• Title/Summary/Keyword: compressed pulse

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The Study on the Optimal Transmission Efficiency Characteristics of Pulse Energy Using Magnetic Pulse Compressors (가포화 자기스위치 MPC를 적용한 저온 플라즈마의 펄스에너지 전송효율 특성)

  • 이유수;정종한;정현주;김문환;김희제
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.52 no.9
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    • pp.383-387
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    • 2003
  • In this paper, we have studied about optimal transmission efficiency characteristics of pulse energy in a coal plant for removing environmental polluted gas. The electrical efficiency of pulse power systems depends on impedance of the reactor. To obtain high efficiency, we used MPC(Magnetic pulse compressor) as the power switch and tested their characteristics as electrode length of the reactor and charging voltage of capacitor, As results, we obtained a compressed pulse such as pulse voltage of 10㎸, rising time 200ns and pulse width of 500ns. With increasing electrode length, the load impedance was decreased but the electrical efficiency was increased.

Pulse Sequence based MR Images for Compressed Sensing Algorithm Applications (펄스열을 이용한 MR 영상의 Compressed Sensing 알고리즘 적용)

  • Gho, Sung-Mi;Choi, Na-Rae;Kim, Dong-Hyun
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.46 no.5
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    • pp.1-7
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    • 2009
  • In recent years, compressed sensing (CS) algorithm has been studied in various research areas including medical imaging. To use the CS algorithm, the signal that is to be reconstructed needs to have the property of sparsity But, most medical images generally don't have this property. One method to overcome this problem is by using sparsifying transform. However, MR imaging, compared to other medical imaging modality, has the unique property that by using appropriate image acquisition pulse sequences, the image contrast can be modified. In this paper, we propose the possibility of applying the CS algorithm with non-sparsifying transform to the pulse sequence modified MR images and improve the reconstruction performance of the CS algorithm by using an appropriate sparsifying transform. We verified the proposed contents by computer simulation using Shepp-Logan phantom and in vivo data.

The Study on the Mutual Characteristics Between Transmitting Efficiency of Pulse Energy and Wall Plug Consumed Power of Non-Thermal Plasma (저온 플라즈마의 펄스에너지 전송효율과 Wall Plug 소비전력과의 상호 특성에 관한 연구)

  • Jeong, Jong-Han;Jeong, Hyeon-Ju;Kim, Hwi-Yeong;Jeong, Yong-Ho;Song, Geum-Yeong;Kim, Geun-Yong;Kim, Hui-Je
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.51 no.10
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    • pp.506-510
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    • 2002
  • In this paper, we study on the mutual characteristics between transmitting efficiency of pulse energy and wall plug consumed power of non-thermal Plasma for removing environmental pollutive gas of coal plant. To obtain high pulse energy of our system, we used MPC(magnetic pulse compressor) of power switch and tested their characteristics by adjusting electrode length of reactor and charging voltage in capacitor. As a result, we obtained consumed power of wall plug and a compressed pulse of voltage 110kV, rising time 500ns. Impedance of load on increasing electrode length was decreased, but electrical efficiency was increased. These results indicate we can control critical voltage of pulse corona and electrical efficiency of economic cost in power plant.

Analysis of Effects of Phase Noise in Radar System (위상잡음이 레이더 시스템에 미치는 영향 분석)

  • Park, Jinsung
    • Journal of the Korea Institute of Military Science and Technology
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    • v.16 no.3
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    • pp.373-381
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    • 2013
  • In this paper, the effects of phase noise on the radar system were analyzed in terms of 3 point of view. The impact(s) on the compressed pulse waveform, the FMICW(Frequency Modulated Interrupted Continuous Wave) radar performance and the receiver sensitivity were investigated. From the investigation, it was indicated that the phase noise over 10 kHz offset frequency makes the side lobe level of compressed pulse worse. Also it was founded that the FMICW radar performance, especially at the noise level of range profile, is related to the phase noise. Finally, the investigation showed that the phase noise at local oscillator affects the receiver sensitivity.

Peak Power Reflectivity and Phase Conjugation Fidelity in a Pulse Compression Process by Stimulated Brillouin Scattering (유도 브릴루앙 산란에 의한 펄스 압축 과정에서의 Peak Power 반사율과 위상공액도)

  • 조민식;최병일;남창희
    • Korean Journal of Optics and Photonics
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    • v.5 no.1
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    • pp.37-44
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    • 1994
  • The characteristics of stimulated Brillouin scattering wave for applications to high power laser was experimentally investigated. The peak power reflectivity and the phase conjugation fidelity of Stokes wave with respect to the focal length of lens were measured, and the phase conjugation fidelity for a compressed part of the Stokes wave was also investigated. For the long focal length of lens.(f=100 cm), the peak power of the Stokes wave amounts to about twice as high as that of incident wave. The phase conjugation fidelity for the compressed leading pulse is up to 90%, better than that for other temporal parts of the Stokes pulse. In spatial distribution, the Stokes pulse from the axial region has the largest SBS gain, and it has been ascertained as a best candidate to the application due to excellent pulse compression, peak power reflectivity, and good phase conjugation fidelity.

