• Title/Summary/Keyword: pulse generator

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Design and Performance Analysis of UWB Modules for Borehole Radar System (시추공 레이더 시스템에 사용되는 UWB 모듈의 설계 및 성능 분석)

  • Cho, Jae-Hyoung;Kim, Sang-Wook;Kim, Se-Yun;Yook, Jong-Gwan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.11
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    • pp.1121-1129
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    • 2009
  • In this paper, the UWB(Ultra-Wide Band) modules such as a pulse generator and the LNA(Low-Noise Amplifier) with AGC(Auto Gain Control) are designed to construct a cross-borehole pulse radar system, of which performance is compared with the existing system. The budget and specification of the radar system are determined by calculating the total path loss of the underground medium including an empty cavity. The pulse generator is fabricated to have the repeatation frequency 40 kHz, the pulse width lower than 5 ns and the peak signal level +73 dBm. The UWB LNA is designed to have the noise figure 3.77 dB, the variable gain range 100 dB and the frequency range of 20 MHz to 200 MHz. Compared with the existing system in an actual test site, the implemented system renders it possible to detect the blind area due to the UWB LNA with low noise figure.

Characteristics of Unsteady Flows in a Semi-Induction System by a Variable Volume Helmholtz Resonator (가변 체적 헬름홀츠 공진기에 의한 유사 흡기 시스템의 비정상 유동특성)

  • Kang, K.E.;Kim, K.H.;Kang, H.Y.;Koh, D.K.
    • Journal of Power System Engineering
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    • v.13 no.6
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    • pp.57-62
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    • 2009
  • Unsteady flows in a semi-induction system was investigated to verify their characteristics. A semi-induction system was designed and made to verify the Sow characteristics in an intake system. To attain an intact wave of an intake pulse, a single semi-intake system was adopted as a test rig. The system consists of an intake pipe and a rotary valve as a pulse generator, and a variable volume Helmholtz resonator. The variable volume Helmholtz resonator was mounted in the intake pipe to enhance a breathing capacity and engine performance. The phase and amplitude of the pulsating flow in an unsteady flow system were found to affect the charging capacity significantly. The behavior of pressure wave, their phase and amplitude were investigated in various regions. Some of the results obtained from experiments were described.

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Acoustic Noise Reduction of Three-Phase SRM with Random Pulse Position PWM and Random Turn-on/off Angle Control

  • Khai, Nguyen Minh;Shin, Duck-Shick;Jung, Young-Gook;Lim, Young-Cheol
    • Proceedings of the KIEE Conference
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    • 2006.10d
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    • pp.139-142
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    • 2006
  • This paper describes a new method using random modulated strategies for switched reluctance machines. The proposed method is combined random turn-on, turn-off angle technique and random pulse width modulation technique. The purpose of this proposed method is to decrease harmonic spectrum, and thus reduce the emitted acoustical noise. A random generator is generated by linear congruential generator (LCG) using random pulse position (RPP) scheme. Simulation results show that the harmonic intensity of proposed method is better than that of conventional method.

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Propagation of Partial Discharge Pulse in High Voltage Motor Stator Windings (고압전동기 고정자 권선에서 부분방전 펄스의 전송)

  • 김희동
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.52 no.11
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    • pp.512-515
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    • 2003
  • This paper is to investigate how partial discharge pulse signal can flow in 6.6㎸ motor stator windings. Pulse propagation is experimentally analyzed in stator windings using a variety of frequency-domain techniques. The experiments were performed on two stator windings in the laboratory. Spectrum analyzer(9KHz to 3㎓) with tracking generator(100kHz to 3㎓) was used. Sweep time of the tracking generator was looms. The frequency spectrum of the response signal was detected by active FET probe(1㎓). The active FET probe has a flat amplitude response up to 1㎓ without high frequency attenuation. The stator winding acts as a low-pass filter below 600KHz, the high-frequency components being highly declined. The resonance peaks show about 1.1MHz and 2MHz in low frequency of No. 1 and No. 2 stator windings, respectively. This low-frequency range indicates that attenuation is low. The peaks of partial discharge magnitude show about 900MHz, 1.6MHz in No. 1 stator winding and about 800KHz, 1.4MHz in No. 2 stator winding.

Effect of the Electric Field on the Plant Protoplasts During Cell Fusion (세포융합시 전계하에서 식물세포가 받는 영향에 관한연구)

  • Lee, Sang-Hoon;Lee, Yon-Min;Cha, Hyeon-Cheol
    • Journal of Biomedical Engineering Research
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    • v.17 no.2
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    • pp.173-178
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    • 1996
  • The objective of this paper is to investigate the effect of AC field on the protoplast of plant cells. The results of investigation will be the basis for the development of etectric cell fusion device. For the experiment, we made the electrode and AC and DC pulse generator and observed the behavior of the protoplasts through the inverted microscope which is connected to the monitor and video recorder by the CCD camera. As a result, the numbers of rotating, moving and destructed protoplasts and viability of the protoplasts have close relation to the amplitude of AC field, while the rotation rate is closely related to the frequency of AC pulse.

