• Journal of IKEEE
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• v.19 no.3
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• pp.335-341
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• 2015

Recently a demand for high precision absolute position transducer is increasing in order to control thickness in steel industry. LVDT (linear variable differential transformer) is widely used to measure the absolute position in the linearly moving cylinder under poor factory environment. In this paper we implement the three phase LVDT with a high resolution of one micron and L/D (LVDT to digital) converter. First we designed U, V, and W three phase signaling using FPGA. Second a pulse output algorithm is designed for position information with A and B phase waveforms. Finally the performance is compared with previous sensors. Experiments show that the linearity deviation error is 0.009788 [mm] and the average sinusoidal THD is 0.0751%, which means 2.2% and 33% more improved result than the previous sensors respectively.

• Journal of radiological science and technology
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• v.41 no.6
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• pp.603-610
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• 2018

This study examined the following: accuracy of the exposure conditions in the inverter device and three-phase device; output waveform over the exposure conditions; and average and standard deviation of the output waveform. After assessing whether the dose corresponding to the theoretical dose was presented, the following conclusions were obtained: 1. The accuracy of the tube voltage(kVp) and tube current(mA) exposure time(sec) was within the tolerable level prescribed in Korea's Safety Management Standards. In the error, Inverter device was large the tube voltage and exposure time, the three-phase device was large the tube current. 2. In terms of the output waveform of the exposure conditions and the average and standard deviation of the output waveform, the higher tube voltage and larger tube current resulted in greater standard deviation in pulsation. Moreover, the standard deviation of pulsation was shown to be greater in the inverter device than the three-phase device; there was also greater standard deviation in the inverter device considering the exposure time. 3. Regarding the exposure conditions over the output dose, all linearity showed the coefficient of variation which had an allowable limit of error within 0.05. Although the output dose ratio for the inverter device was 1.00~1.10 times no difference that of the three-phase device, there was almost no difference in dose ratio between the tube currents.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.7 no.4
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• pp.195-199
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• 2014

A bridge resistance deviation-to-period (BRD-to-P) converter is presented for interfacing resistive biosensors. It consists of a linear operational transconductance amplifier (OTA) and a current-controlled oscillator (CCO) formed by a current-tunable Schmitt trigger and an integrator. The free running period of the converter is 1.824 ms when the bridge offset resistance is $1k{\Omega}$. The conversion sensitivity of the converter amounts to $3.814ms/{\Omega}$ over the resistance deviation range of $0-1.2{\Omega}$. The linearity error of the conversion characteristic is less than ${\pm}0.004%$.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.125-126
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• 2008

A differential capacitance deviation-to-time converter for interfacing position sensor is presented. It consists of triaxial position sensor, six comparators, six current mirrors, and control logic. The prototype differential capacitance deviation-to-time interval converter has been simulated using Chartered $0.35-{\mu}m$ CMOS parameters. The simulation results show that the maximum conversion time of the converter is $350{\mu}s$ and the linearity error is less than ${\pm}0.00l5%$.

• Journal of IKEEE
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• v.19 no.4
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• pp.479-485
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• 2015

A resistance deviation-to-time interval converter based on dual-slope integration using second generation current conveyors (CCIIs) is designed for connecting resistive bridge sensors with a digital system. It consists of a differential integrator using CCIIs, a voltage comparator, and a digital control logic for controlling four analog switches. Experimental results exhibit that a conversion sensitivity amounts to $15.56{\mu}s/{\Omega}$ over the resistance deviation range of $0-200{\Omega}$ and its linearity error is less than ${\pm}0.02%$. Its temperature stability is less than $220ppm/^{\circ}C$ in the temperature range of $-25-85^{\circ}C$. Power dissipation of the converter is 60.2 mW.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.7 no.1
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• pp.40-44
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• 2014

A bridge resistance deviation-to-period (BRD-to-P) converter is presented for interfacing resistive biosensors. It consists of a linear operational transconductance amplifier (OTA) and a current-controlled oscillator (CCO) formed by a current-tunable Schmitt trigger and an integrator. The free running period of the converter is 1.824 ms when the bridge offset resistance is $1k{\Omega}$. The conversion sensitivity of the converter amounts to $3.814ms/{\Omega}$ over the resistance deviation range of $0-1.2{\Omega}$. The linearity error of the conversion characteristic is less than ${\pm}0.004%$.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.5
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• pp.72-78
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• 2006

The paper proposes reference model error feedback control scheme for motion control system with hard non-linear components as like saturation and dead-zone in plant input part. Additionally, the plant has the system uncertainty effected by plant model parameter deviation and disturbance. The control algorithm uses the reference model to apply additional feedback loop with the error between reference model output and actual output effected by disturbance and non-linear components. And the stability evaluation based on Popov stability and controller design method are formulated to be performed. The effectiveness of the proposed scheme is examined by simulations. The results are proven by reasonable performances following reference model responses with good disturbance rejection performance without over-tuning of controller.

• Journal of IKEEE
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• v.12 no.3
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• pp.167-171
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• 2008

A bridge resistance deviation-to-frequency (BRD-to-F) converter is presented for interfacing resistive sensor bridges. It consists of a linear operational transconductance amplifier (LOTA), a current-controlled oscillator (CCO). The prototype converter was simulated using commercially available discrete components. The result shows that the converter has a conversion sensitivity amounting to 16.90 kHz/${\Omega}$ and a linearity error less than ${\pm}$0.03 %.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.12
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• pp.70-78
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• 2000

A novel capacitance deviation-to-time interval converter based on ramp-integration is presented. It consists of two current mirrors, two schmitt triggers, and control digital circuits by the upper and lower sides, symmetrically. Total circuit has been with discrete components. The results show that the proposed converter has a linearity error of less than 1% at the time interval(pulse width) over a capacitance deviation from 295 pF to 375 pF. A capacitance deviation of 40pF and time interval of 0.2 ms was measured for sensor capacitance of 335 pF. Therefore, the high-resolution can be known by counting the fast and stable clock pulses gated into a counter for time interval. The application of a novel capacitance deviation-to time interval converter to a digital humidity controller is also presented. The presented circuit is insensitive to the capacitance difference in disregard of voltage source or temperature deviation. Besides the accuracy, it features the small MOS device count integrable onto a small chip area. The circuit is thus particularly suitable for the on-chip interface.

• Journal of IKEEE
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• v.23 no.2
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• pp.636-641
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• 2019

A simple resistance deviation-to-time period converter is proposed for interfacing resistive half-bridge sensors. It consists of two 2nd generation current conveyors(CCIIs). The proposed converter has simpler circuit configuration than the conventional converters using operational amplifiers or operational transconductance amplifiers(OTAs). The proposed converter was simulated using CCII implemented with AD844 IC chips. The simulation results show that the converter has a conversion sensitivity of $0.01934ms/{\Omega}$ over a range of $100-500{\Omega}$ resistance deviations and a linearity error less than ${\pm}0.002%$.