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Development of multi-repetitive Pulse Compression System for excimer laser excitation (엑사이머 레이저 여기용 고반복 펄스압축 시스템 개발에 관한 연구)

  • 전상영
    • Proceedings of the Optical Society of Korea Conference
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    • 1989.02a
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    • pp.36-38
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    • 1989
  • We have developed Magnetic Pulse Compression System to realize repetitive excimer laser excitation. The principle of this system is to use the large change in permiability owing to the nolinear characteristics of ferro-magnetic material (Metglas2605s-2 metal ribon). Prior to the laser operation, the MPC system was tested with a dummy load (5$\Omega$) and laser head. Laser head has a discharge volume of 1.0 (w) x 2.0 (h) x 20.0(1) cm. This MPC system compressed a 6.2us (FWHM), 80 A pulse into a 0.4us(FWHM), 1.3kA pulse.

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A Pulse Power Supply for Metal Vapor Lasers (금속 증기 레이저용 펄스 전원 장치)

  • Cha Byung Heon;Lee Heung Ho;Jin Jeong Tae
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.54 no.5
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    • pp.190-197
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    • 2005
  • A reliable and compact pulse power supply using a thyratron and a magnetic pulse compression (MPC) circuit was developed for a metal vapor laser. The life time of the pulse power supply is expected to be much longer than that of a conventional thyratron-discharge type pulse power supply. A thyratron generated a long pulse of its conduction pulse width 500 ns and then it was compressed to less than 80 ns of its output voltage rise time by a three stage MPC circuit. This pulse power supply was applied to a laser plasma tube of 30 mm inner diameter and 1.5 m discharge length. It was operated several hundreds hours without any troubles.

A Pulse Power Supply for a Metal Vapor Laser Using IGBTs (IGBT를 사용한 금속증기레이저용 펄스 전원)

  • 진정태;차병헌;김철중;이흥호
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.53 no.8
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    • pp.415-419
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    • 2004
  • A pulse power supply using IGBTs and MPC (magnetic pulse compression) circuit was developed for a metal vapor laser. The life time of the pulse power supply is expected to be much longer than that of a vacuum tube or thyratron type pulse power supply. A series-connected IGBT array generated a long pulse of its pulse width 2 ${\mu}\textrm{s}$ md then it was compressed to less than 100 ns by a three stage MPC circuit. This pulse power supply was applied to a laser plasma tube of 10 mm inner diameter and 0.5 m discharge length. and successfully operated.

Experimental Study of Second Harmonic Ultrasound imaging with a Weighted Chirp Signal (가중 쳐프 신호를 사용한 초음파 고조파 영상 기법의 실험적 고찰)

  • 김동열;이종철;송태경
    • Proceedings of the IEEK Conference
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    • 2001.06d
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    • pp.151-154
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    • 2001
  • In this Paper, a new harmonic imaging technique is proposed and evaluated experimentally. In the proposed method, a weighted chin signal with a hanning window is transmitted. The RF samples obtained on each array element are individually compressed by correlating with the reference signal defined as the 2nd harmonic (2f0) component of a transmitted chirp signal generated in a square-law system. The proposed method uses the compressed 2f0 component to form an image, for which the crosscorrelation term with f0 component should be suppressed below at least -60dB. After experiment, the 6dB pulse width and peak sidelobe level of the compressed 2f0 component were 0.7us and -60dB, respectively. This result shows that the proposed method can successfully eliminate the f0 component with a single transmit-receive event and therefore is more efficient than the conventional pulse inversion (PI) method in terms of frame rate. We also observed that the 2nd harmonic compont starts to decrease for source pressure higher than 210kPa in water, which implies that SNR of the 2nd harmonic imaging using short pulses cnanot be incresed beyond a certain limit.

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Optical pulse compression at 1.319$\mu\textrm{m}$ through fiber-grating pair and further compression using soliton effects (광섬유와 회절격자를 이용한 1.319$\mu\textrm{m}$파장 광펄스의 압축과 솔리톤 효과에 의한 재압축)

  • 이재승
    • Proceedings of the Optical Society of Korea Conference
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    • 1991.06a
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    • pp.102-108
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    • 1991
  • Utilizing self-phase modulation effects of a dispersion-shifted fiber and delay-line characteristics of two gratings, mode-locked 80 ps pulses at 1.319${\mu}{\textrm}{m}$ wavelength from a Nd: YAG laser are compressed down to 2.1 ps. These pulses are further compressed down to 340 fs using higher order soliton effects in a common single mode fiber.

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