• ETRI Journal
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• 제27권3호
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• pp.267-272
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• 2005

The transmission performance of optical labeling based on a combined frequency shift keying/amplitude shift keying (FSK/ASK) format is studied by numerical simulation. The simulation demonstrates that the bit-error ratio (BER) characteristic of an ASK signal is limited by the extinction ratio, received optical power, and dispersion, simultaneously. However, an FSK signal is mainly limited by the extinction ratio (ER) and received optical power when the peak spectrum, which is used to detect the FSK signal, is relatively narrow.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 학술대회지
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• pp.883-884
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• 2004

High-speed IC for time-division multiplexing (TDM) optical transmission systems have been designed and fabricated by using InP heterojunction-bipolar-transistor (HBT) technology. The driver IC was developed for driving external modulators, featuring differential outputs and the operation speed up to 10 Gbps with an output voltage swing of 1.3 Vpp at each output which was the limit of the measurement. Because -3 dB frequency was 20GHz, this circuit will be operated up to 20Gbps. 1.3Vpp differential output was achieved by switching 50 mA into a 50 $\Omega$ load. The power dissipation of the driver IC was 1W using a single supply voltage of -3.5Y. Input md output return loss of the IC were better than 10 dB and 15 dB, respectively, from DC to 20GHz. The chip size of fabricated IC was $1.7{\Box}1.2 mm^{2}$.

• JSTS:Journal of Semiconductor Technology and Science
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• 제9권4호
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• pp.257-265
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• 2009

Recent progress in development of CMOS power amplifiers for mobile terminals is reviewed, focusing first on switching mode power amplifiers, which are used for transmitters with constant envelope modulation and polar transmitters. Then, various transmission line transformers are evaluated. Finally, linear power amplifiers, and linearization techniques, are discussed. Although CMOS devices are less linear than other devices, additional functions can be easily integrated with CMOS power amplifiersin the same IC. Therefore, CMOS power amplifiers are expected to have potential applications after various linearity and efficiency enhancement techniques are used.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권3호
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• pp.341-346
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• 2017

In this paper, we present a 60 GHz on-off keying (OOK) modulator in a 90 nm CMOS. The modulator employs a current-reuse technique and a switching modulation for low DC power dissipation, high on/off isolation, and high data rate. The measured gain of the modulator, on/off isolation, and output 1-dB compression point is 9.1 dB, 24.3 dB, and 5.1 dBm, respectively, at 60 GHz. The modulator consumes power consumption of 18 mW, and is capable of handling data rates of 8 Gb/s at bit error rate of less than $10^{-6}$ for $231^{-1}$ PRBS over a distance of 10-cm with an OOK receiver module.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 추계학술대회 논문집
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• pp.254-255
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• 2013

In this paper, four switches three-phase Z-source dynamic harmonic filter is proposed. It has many advantages, such as reduction of the cost, switching loss and smaller drive circuit. In order to reduction harmonics, new PWM modulation technique with a variable index has been suggested that in comparison with a fixed index type has more capability. The paper presents an application of direct current control(DCC) method in Z-source dynamic harmonic filter to reduce the harmonics generated by the non-linear load. The experimental results will verify the validity of the proposed method.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.911-914
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• 2004

This paper discusses on new two LCD technologies featured by the fast electro-optic response:one is polymer-stabilized FLCDs that exhibit V-shaped electro-optic (EO) switching called PSV-mode FLCDs with response time of 400 ${\mu}$ s; and the other is TN-mode LCDs that exhibit a frequency modulation response (called PM-TN LCDs)and a peculiar sensitivity to the high frequency component of driving voltage waveforms resulting in a short decay time constant of 5ms and an enhancement in the over-driving that yields short response time of 1ms between two gray levels.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.341-344
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• 1991

Current controlled pulse width modulation(PWM) for voltage source inverter(VSI) is one of the control method which controls the current directly so that we can perform vector control because it reduces the orders of differential equations of the induction machine. This paper propose a Fuzzy current controlled PWM which properly minimize a current ripple using Fuzzy theory in a constant switching frequency. This technique is applied to an electrical drive system with an induction machine(IM) by simulation. By comparison with the known classical method such as ramp comparison, hysteresis band method, our contribution shows the better performances.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 추계학술대회 논문집 학회본부
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• pp.309-313
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• 1990

Pulse width modulation using discontinuous conduction modes are applied to a full-bridge series resonant converter to regulate the output from no load to full load with low switching loss and a narrow range of frequency variation. Finally, a simple nonlinear discrete-time dynamic model for this proposed converter is derived using approximation. This discrete time model is linearized and a general input - output transfer function for the propelled converter is derived.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.501-503
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• 1996

In this paper, a novel control strategy for PWM current source converter and inverter is proposed, applying a multivariable state feedback control. The PWM converter controls line current to be sinusoidal and make input power factor unity. In addition, the modulation index control of dc link current is carried out, which produces lower loss of switching devices. Since the voltage control of inverter output filter capacitor is performed a decoupling of the d-q current of the induction motor is well retained. With the proposed algorithm, both high dynamic responses and satisfactory static performance can obtained.

• 전력전자학회논문지
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• 제3권2호
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• pp.118-124
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• 1998

This paper describes a relationship of a space vector PWM and a sinusoidal PWM and presents that the space vector PWM can produce linearly the output voltage to the unity MI(modulation index). At first, reference angles and holding angles are derived from expanding a Fourier series of the reference voltage waveform and then the angles are used for the inverter switching to linearize transfer characteristics of the inverter. In addition, the harmonic components of the output voltage are analyzed and on-line control is shown to be feasible by approximating in piecewise-linearization the reference and holding angles versus the MI. In V/f control of the induction motor, it is verified by the experiment that the motor current is changed smoothly for the variation of the inverter input voltage and the change of the reference voltage.