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Item type:Publication, A simple frequency adjustable self-oscillation class D amplifier using OTA(2014-02-04) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Flow rate controlling using phase-locked loop(2013-03-28) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Improved wien bridge oscillator with variable output amplitude(2013-03-28); An improved Wien bridge oscillator with variable output amplitude is presented in this article. The proposed technique uses an offset compensation circuit, an amplitude detector, and an error integrator to produce DC bias voltage of the opamp of the Wien bridge oscillator. Surpassing the traditional Wien bridge oscillator, the proposed method offers significant improvement in output amplitude, which can be adjustable. In addition, compared with the previously reported sinusoidal oscillators with variable output amplitude using multiplier circuit, the proposed method affords significant improvement in circuit configuration. Its benefits are simpler structure and lower costs. Experimental results verifying performance of the proposed technique agreed with expected values. © 2013 ICIC International. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Simple square-rooting voltage-to-frequency converter using opamps(2010-12-01); This paper presents a simple method based on commercially available operation amplifiers (Opamps) for realizing the square-rooting voltage-to-frequency converter (VFC). The realization of square-root function is provided through the use of the opamp supply-current sensing, which utilizes an inherent quadratic characteristic of the opamp class-AB output state. Experimental results verifying the performances of the proposed square-rooting VFC are included. ©ICROS. - 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.1 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Amplitude modulation based on time-varying forced function of second-order oscillator circuit(2006-12-01); ; Koseeyaporn, PoolsakThis paper presents a novel technique of amplitude modulation which is based on a second-order oscillator circuit. By using the multi-time technique to analyze a second-order system for time-varying forced function, it is found that the system's forced response not only at an initial time but also at any arbitrary time is presented in term of the natural response's magnitude. It implies that amplitude of the natural response can directly be controlled by the forced response. For a condition that the forced response and the time-varying forced function is approximately identical, the resulted complete response of the second-order system therefore is amplitude modulation where the natural response and the time-varying forced function respectively represents sinusoidal carrier and information signals. To confirm the proposed technique, experimental results have been demonstrated which agree well with the given theoretical analysis. © 2006 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A simple circuit for sigma-delta /delta modulation(2005-12-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, New analytic solution of second-order oscillator using multi-time variables technique(2005-01-01); ; In this paper, a new analysis of sinusoidal oscillator amplitude controlled by forced response using the second order differential equation (ODE) is proposed. In general, the amplitude of the complete response is derived where forced response slope is normally assumed to be zero. The value of forced response only at initial time is thus employed to determine the amplitude. But if forced input is dynamic signal the amplitude of complete response gained by using such assumption is different from the experimental result. Thus, a new analysis of amplitude for a dynamic forced response is proposed in this paper. It is found that the forced response at any arbitrary time (not only at the initial time) is presented in a term of natural response magnitude. Magnitude of natural response is therefore directly controlled by forced response. To confirm the theoretical analysis, experimental results have been demonstrated and agreed well with the analysis results. © 2005 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, 7 Decade low frequency switched capacitor oscillator(2001-12-01); ; Maneechukate, ThongchaiIn this work a sine wave switched-capacitor (SC) oscillator based on feedback SC BPF oscillator is proposed. Advantage of this technique is high stability, constant amplitude at wide frequency range and suitable for amplitude control by output forced response technique. In addition, frequency tuning can be adjusted by clock control, which without effect to stability. The experimental results conforming the validity of the theory are also presented.2 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Triangular-to-cosine wave technique based on exponential approximation(2001-12-01); ; Maneechukate, ThongchaiA novel approach for triangular-to-cosine wave approximation is presented The cosine wave is generated by the method of squaring the triangular wave and the passing through the exponential amplifier circuits. This approach is based on the Taylor's series for sinusoidal function. The superior point of this method to the existing ones is the simple circuit realization and low distortion cosine wave output Besides that, the proposed circuit can generate the square, triangular wave. The section of square wave and triangular wave generating uses relaxation oscillator with feeding back in current mode that produce the triangular and square wave in the same circuit. Furthermore, the squaring and exponential amplifier circuit can be configured based on another principle such as translinear in current mode which can be developed to suit IC implementation.