Riewruja, Vanchai
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Riewruja, Vanchai
Alternative Name
Riewruja, V.
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vanchai.ri@kmitl.ac.th
39 results
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Item type:Publication, Linear Variable Differential Transformer Signal Conditioning Circuit Based on Phase-Locked LoopThe purpose of this paper is to propose a novel technique for extracting the position signal from an inductive displacement transducer named a linear variable differential transformer (LVDT). In general, the movement of the LVDT core causes its primary inductance change in linear form. The primary winding of the LVDT is used as a time-dependent element for the triangular and square wave generator, which can be called self-oscillation, to generate frequency. The advantage of the proposed technique is that it can measure the displacement using the LVDT without an external oscillator. The change in primary inductance causes the frequency deviation generated by the oscillator. The deviated frequency is captured and converted into a voltage signal using the principle of the phase-locked loop. All the components used in this study are commercially available. The merits of this proposed technique are simple configuration, small size, and low cost. Moreover, the operating range of the LVDT can be extended without the limitation of the nonlinear transfer characteristic. The performance of the proposed technique is discussed in detail and confirmed by experimental implementation. Experimental results show that the maximum error from the proposed technique is about 0.42% and the operating range of the LVDT can be extended to more than 200%. It can be seen that the proposed technique is suitable for embedded measurement in small or micro robots. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Simple square-rooting circuit using OTAs(2008-08-28)A method to implement a square-rooting circuit is described. The proposed circuit employs operational transconductance amplifiers (OTAs) as the only active elements. The implementation technique is based on an electronically variable resistor formed by the OTA, where the magnitude of the resistance is controlled by the output current, to provide the square-rooting function. The proposed scheme can operate with both a voltage input and a current input signal. The purpose of the circuit is emphasised in terms of simple configuration, high accuracy and low cost. Experimental results showing the circuit performance are presented. © 2008 The Institution of Engineering and Technology. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Temperature Compensation for Transformer-type TransducerA novel technique to compensate the temperature effect of a transformer-type transducer is proposed in this paper. The effect of the ambient temperature on the transformer-type transducer is investigated from a primary-winding current. The advantage of the proposed technique is that the temperature effect is compensated without requiring a temperature sensor, making it suitable for applications in robotic and automation systems operated in harsh environments. The primary-winding current of the transducer is generated using a second-generation current conveyor (CCII). The excitation signal of the transformer-type transducer is driven by the CCII and the current flowing through the primary winding is transferred to an output signal of the CCII. The deviation of the primary-winding current due to the temperature effect is evaluated from the output signal of the CCII. The temperature effect on the transducer is manipulated by a closed-loop principle using a subtract-and-sum action instead of a traditional proportional-plusintegral action to eliminate the deviation of the primary-winding current. Therefore, the temperature effect on the transducer is compensated. A linear variable differential transformer (LVDT) is used to demonstrate the proposed technique, whose performance is discussed in detail and confirmed experimentally. All devices used in this experiment are commercially available. Experimental results show that the measured error of the output signal from the LVDT at 70 C can be reduced from 6.2% without temperature compensation to 0.06% by using the proposed technique, which has the advantages of a low cost, simple configuration, and high performance. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, CMOS-based integrable electronically tunable floating general impedance inverter(1997-01-01); Surawatpunya, CharrayAn integrable electronically tunable general impedance inverter (EGII), implemented by a MOS circuit design technique, is described. The driving point impedance of the EGII, that is inversely proportional to a given impedance, can be a positive or a negative value and can be electronically varied. The realization scheme employs proposed voltage-to-current transducers (VCTs) that are designed based on a linearizing technique, as basic circuit building blocks. The applications of the EGII as a gyrator, a general impedance converter and a floating capacitance multiplier are discussed. Experimental and simulation results that demonstrate the characteristics of the EGII are included. © 1997 Taylor and Francis Group, LLC. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Enhanced sinusoidal amplitude detector for fast response applications(2013-03-28); In this paper, an enhanced sinusoidal-amplitude detector suitable for fast response applications is proposed. Implementation method based on commercially available devices employs a novel control signal generator to improve operation speed of previously reported sinusoidal amplitude detector. The control signal generator used consists of a time-delay circuit, AND logic gate, and three comparators. The enhanced amplitude detector provides faster amplitude detection as well as smaller operation error for amplitude input changes. Experimental results verify a good agreement with theoretical expectation. © 2013 ICIC International. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Integrable CMOS-base realization of current conveyors(1991-01-01); Cheevasuvit, FusakSimple integrable circuits for implementing both positive and negative second generation current conveyors (CCII) are described. The realization method is suitable for fabrication using CMOS technology. Simulation and experimental results demonstrating the characteristics of the method are also included. © 1991 Taylor & Francis, Ltd. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Four-quadrant analogue multiplier using operational amplifier(2011-04-01); A method to realise a four-quadrant analogue multiplier using general-purpose operational amplifiers (opamps) as only the active elements is described in this article. The realisation method is based on the quarter-square technique, which utilises the inherent square-law characteristic of class AB output stage of the opamp. The multiplier can be achieved from the proposed structure with using either bipolar or complementary metal-oxide-semiconductor (CMOS) opamps. The operation principle of the proposed multiplier has been confirmed by PSPICE analogue simulation program. Simulation results reveal that the principle of proposed scheme provides an adequate performance for a fourquadrant analogue multiplier. Experimental implementations of the proposed multiplier using bipolar and CMOS opamps are performed to verify the circuit performances. Measured results of the experimental proposed schemes based on the use of bipolar and CMOS opamps with supply voltage ±2.4 V show the worst-case relative errors of 0.32% and 0.47%, and the total harmonic distortions of 0.47% and 0.98%, respectively. © 2011 Taylor & Francis. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A class AB CMOS square-rooting circuit(1998-01-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, OTA-based electronically tunable voltage-controlled resistance converter(1989-01-01) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A low-voltage wide-band CMOS precision full-wave rectifier(2002-06-01); Guntapong, RojanakornA simple integrable circuit for implementing a precision full-wave rectifier circuit in CMOS technology, which can be operated from a low-voltage power supply, is described. The realization method is based on the use of a MOS class AB configuration to improve the high frequency performance. The circuit exhibits a very sharp corner in the dc transfer characteristic. Simulation results showing the performance of the proposed circuit are also presented.