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Author: search.filters.author.Chompoo, S.

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    Adaptive feedback equalization receiver for DS-CDMA with turbo coded systems
    (2005-01-01)
    Chompoo, S.
    ;
    Benjangkaprasert, C.
    ;
    Anatrasirichai, N.
    ;
    Janchitrapongvej, K.
    In this paper, adaptive equalizer receiver for a turbo code direct sequence code division multiple access (DS-CDMA) by using Least Mean Square (LMS) adaptive algorithm is presented. The proposed adaptive equalizer is based on finite impulse response (FIR) filter structure in which included Conventional Adaptive Equalizer, Decision Feedback Adaptive Equalizer and Feedback Adaptive Equalizer. The objective of the proposed equalizer is to minimize the bit error rate of the data due to the disturbances of noise and intersymbol interference phenomenon on the channel of the digital communication system. The computer simulation results shown that the proposed feedback adaptive equalizer provides a good bit error rate than the others one such as conventional adaptive equalizer, decision feedback adaptive equalizer.
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    Blind equalizer using the variable step size constant modulus algorithm
    (2004-12-01)
    Benjangkaprasert, C.
    ;
    Chompoo, S.
    ;
    Anantrasirichai, N.
    ;
    Janchitrapongvej, K.
    In this paper, we present a new adaptive equalizer using the variable step-size technique. The propose adaptive equalizer is based on Finite Impulse Response (FIR) filter structure, emphasizes for the 16-Quadrature Amplitude Modulation (16-QAM) digital communication system. The objective is to improve the performance or bit error of the communication due to the disturbances of noise and intersymbol interference phenomenon on the channel. The proposed algorithm is based on the Constant Modulus Algorithm (CMA) and this new algorithm provides fast convergence speed, low mean square error, and good symbol error rate than that of the previous one. We consider the 16-QAM communication system transmit data through Additive White Gaussian Noise (AWGN) channel. Moreover, according to the simulation result, it is found that the performance of the variable step-size adaptive equalizer is confirmed.
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    Adaptive noise canceller with parallel block structure using variable step-size algorithm for a single sinusoidal detection
    (2004-12-01)
    Benjangkaprasert, C.
    ;
    Chompoo, S.
    ;
    Anantrasirichai, N.
    ;
    Takahashi, N.
    This paper proposes a new implementation of an adaptive noise canceller based upon a parallel block structure, which aims to raise the processing and convergence rates and to improve the steady-state performance. First, an IIR bandpass filter with a variable center angular frequency using adaptive Q-factor control and two adaptive control signal generators are realized by the parallel block structure. Secondly, a algorithm for adaptive Q-factor control with parallel block structure is proposed to improve the convergence characteristic. Furthermore, the steady-state performance of the filter is stabilized by using the normalized algorithm and the variable step size parameter for adaptive control of the center frequency. Finally, simulation results are given to demonstrate the convergence performance.
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    Continuously variable step-size adaptive algorithm with parallel block structure for a single sinusoidal detection
    (2004-12-01)
    Benjangkaprasert, C.
    ;
    Chompoo, S.
    ;
    Sangaroon, O.
    ;
    Takahashi, N.
    In this paper, a new implementation of an adaptive noise canceller based upon a parallel block structure is proposed The objective is to increase the processing and convergence rates and to improve the steady-state performance. First, an IIR bandpass filter with a variable center angular frequency using adaptive Q-factor control and two adaptive control signal generators are realized by the parallel block structure. Secondly, a algorithm for adaptive Q-factor control with parallel block structure is proposed to improve the convergence characteristic. Furthermore, by using the normalized transfer function and the continuously variable step-size parameter for adaptive control of the center frequency to stabilize the steady-state performance of the filter. Finally, simulation results are given to demonstrate the convergence performance. © 2004IEEE.
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    The combination of genetic algorithm and variable step-size algorithm for adaptive IIR notch filter
    (2003-12-01)
    Benjangkaprasert, C.
    ;
    Jorphochaudom, S.
    ;
    Chompoo, S.
    ;
    Sangaroon, O.
    ;
    Janchitrapongvej, K.
    In this paper, the combination algorithm for a second-order adaptive IIR notch filter is presented. The proposed algorithm is based on the genetic algorithm as an initial stage of adaptation process, as we approach the optimum step-size parameter, we using the new variable step-size algorithm. By this technique, the new algorithm achieves the optimum step-size parameter of the filter coefficient for an adaptive IIR notch filter. The results of computer simulation show that the new algorithm provides a good performance such as fast convergence rate, low mean square error and noise robustness. In addition, the new algorithm is also applied to cancel 50-Hz power line interference in the recording of electrocardiograms signal. © 2003 IEEE.