• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.4
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• pp.181-187
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• 2003

This paper presents an 125MHz, 128-phase phase-locked loop using interpolation technique for digital timing recovery. To reduce the power consumption and chip area, phase interpolation was performed over only selected windows, instead of overall period. Four clocks were used for phase interpolation to avoid the output jitter increase due to the interpolation clock (clock used for phase interpolation) switching. Also, the output clock was fed back to finite-state machine (FSM) where the multiplexer selection signals are generated to eliminate the possible output glitches. The PLL implemented in a $0.25\mu\textrm{m}$ CMOS process and dissipates 80mW at 2.5V supply and occupies $0.84\textrm{mm}^2.

• International Journal of Precision Engineering and Manufacturing
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• v.2 no.4
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• pp.81-88
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• 2001

We present a new digital phase measuring method for heterodyne optical interferometry, which providers high measuring speed up to 6 m/s with a fine displacement resolution of 0.1 nanometer. The key idea is combining two distinctive digital phase measuring techniques with mutually complementary characteristics to earth other one is counting the Doppler shift frequency counting with 20 MHz beat frequency for high-velocity measurement and the other is the synchronous phase demodulation with 2.0 kHz beat frequency for extremely fine displacement resolution. The two techniques are operated in switching mode in accordance wish the object speed in a synchronized way. Experimental results prove that the proposed dual mode phase measuring scheme is realized with a set of relatively simple electronic circuits of beat frequency shifting, heterodyne phase detection. and low-pass filtering.

• KSBB Journal
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• v.15 no.6
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• pp.556-559
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• 2000

Cyclodextrin Glucanotransferase(EC 2.4.1.19 : 1,4-${\alpha}$-glucano) transferase, cyclizing; CGTase) can be separated and recovered in an aqueous two-phase system composed of poly(ethylene glycol)(PEG)/dextran and PEG/salt. In an aqueous two-phase system consisting of PEG 35000 (5%) and dextran T2000 (7%), all cell and debris were collected at the interphase. CGTase partitioned to the denser dextran phase at an yield of 83.4%. On the other hand, in an aqueous two-phase system consisting of PEG 35000 (10%) and sodium phosphate (15%), CGTase partitioned to the denser salt phase at an yield of 95.5%. In order to recover CGTase using an aqueous two-phase system, the PEG/salt system proved to be more efficient than the PEG/dextran system in terms of yield and cost.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.5
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• pp.273-278
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• 2004

This paper analyzed the phase noise characteristics of frequency-shifting module by figuring out the relationship between the phase noise components of 1st and 2nd local oscillator composing the frequency-shifting module and those of RF output signals shifted in frequency. Also, frequency-shifting module with the improvement of the phase noise performance was designed and implemented by means that the phase noise components of 1st local oscillator were cancelled in the output signal. Output signal has been affected by only phase noise of 2nd local oscillator, which had excellent phase noise performance than that of the 1st local oscillator.

• Current Optics and Photonics
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• v.2 no.5
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• pp.395-399
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• 2018

This article investigates the mechanism of electronic signal phase noise degradation induced by laser phase noise in optical links comprising optical resonators. Through theoretical derivation, we find that the phase noise of the output electronic signal has the same spectral shape of optical intensity noise as the output of the optical resonator. We propose that the optical resonator transfers laser phase noise to light intensity fluctuation and then the intensity fluctuation is converted to electric phase noise through AM-PM conversion mechanism in the photodiode. An optical link comprising a Fabry-Perot resonator was constructed to verify the proposed mechanism. The experimental results agree with our theoretical prediction verifying that the supposition is correct.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.4
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• pp.632-639
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• 1997

Relative density and microstructure of the pressureless sintered TiC-$TiB_2$ composite has been studied. The maximum sintered density was 95% and the critical amounts of sintering aids were 1 wt% Fe and 3 wt% Ni. It was found that TiC matrix phase inhibited effectively grain growth of the dispersed $TiB_2$ phase. The TEM investigation reveals that the Ni-rich precipitates were solidified from the liquid phase, confirmed by the presence of the waved and/or step phase boundaries. The precipitates also acts as the origin of the dislocation formation in the matrix phases.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.6
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• pp.110-116
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• 2015

In this paper, a compact low-loss reflector-type phase shifter with harmonic suppression using meander T-shaped branch-line coupler is suggested. The compact coupler for the phase shifter has a size of $22.2{\times}14.9mm^2$ while a conventional branch coupler has a size of $32.6{\times}27.8mm^2$. The phase shifter shows insertion losses of 0.19-0.28 dB at the center frequency of 2.1 GHz, and a measured maximum phase shift of $137^{\circ}$.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.2
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• pp.138-147
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• 2009

In this paper, improved direct torque control(DTC) system for five-phase squirrel-cage induction motor(IM) is proposed. Due to the additional degrees of freedom, five-phase 1M drives present unique characteristics. Also five-phase motor drives possess many other advantages compared with the traditional three-phase motor drive system, such as reducing an amplitude of torque pulsation and increasing the reliability. The DTC method is advantageous when it is applied to the five-phase IM, because the five-phase inverter provides 32 space vectors in comparison to 8 space voltage vectors into the three-phase inverter. However, five-phase motor has structural drawback of 3rd space-harmonics current component, it is necessary to controlled 3rd harmonic current. So to control 3rd harmonic current and enhance dynamic characteristics of five-phase squirrel-cage IM drive, modified DTC method should be demanded. The characteristics and dynamic performance of traditional five-phase DTC are analyzed and new DTC for five-phase IM is presented. A more precise flux and torque control algorithm for the drives can be suggested and explained For presenting the superior performance of the proposed direct torque control, experimental results are presented using a 32-[bit] fixed point TMS320F2812 digital signal processor with 2.2[kW] induction motor.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.757-765
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• 2007

OFDM system is an excellent high speed transmission method but it is seriously sensitive to the phase noise and IQ imbalance. Therefore, in this paper, we analyze the communication performance of the OFDM communication system with IQ imbalance and phase noise. Phase noise's variance can be calculated by integral calculus of phase noise power spectrum. From simulation results, it can be shown that the BER performances show different change according to the phase noise variance and IQ imbalance amount. When amplitude imbalance is ${\varepsilon}$=0.2; 0.3; 0.4 and phase imbalance is ${\phi}=10^0$, and distribution of phase noise is ${\sigma}^2=0.012$, BER is degraded by 2.88 dB, 3.61 dB, 4.09 dB in $10^{-5}$ in the respect of the SNR penalty.

• Journal of the Korean Ceramic Society
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• v.49 no.5
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• pp.469-474
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• 2012

The crystallinity and phase ratio of anatase to rutile in $TiO_2$ were estimated by x-ray diffraction (XRD) and x-ray absorption spectroscopy (XAS). Traditionally, the structural characterization of $TiO_2$ powders has been carried out by XRD techniques, which are comparatively easy in use and analysis. However, materials with amorphous phase, nano-sized or nano-structured crystallinities cannot be fully characterized by XRD because XRD analysis has a limit for abnormal contributions of the nano-crystal such as the surface contribution. From the comparison with the experimental and calculated Ti K-edge XAS spectra, we found the possibility of efficient estimation in the crystalinites and the phase ratio of anatase to rutile for nano-sized $TiO_2$ mixture.