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Author: search.filters.author.Koseeyaporn, J.

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    Enhanced mathematical model for studying fundamental behaviors of injection locked relaxation oscillator
    (2015-01-01)
    Kitipongwatana, A.
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    Koseeyaporn, P.
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    Koseeyaporn, J.
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    Wardkein, P.
    This article proposes the analytical model for studying behaviors of injection locked relaxation oscillator (ILRO). The proposed model enhanced from N. Soltani's model can be used to demonstrate behaviors of the ILRO in case the input frequency is higher than the natural frequency, namely, necessarily physical conditions for locking, locked ranges, detuning behaviors and frequency division. The proposed model is verified by simulation results of the ILRO based on 0.35um-CMOS technology of TSMC.
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    Novel algorithm for sinusoidal interference cancellation
    (2011-12-01)
    Nosan, A.
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    Punchalard, R.
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    Wardkein, P.
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    Koseeyaporn, J.
    A simple and efficient method for canceling sinusoidal interference is presented in this paper. The interference of known frequency is modeled as a sum of unknown amplitude and zeros phase sine and cosine components. The amplitude of those components are sequentially estimated interms of Wiener-Hopf solutions using cumulative average system. Additionally, in order to avoid any look-up tables for generating the sine and cosine signals, the coupled-digital oscillator is employed instead. It has been demonstrated that the proposed method can efficiently and rapidly cancel sinusoidal interference as compared with the previous method. © 2011 IEEE.
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    Heart detection and diagnosis based on ECG and EPCG relationships
    (2011-08-26)
    Phanphaisarn, W.
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    Roeksabutr, A.
    ;
    Wardkein, P.
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    Koseeyaporn, J.
    ;
    Yupapin, PP
    A new design of a system for preliminary detection of defective hearts is proposed which is composed of two subsystems, in which one is based on the relationship between the electrocardiogram (ECG) and phonocardiogram (PCG) signals. The relationship between both signals is determined as an impulse response (h(n)) of a system, where the decision is made based on the linear predictive coding coefficients of a heart's impulse response. The other subsystem uses a phase space approach, in which the mean squared error between the distance vectors of the phase space of the normal heart and abnormal heart is judged by the likelihood ratio test (Λ) value, on which the decision is made. The advantage of the proposed system is that a heart's diagnosis system based on the ECG and EPCG signals can lead to high performance heart diagnostics. © 2011 Phanphaisarn et al, publisher and licensee Dove Medical Press Ltd.
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    Unbiased plain gradient algorithm for a second-order adaptive IIR notch filter with constrained poles and zeros
    (2010-08-01)
    Loetwassana, W.
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    Punchalard, R.
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    Koseeyaporn, J.
    ;
    Wardkein, P.
    This article proposes an unbiased plain gradient algorithm for a second-order adaptive IIR notch filter with constrained poles and zeros. The proposed algorithm employs removing a dominant parameter that produces inherent bias. By using this technique, the performances are improved with slight expense in computational complexity. In this paper, theoretical analysis for deriving the estimations of bias and mean square error (MSE) at steady state are presented in closed form. Moreover, the stability bound of the algorithm is also derived. To confirm the analytical results, the computer simulations are provided to corroborate the effectiveness of the proposed algorithm. Furthermore, the performances of the algorithm are also compared with the plain gradient (PG) and modified plain gradient (MPG) algorithms. © 2010 Elsevier B.V. All rights reserved.
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    First order complex adaptive FIR notch filter
    (2010-07-30)
    Punchalard, R.
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    Silaphan, V.
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    Koseeyaporn, J.
    ;
    Wardkein, P.
    This paper presents a first order complex adaptive finite impulse response (FIR) notch filter (FIR-ANF) to track and estimate the frequency of complex sinusoidal signal corrupted by Gaussian noise. This research also presents gradient based adaptive algorithm for adjusting the filter coefficient. Computer simulation results have shown that, as compared with the conventional first-order complex adaptive infinite impulse response (IIR) notch filter (IIR-ANF), the proposed technique has faster convergence time, especially, when the initial value of algorithm is far from the true solution.
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    Statistical performance of the direct frequency estimation algorithm for the adaptive FIR notch filter
    (2010-07-30)
    Silaphan, V.
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    Punchalard, R.
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    Loetwassana, W.
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    Koseeyaporn, J.
    ;
    Wardkein, P.
    The Mean square error (MSE) of direct frequency estimation algorithm (DFE) for the adaptive FIR notch filter is presented in this paper. The developed analysis technique is capable of tracking the simulations very well in the steady state. The proposed method is based on the merging between the analysis technique for linear predictor and the second-order adaptive FIR notch filter. Computer simulations have been treated to corroborate with the theoretical analysis.
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    Amplitude demodulation based on time-varying forced input of second-order oscillator circuit
    (2009-12-01)
    Kittipute, K.
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    Koseeyaporn, J.
    ;
    Wardkein, P.
    In this article, a novel coherent amplitude demodulation based on time-varying force function of secondorder oscillator circuit and injection locking Phenomenon is proposed. The compactness of demodulation circuit is obtained because amplitude demodulation mechanism is inherent in one oscillator circuit. With injection locking property, frequency and phase of the oscillator is identical to that of the transmitted carrier. Based on time varying force function which is an AM signal, coherent demodulation is taken place. In laboratory experiment, the Colpitts oscillator at UHF band is employed where experimental results agree well with the proposed principle. ©2009 IEEE.
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    Novel digital FM demodulation
    (2009-12-01)
    Punchalard, R.
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    Koseeyaporn, J.
    ;
    Wardkein, P.
    A very simple method to demodulate the digital frequency modulated (FM) signal is presented in this paper. A unit delay operator, multiplier, lowpass filter, arccosine function, and adder are employed. The proposed method is easily adjusted and controlled. The computer simulations are conducted to demonstrate the performance of the proposed technique. ©2009 IEEE.
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    AC power load controlling by using PWM based on phase locked loop
    (2009-10-22)
    Kitipongwatana, A.
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    Koseeyaporn, P.
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    Koseeyaporn, J.
    ;
    Wardkein, P.
    This paper proposes power load controlling by using PWM signal to on-off an electronic switch. With this technique, load current can be easily adjusted. For PWM signal, it is derived by using PLL. With the property of PLL, PWM signal whose frequency is synchronized with that of load power is generated. Consequently, phase of signal which is fed to load can be controlled all range of 360 degrees or 180 degrees. In addition, the experiment results show that linear relation between phase of signal and DC voltage. ©2009 IEEE.
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    Pulse position modulation based on phase locked loop
    (2009-10-22)
    Wisartpong, P.
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    Koseeyaporn, J.
    ;
    Wardkein, P.
    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.