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A 6.5 - 8.5 GHz CMOS UWB Transmitter Using Switched LC VCO

  • Eo, Yun Seong;Park, Myung Cheol;Ha, Min-Cheol
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.15 no.3
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    • pp.417-422
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    • 2015
  • A 6.5 - 8.5 GHz CMOS UWB transmitter is implemented using $0.18{\mu}m$ CMOS technology. The transmitter is mainly composed of switched LC VCO and digital pulse generator (DPG). Using RF switch and DPG, the uniform power and sidelobe rejection are achieved irrespective of the carrier frequency. The measured UWB carrier frequency range is 7 ~ 8 GHz and the pulse width is tunable from 1 to 2 ns. The measured energy efficiency per pulse is 2.1 % and the power consumption is 0.6 mW at 10 Mbps without the buffer amplifier. The chip core size is $0.72mm^2$.

Bidirectional pulse generator for removal of flue gas (배기가스 처리용 양방향 펄스 전원)

  • 박정호;고광철;강형부
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1997.11a
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    • pp.233-236
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    • 1997
  • An investigation has been made of the various plasma chemistry reactions that occur in the corona discharge of an electrostatic precipitator operating in a typical flue gas. As the results of investigation, sulphur dioxide is removed principally by reactions with OH radicals to produce sulphuric acid, while nitrogen oxides are removed principally by reduction via the N radical to molecular nitrogen. If electrostatic precipitator\ulcorner used for flue gases are operated with positive voltages instead of negative dc voltages, there are significant reductions in the emission of the undesirable gases SO$_2$, NO, and NO$_2$. Thus, in this paper we design the bidirectional pulse generator for removal of flue gas, where the pulse width is more than 50[nsec] and the maximum output voltage is more than 100[kVl.

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HIPIMS Arc-Free Reactive Deposition of Non-conductive Films Using the Applied Material ENDURA 200 mm Cluster Tool

  • Chistyakov, Roman
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.02a
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    • pp.96-97
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    • 2012
  • In nitride and oxide film deposition, sputtered metals react with nitrogen or oxygen gas in a vacuum chamber to form metal nitride or oxide films on a substrate. The physical properties of sputtered films (metals, oxides, and nitrides) are strongly influenced by magnetron plasma density during the deposition process. Typical target power densities on the magnetron during the deposition process are ~ (5-30) W/cm2, which gives a relatively low plasma density. The main challenge in reactive sputtering is the ability to generate a stable, arc free discharge at high plasma densities. Arcs occur due to formation of an insulating layer on the target surface caused by the re-deposition effect. One current method of generating an arc free discharge is to use the commercially available Pinnacle Plus+ Pulsed DC plasma generator manufactured by Advanced Energy Inc. This plasma generator uses a positive voltage pulse between negative pulses to attract electrons and discharge the target surface, thus preventing arc formation. However, this method can only generate low density plasma and therefore cannot allow full control of film properties. Also, after long runs ~ (1-3) hours, depends on duty cycle the stability of the reactive process is reduced due to increased probability of arc formation. Between 1995 and 1999, a new way of magnetron sputtering called HIPIMS (highly ionized pulse impulse magnetron sputtering) was developed. The main idea of this approach is to apply short ${\sim}(50-100){\mu}s$ high power pulses with a target power densities during the pulse between ~ (1-3) kW/cm2. These high power pulses generate high-density magnetron plasma that can significantly improve and control film properties. From the beginning, HIPIMS method has been applied to reactive sputtering processes for deposition of conductive and nonconductive films. However, commercially available HIPIMS plasma generators have not been able to create a stable, arc-free discharge in most reactive magnetron sputtering processes. HIPIMS plasma generators have been successfully used in reactive sputtering of nitrides for hard coating applications and for Al2O3 films. But until now there has been no HIPIMS data presented on reactive sputtering in cluster tools for semiconductors and MEMs applications. In this presentation, a new method of generating an arc free discharge for reactive HIPIMS using the new Cyprium plasma generator from Zpulser LLC will be introduced. Data (or evidence) will be presented showing that arc formation in reactive HIPIMS can be controlled without applying a positive voltage pulse between high power pulses. Arc-free reactive HIPIMS processes for sputtering AlN, TiO2, TiN and Si3N4 on the Applied Materials ENDURA 200 mm cluster tool will be presented. A direct comparison of the properties of films sputtered with the Advanced Energy Pinnacle Plus + plasma generator and the Zpulser Cyprium plasma generator will be presented.

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Pulsed Power Modulator based on IGBTs (IGBT 기반 고압 펄스전원장치)

  • Ryoo, H.J.
    • Proceedings of the KIPE Conference
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    • 2007.11a
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    • pp.43-46
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    • 2007
  • In this paper, a novel new pulse power generator based on IGBT stacks is proposed for pulse power application. Proposed scheme consists of series connected 9 power stages to generate maximum 60kV output pulse and one series resonant power inverter to charge DC capacitor voltage. Each power stages are configured as 8 series connected power cells and each power cell generates up to 850VDC pulse. Finally pulse output voltage is applied using total 72 series connected IGBTs. The synchronization of gating signal is important for series operation of IGBTs. For gating signal synchronization, full bridge inverter and pulse transformer generates on-off signals of IGBT gating and specially designed gate power circuit was used. Proposed scheme has lots of advantages such as long lifecyle, compact size, flat topped pulse forming, small weight, protection for arc, high efficiency and flexibility to generate various kinds of pulse output.

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