• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.12
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• pp.10-18
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• 1997

The parallel trabutary signals in the SDH-based transmission system have the frame phase skew due to uneven transmission delays in the data and the clock path. This phase skew must be eliminated prior to synchronously multiplexing process. A new twenty-four channel, 51.84Mb/s DFPA(Digital Frame Phase Aligner) has been designed and fabricated in 0.8.mu.m CMOS gate array. This unique device phase-aligns the skewed input signals with refernce frame synchronous signal and reference clok for subsequent synchronous multiplexing process. the performance of fabricated device is evaluated by the STM-16 transmission system and DS-3 meansurement set. The frame phase margin of +2/-3 bit periods has been demonstrated.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.5
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• pp.25-34
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• 1997

Relatively slow tuning speed of optical device causes the unwanted delay in high speed single-hop multiwavelength networks. To lessen the overhead, we present a channel access protocol with dynamjic message scheduling. Th eframe structure of proposed protocol adopts hybrid multiaccess scheme in which WDMA is used as a basic multiaccess technique and TDMA is used to provide subchannels within a wavelength band. This architecture has two merits : the network extention is not limited by available number of wavelengths, and the transmission delay caused by optical device tuning time can to minimize the number of tunings. It schedules messages that require same wavelength channels sequencely, so the total transmission delay is reduced by decreasement of wavelength changes. The performance of proposed protocol is evaluated through numerical analysis based on probability and queueing theory. The peformance of proposed protocol is evaluated through numerical analysis based on probability and queueing theory. The numeric results show that the peformance of proposed protocol is better than that of previous one.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.1
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• pp.84-93
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• 1998

Planar graded index optical waveguides have been formed by Ag$^{+}$ ion exchange in the BK7 optical glass. The experimental results of diffusion and modal characteristics of Ag$^{+}$-Na$^{+}$ exchanged BK7 glass waveguides are presented. Measurements of the mode indices have been measured. We found the relations between the process and device parameters such as the diffusion depth and the square root of the diffusion time, diffusion coefficient and diffusion temperature, and diffusion ion concentration and surface index change. A theoretical gaussian function refractive index profile matched best with the measured data for all the guided modes. The empirical relations between the process and the device parameters are derived and subsequently used to formulate a systematic procedure for fabricating singlemode and multimode waveguides.uides.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.1
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• pp.61-64
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• 1994

The NMOSFET with gate length of 0.1$\mu$m is fabricated by mix-and-match method. In this device, the electron beam lithography is used to form the gate layer, while other layers are formed by the stepper. The gate oxide is 7nm thick, and the device structure is normal LDD structure. The saturation Gm for gate length of 0.1$\mu$m is 246mS/mm. The subthreshold slope is 180mV/decade for 0.1$\mu$m gate length, but the slope is 80mV/decade for 0.3$\mu$m gate length.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.12
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• pp.59-64
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• 1996

InSb MIS devices prepared by remote PECVD SiO$_{2}$ were fabricated. The SiO$_{2}$ films on InSb were deposited at atemperature range of 67~190$^{\circ}$C. The effects of deposition temperature on the structural characteristics of the SiO$_{2}$ films evaluated Auger electron spectroscopy showed that atomic raito of silicon to oxygen was 0.5 and composition toms were distributed uniformaly throuout the oxide film. The transition region is about 100$\AA$ for SiO$_{2}$/InSb interface. The leakage current density at 1MV/cm and the breakdownelectric field of the MiS device using SiO$_{2}$ film deposited at 105$^{\circ}$C were about 22 nA/cm$^{2}$ and 3.5MV/cm, respectively. The interface-state density at mid-bandgap extracted from 1 MHz high frequency C-V measurement was about 2X10$^{11}$ cm$^{-2}$eV$^{-1}$.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.1
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• pp.100-106
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• 1999

A new IBC(Island Body Contact) structure is introduced to SOI CMOS VLSI for stabilizing the body potential of the MOSFET without the additional area consumption. The improvement of the body contact effect is achieved by reducing the body resistance and the area is saved as the bodies of the MOSFETs are connected together. Its property as VLSI device is confirmed through the device simulations and the measurement.

• Journal of the Korean Institute of Telematics and Electronics
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• v.10 no.2
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• pp.16-22
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• 1973

It is described about radiation monitor which can be used for rapidly checking the contamination caused by gamma and beta radiation. and for constantly monitoring such a probable hazardous area. In the circuits used in this device, a detailed analysis on the pulse amplifier and the design formulae of the discriminator circuit is presented. The device is all transistorized and the counting rates are audible through speaker besides being read by meter to the extent of maximum 10 k pps.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.1
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• pp.94-104
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• 1997

Most color imaging devices often exhibit color distortions due to the differences in realizable color gamuts and nonlinear characteristics of their components. In order to minimize color differences, it is desirable to apply color correction techniques. Th efirst step of color correction is to select the subset of the color coordinates representing the input color space. Th eselected subset serves as so called color samples to model the color distortion of a given color imaging device. The effectiveness of color correction is determined by the color sampels utilized in the modeling as well as the applied color correction technique. This paper presents a new selection method for color samples based on gentic algorithm. In the proposed method, structure of strings are designed so that the selected color samples fully represent the characteristics of color imaging device and consist of distinct color coordinates. To evaluate the performance of the selected color samples, they ar etuilized for three different color correction experiments. The experimentsal results are comapred with the crresponding results obtianed with the equally spaced color samples.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.4
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• pp.1-7
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• 1985

In this paper, a more improved threshold voltage model dependent on drain voltage and substrate bias for short - channel enhancement - mode IGFET is presented. Especially, compared with the several recently published models, the error is sufficiently reduced with the precise analysis on the correction factor for short-channel effect and the calculated values using this model are also agreed well with the experimental data about 1$\mu$m - channel length device.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.3
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• pp.389-396
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• 1986

A pulsed ultrasonic doppler flowmeter for mesurements of velocity profils in man is described. The device projects a beam of ultrasound in burst of 570 ns duration at 3.5 MHz. The back-scattered signals are processed to produce a signal oxrresponding to the mean velocity over a small region of the flowing stream. The observation range of 112mm is divided into 128 depth channels. The size of this sample volume determines the flowmeter sensitivity and accuracy. The device uses a quadrature detector to detect the direction of the moving target(hemoglobin). The main feature of the novel instrumnet is its simple hardware structure due to sequential signal processing.