• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.2
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• pp.132-139
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• 2002

This paper describes a supply voltage detector and SRAM write driver circuit which dissipates small power. The supply voltage detector generates high signal when supply voltage is higher than reference voltage, but low signal when supply voltage is lower than reference voltage. The write driver utilizes two same-sized drivers to reduce operating current in the write cycle. In the case of lower supply voltage comparing to Vcc, both drivers are active the same as conventional write driver, while in the case of high Vcc only one of two drivers are active so as to deliver the half of the current. As a result of simulation using 0.6${\mu}{\textrm}{m}$ 3.3v/5v, CMOS model parameter, the proposed SRAM scheme shows a 22.6% power reduction and 12.7% PDP reduction at Vcc=3.3V, compared to the conventional one.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.3
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• pp.342-348
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• 2015

This paper presents a new motion detector that has a bubble-layer detection zone using a pulsed-mode oscillator and delay line. The proposed motion detector controls the bubble-layer detection zone with pulse width of transmitted signals and creates IF signals only by reflected signals from the target within the detection zone whose position is determined by time delay of the delay line. The fabricated motion detector uses the pulsed-mode voltage controlled oscillator as a signal source which has a center frequency of 8 GHz, pulse width of 2 nsec and pulse period of 30 nsec. It successfully makes the bubble-layer detection zones at 1 m, 3 m and 5 m distant from itself using two delay lines with 7 nsec and 12 nsec delay, and is also demonstrated to detect the target within the detection zones.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.339-344
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• 2017

A novel structure of phase locked loop (PLL) which has small size and fast locking time with Early-late detector, Duty-rate modulator, and Lock status indicator (LSI) is proposed in this paper. The area of loop filter usually occupying the larger portion of the chip is minimized using a single small capacitor. While the conventional PLL with a single capacitor loop filter cannot work stably, the proposed PLL with two charge pumps works stably because the output voltage waveform of the proposed a single capacitor loop filter is the same as the output voltage waveform of the conventional 2nd-order loop filter. The two charge pumps are controlled by the Early-late detector which detects early-late status of UP and DN signals, and Duty-rate modulator which generates a steady duty-rate signal. Fast locking time is achieved using LSI. It has been simulated and proved by HSPICE in a CMOS $0.18{\mu}m$ 1.8V process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05b
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• pp.39-42
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• 2002

There is a renewed interest in the application of photoconductors especially Cd(Zn)Te to x-ray imaging. In this paper, We investigate effects on x-ray detection characteristic of Zn dopped CdTe detector. Cd(Zn)Te film was fabricated by vacuum thermal evaporation method and then investigate physical analysis using EPMA and XRD. We investigated the leakage current and X-ray photosensitivity as applied voltage about fabricated Cd(Zn)Te film. Experimental results showed that the increase of Zn dopped concentration in $Cd_{1-x}Zn_{x}Te$ detector reduced a leakage current and improved a signal to noise ratio significantly.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04c
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• pp.1-5
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• 2008

In this paper, we proposed that when combustible burn with ultraviolet radiation, introduce fire detector with sensor of private-use detectable light energy as ultraviolet in energy of electromagnetic-wave type radiate from flame. This research using ultraviolet flame sensor is pyro-electric ultraviolet sensor based black body radiation theory. To have high sensibility and to gain proper output voltage, it has high responsive performance. This research introduced UV flame detector and proposed method of false alarm reduced to resemble fire. the result proposed the prevention and extinction of fire technique degree, certificated operation of detector.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.783-788
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• 2005

Detection of small leakage current is the most important technique in arrester diagnosis. Various types of leakage current detector have been commercialized, but they are not available for the railway arresters including voltage harmonics, and do not furnish enough information needed for arrester diagnosis. This paper describes the development of a leakage current detector which is suitable for the railway arresters. The detector is consisted of a sensor unit with amplifier, an optical linker and main analyzer. Frequency bandwidth and measuring range of the detector is 9[Hz]$\~$850[Hz] and 50[uA]$\~$5[mA], respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05a
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• pp.28-31
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• 2004

A Quadrature phase detector for high-speed delay-locked loop is introduced. The proposed Quadrature phase detector is composed of two nor gates and it determines if the phase difference of two input clocks is 90 degrees or not. The delay locked loop circuit including the Quadrature phase detector is fabricated in a 0.18 urn standard CMOS process and it operates at 5 ㎓ frequency. The phase error of the delay-locked loop is maximum 2 degrees and the circuits are robust with voltage, temperature variations.

• 전기의세계
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• v.22 no.1
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• pp.35-41
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• 1973

An automatic point traffic control method is recommended for more idealistic traffic flow over coarse road netowrks. The automatic control apparatus recommended, consists of a transceiver, amplifier, digital-to-analog converter, signal light controller for emergency and steady state, and digital counter as monitor. The transmitter sends a signal to the target vy means of Microwave-FM-CW and a diode detector picks up the echo signal. Thus the operation of the entire system will be carried out through an open loop state. Some factors necessary for an ideal detector system are rapid response, longevity and stability. An analytical method of the Doppler effect substitutes the conventional frequency deviation into the amplitude of detector output. The changing rate of amplitude is proportional to the voltage of the detector output. Some induced formula from Maxwell's radiation field theory ensures this new method, and, new method, and proves the fact with an experimental data presentation. Stability depends upon Klystron as an oscillator and a diode as a detector. the transceiver installation affects on the response and sensitivity of the system. In accordance with the detector output, several targets are easily classified by amplitudes on the scope. The traffic flow, i.e., target movement which is analyzed by the amplitude method, is shown through the scope and indicates it on the digital counter. The best efficiency for the amplitude analysis can be attained through use of an antenna having the highest sensitivity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.8-11
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• 2003

We propose that when combustible burn with contain carbon, introduce fire detector with sensor of private-use detectable light energy as infrared and ultraviolet in energy of electromagnetic-wave type radiate from flame, method for correct discrimination to resemble fire produce false alarm of detector such as sun light, hot object radiation, are welding. This research using infrared sensor is pyroelectric infrared sensor based black body radiation theory. Ultraviolet sensor is uv Tron using gas multiplication effect to current discharge and photoelectric effect of metal. To have high sensibility and to gain proper output voltage, it has high responsive performance. This research introduced UV/IR compound type flame detector and proposed method of false alarm reduced to resemble fire. The result propres the prevention and extinction of fire technique degree, certificated operation of detector.

• Fire Science and Engineering
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• v.24 no.1
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• pp.111-115
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• 2010

For the development of fire detector equipments that was fused independent type of fire detector and a wireless communication function, this paper adopted a signal processing method of an independent formation fire sensor by a ZigBee communication method, and it was designed that the combinations of fire detector and wireless communications network were enabled. When a fire occurred, output voltage of a fire detector was 0.4 V, the movement pulse width was $600{\mu}s$, and that was confirmed by an experiment. When it has lookout state, LED worked by 30 s cycle and working current is 0.12 mA. When a fire occurred, LED worked by 0.5 s cycle and working current was 7 mA, and through this experiment of power source, Chamber tester, smoke tester,IRED, LED lighting, the propriety of the method that we showed in this paper confirmed.