• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.394-397
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• 2003

In this paper, we have proposed a clock recovery algorithm of OFDM/QPSK-DMR(Orthogonal Frequency Division Multiplexing/Quadrature Phase Shift Keying Modulation-Digital Microwave Radio)system using BL-PSF(Band Limited-Pulse Shaping Filter) and have analyzed the clock phase error variance performance of OFDM/QPSK and single carrier DMR systems. The existing OFDM/QPSK-DMR system using the windowing requires training sequence or CP(Cyclic Prefix) to synchronize a receiver clock frequency Because there is no training sequence or CP(Cyclic prefix) in our proposed DMR system, the proposed clock recovery algorithm is useful to the OFDM/QPSK-DMR system using BL-PSF, The simulation results confirm that the proposed clock recovery algorithm has the same clock phase error variance performance in a single carrier DMR system under AWGN(Additive White Gaussian Noise) environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.1
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• pp.105-113
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• 2000

This paper proposes the optimal design method of PSF(pulse shaping filter) with fixed-point coefficients, often used in digital communication system. Though RCF (Raised Cosine Filter) and Root-Squared RCF have less attenuation in stopband and are designed with floating point coefficients, those are selected by the reason that the design is simple. In this paper, 1 introduce the optimal design method for fixed point PSF including Root Squared type by using mixed integer linear programming. Through some design examples, it is shown that the proposed method better performs in ISI and requires less complexity. The complexity of the proposed filter is reduced to 20% as compared to conventional RCF and Root Squared RCF. For IS-95, that is the standard of CDMA system, the proposed filter reduces ISI up to 75% compared to the standard transmission filter.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.152-155
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• 1994

The presence of joint elasticity or the arm flexibility causes low damped oscillatory position error along a desired trajectory. We utilize a stochastic model for describing the fast dynamics and the approximation error. A second order shaping filter is synthesized such that its spectrum matches that of the fast dynamics. Augmenting the state vector of slow part with that of shaping filter, we obtain a nonlinear dynamics to which a Gaussian white noise is injected. This modeling approach leads us to the design of an extended Kalman filter(KEF) and a linear quadratic Gaussian(LQG) control scheme. We present the simulation results of this control method. The simulation results show us that our Kalman filtering approach is one of prospective methods in controlling the flexible arms.

• Communications for Statistical Applications and Methods
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• v.25 no.1
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• pp.99-107
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• 2018

This article considers a robust Kalman filter from the M-estimation point of view. Pak (Journal of the Korean Statistical Society, 27, 507-514, 1998) proposed a particular M-estimating function which has the data-based shaping constants. The Kalman filter with the proposed M-estimating function is considered. The structure and the estimating algorithm of the Kalman filter accompanying the M-estimating function are mentioned. Kalman filter estimates by the proposed M-estimating function are shown to be well behaved even when data are contaminated.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.4
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• pp.624-632
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• 1994

In this paper, we implement modulator of 155Mbps 64QAM RF MODEM, CCITT G. 707 SDH(Synchronous Digital Hierachy) 1 level, for DMR(DIgital Microwave Radio) STM-1 transmission, PSF(Pulse Shaping Filter) plays an important role to analyze modulator. We use 7 orders elliptic filter instead of Chebychev filter(roll-off facter a=0.5)in this paper. we obtain that roll-off factor, a is 0.33, group delay is less than 10nsec using this filter. Also we get -20dBm output level after passing the PSF, and 0dBm output level after passing the IF amplifier.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.12
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• pp.1045-1052
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• 2000

In this paper, we propose a method to apply the Input Shaping Technique (IST) to multi-input multi-output (MIMO) systems. In MIMO systems, there is a high possibility of multi-mode residual vibration. The IST filter designed for this multi mode may need a longer time to suppress the residual vibration. Previous works prove that we can shorten the time lag by using negative sequence. This negative sequence, however, causes another problem - it requires excessive control input. In this paper, we provide a remedy to reduce the size of control input by limiting the reference input by limiting the reference input and its derivative. The result of simulations and experiments on a 2 link flexible arm confirmed the effectiveness of the proposed method.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.8
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• pp.883-888
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• 1999

To obtain high positioning auccuracy for a long, flex bleman Ipulator, residual vibration must be removed from the tip motion. But it is difficult to control the vibration of low frequency. There are open-loop and closed loop methods in the elimination of the residual vibration. We inroduce input shaping technique has been used as a simple open-loop method of controlling the residual vibration of a flexible manipulator. Design of input shaper in the continuous time domain is complicated. This paper presents a new technique that designs input shaper in the z-domain and analyzes input shaping method in the z-domain. This technique is simple and easy to design input shaper.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.4 s.97
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• pp.155-162
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• 1999

Input shaping technique has been used as a simple method of controlling the residual vibration of a flexible manipulator. With the conventional methods previously proposed by several authors, the frequency range that shows a good performance is restricted. When the designed frequency being different from the natural frequency of a system, the performance of control degrades remarkably. This paper introduced a new technique that designs input shaping with robustness in the z-domain.

• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.261-264
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• 2001

In this paper, we introduce a simple design method f9r mot-squared type raised cosine filter with equiripple characteristics. Through some design examples, we show that the proposed filter has much better performance in ripple than the conventional SRCF at the expense of small increasing of ISI. In addition, the proposed Inter is compatible with conventional SRCF. Finally, we designs the filter for W-CDMPI which uses RRC (Root Raised Cosine) with a=0.22, in 12bit finite precision.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10A
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• pp.1598-1603
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• 2000

In this paper, an efficient pulse shaping filter architecture for SSB/BPSK-DS/CDMA is proposed. The filter satisfies the specifications in IS-95. The proposed architecture is based on polyphase decomposition and look-up table method. By exploiting the linear phase property of the decomposed filter coefficients, the chip area required for look-up table can be reduced by half compared with the conventional methods. By Synopsys simulations, it is shown that the use of the proposed method can result in reduction in the number of gates by 40%.