of the fullband adaptive filter results in high computational complexity and low convergence rate. Consequently, subband adaptive filtering schemes have been proposed to improve the performance. In this work, we use deterministic approach to analyze the relationship between fullband and subband adaptive filtering structures. With block adaptive filtering structure as an intermediate stage, the analysis is divided into two parts. First, to avoid aliasing, it is found that the matrix of block adaptive filters is in the form of pseudocirculant, and the elements of this matrix are the polyphase components of the fullband adaptive filter. Second, to transmit the near-end voice signal faithfully, the analysis and the synthesis filter banks in the subband adaptive filtering structure must form a perfect reconstruction pair. Using polyphase representation, the relationship between the block and the subband adaptive filters is derived.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.860-863
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• 2002

Realizations of multirate converters are proposed using periodically time-varying (PTV) structures. By exploiting the computational redundancy of the filtering operation in a multirate filter, it is possible to implement the filter with much less hardware. In the proposed implementations, several coefficients time-share in a periodic fashion the hardware of one multiply-and-add. Therefore, each multiply-and-add circuit performs different coefficient scalings at different time instants within a period. Compared to the direct form realization, the proposed realizations reduce the hardware of an interpolator and a decimator by a factor of approximately U and M, respectively, while retaining the same processing speed, where U and M are the upsampling and downsampling factors, respectively. The approach can be used to obtain realizations for sampling rate conversion by a rational factor of U/M, where U and M are relatively prime, in which case hardware reduction by a factor of approximately UM can be achieved.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 춘계학술대회
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• pp.311-314
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• 1996

The display of biological signals in monitors often involves a multirate sampling operation which consists of decimation and intenolation. All electroencephalographic (EEG) samples of 10 to 30 seconds must be displayed in the computer screen to keep the aspect ratio of the paper polygraph output. Since the current affordable display technology plots at most 2,000 pixels per row, some samples need to be discarded. This paper studies methods to perform this operation characterizing them from the signal processing viewpoint and compares the display quality among several decimations. Experimental results show that a nonlinear operation such as the peak detection could be preferable than the canonical linear filtering to reduce aliasing.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.648-650
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• 2003

Efficient multi-resolution image fusion aims to take advantage of the high spectral resolution of Landsat TM images and high spatial resolution of SPOT panchromatic images simultaneously. This paper presents a multi-resolution data fusion scheme, based on multirate image representation. Motivated by analytical results obtained from high-resolution multispectral image data analysis: the energy packing the spectral features are distributed in the lower frequency bands, and the spatial features, edges, are distributed in the higher frequency bands. This allows to spatially enhancing the multispectral images, by adding the high-resolution spatial features to them, by a multirate filtering procedure. The proposed method is compared with some conventional methods. Results show it preserves more spectral features with less spatial distortion.