Koseeyaporn, Jeerasuda
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Koseeyaporn, Jeerasuda
Alternative Name
Koseeyaporn, J.
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Email
jeerasuda.ko@kmitl.ac.th
48 results
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Item type:Publication, Direct frequency estimation based adaptive algorithm for a second-order adaptive FIR notch filter(2008-02-01); This work deals with the problem of the frequency estimation of a sinusoidal signal corrupted by broad-band noise. The direct frequency estimation based adaptive algorithm for a second-order adaptive finite impulse response (FIR) notch filter (AFNF) is thus proposed. The proposed algorithm employs the bias removal technique to remove the bias existing in the estimated parameter. The performances including the rate of convergence and the mean square error (MSE) can be easily controlled by using only one parameter, i.e., step size parameter. Moreover, the proposed filter is simple to implement and suitable for real-time applications. In addition, the difference equations for the convergence in the mean and mean square, and the closed form expressions for the steady-state estimation bias and MSE are also carried out. Finally, the simulation results are provided to confirm the theoretical analysis. © 2007 Elsevier B.V. All rights reserved. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Modified adaptive IIR notch filter based on direct frequency estimation algorithm(2006-12-01); A modified adaptive IIR notch filter based on direct frequency estimation algorithm is presented. The proposed system uses the automatic gain control and the Kalman filtering technique to improve the convergence speed and reduce the steady-state mean square error (MSE) of the estimated frequency. The simulation results confirm that the performance of the proposed system has been improved over the conventional direct and indirect adaptive IIR notch filters. © 2006 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A novel versatile modulator circuit(2005-12-01); ; In this paper, a novel versatile modulator that can function either as delta modulator, sigma-delta modulator, amplitude modulator and frequency modulator is proposed. The principle of the proposed scheme is based on schmitt-trigger circuit and composed of a few components: three OTAs, one capacitor and two resistors. The advantage of this circuit is that the clock (carrier) signal employed for modulation is inherent in the circuit. The modulating signal is therefore an external input requirement. Based on the compactness of the circuit, it is suitable for IC realization. The computer simulation demonstrates the results which agree well with the theoretical analysis. © 2005 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A modification of momentum LMS with variable momentum factor(2006-12-01); This article, variable momentum factor to improve performance of momentum LMS is presented. The momentum factor of algorithm is varied according to a gradient decent designed to reduce the square estimation error during each iteration. So this proposed algorithm has high convergence rate and low steady state misadjustment. Simulation results showed good performance of the algorithm in both stationary and nonstationary environments. © 2006 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Direct frequency estimation based Kalman adaptive IIR notch filter: State-space approach(2006-01-01); A direct estimation based adaptive IIR notch Alter (DANF) based on state-space structure and discrete Kalman filtering is represented in this paper. It is well known that the state-space description not only provides a more detail explanation of the system characteristic compared to the input-output description but also has robustness to finite word-length effects. In addition, by using the discrete Kalman filtering, the fluctuation of an estimated parameter of the filter is reduced. In this paper, sinusoidal signal detection is employed to evaluate the performance of the proposed filter compared to the state-space structure of the DANF (SDANF). The computer simulation results confirm that the performance of the proposed filter has been improved over the SDANF. © 2006 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Adaptive howling suppressor in an audio amplifier system(2007-12-01); The acoustic feedback causes a howling phenomenon in an audio amplifier system. This problem does not only annoy hearing but also can damage an amplifier system. The IIR adaptive howling suppressor (AHS) in an audio amplifier system is thus proposed in this paper. The algorithm of adaptive process is achieved by using the variable momentum least mean square (VMLMS). With this algorithm, the performance improvement and higher convergence rate can be success. The proposed AHS, which is placed between a preamplifier section and a power amplifier section, acts as a narrow bandwidth notch filter whose frequency characteristic can reduce a howling spectrum. The simulation results show good improvement in the howling suppression of the proposed AHS system. Moreover, the performance comparisons show that the proposed system is performed over the AHS conventional FIR and FALE structures at the same environment condition. ©2007 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A new automated heart defect detection based on signals and systems concept(2006-12-01); ; - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Pulse position modulation based on phase locked loop(2009-10-22); It is well know that Pulse Position Modulation (PPM) play an important role in optical and wireless communication, because of they save the power for transmission and obtained the high utilization of bandwidth. Consequently, in this paper PPM based on phase locked loop (PLL) with carrier and without carrier are proposed. It can easily adjust carrier frequency by tuning reference signal frequency of PLL. The proposed circuit is compose of voltage control oscillator (VCO), RC low pass loop filter, two mono stable multi vibrator and RS F/F. In order to obtain the PPM with carrier, we only add both output mono stable multi vibrator together. The experimental result show that this proposed PPM circuit work well and it is a compact size, when we compare with various signals that it can generate, such as Pulse Width Modulation (PWM), PPM, with and without carrier. ©2009 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Wide-band amplitude control of the second-order oscillator circuit(2008-10-01); ; Koseeyaporn, PoolsakIn this paper, a new analysis technique of an ordinary second-order oscillator which is based on multi-time concept is proposed. This mathematical analysis results in a new closed-form solution of a system complete response. It is found that amplitude of the natural response is not constant but varied with the forced response of the system. For a constant forcing function proposed, the new analysis is identical to the conventional analysis. In the case of time-varying forcing function, however, it is different from the conventional approach. Based on such analysis, it implies that the amplitude of a second-order oscillator can easily be controlled by forced response of the system. Hence, the obtained result based on the proposed analysis technique provides a proper mathematical solution for the system, especially in a time-varying forcing function. Moreover, the mathematical analysis for the wide-band characteristic of a second-order oscillator is also described. The experimental results demonstrate the responses of the oscillator which agree well between the theoretical and simulation results. © 2007 Elsevier GmbH. All rights reserved. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A simple and economic PWM and ΣΔ modulator circuit based on modified source-couple oscillator(2006-01-01); ; In this article, a simple and economic Pulse Width Modulator (PWM) and Sigma Delta Modulator (ΣΔ) circuit which is based on the modified CMOS source couple voltage-control oscillator is presented. The circuit can work either as PWM or ΣΔ modulator, depending on the condition of the two bias currents which are forced of the source couples. Namely, the circuit is a PWM when these two bias currents are out of phase. Otherwise, it is a ΣΔ modulator when both bias currents are identical. In addition, another feature of the proposed circuit is that the modulated signal can be either in voltage or current format. Moreover, the proposed circuit provides wide range of frequency operation because of few numbers of CMOS in the circuit. Furthermore, the circuit is very suitable for realization in integrated circuits (ICs) form and can be employed for optical communication application. The simulation results of the circuit are demonstrated and agreed well with theoretical anticipation. © 2006 IEEE.