• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.115-116
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• 1998

Pulse echo techniques have been used for the conventional medical ultrasound imaging systems. However, their resolution is limited in the transmitted signal power. To overcome this limit, pulse compression method used in the radar systems was proposed. This system transmits a continuous coded signal and then compresses the received signal into the short and high resolution pulse by using correlator. The reflectors can be detected by cross-correlation between the transmitted signal and the received signal with the depth information. In this paper, we will present a comparative study of the performances of the most common sequences(pseudo-chirp, m-sequences, modified Golay code). The best result for improving resolution is obtained with the modified Golay Code.

• Korean Journal of Optics and Photonics
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• v.11 no.2
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• pp.102-107
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• 2000

We propose a new scheme for generating a pedestal-free, femtosecond soliton pulse train by utilizing quasI-adiabatic high order soliton pulse evolution in dispersion decreasing fiber in conjunction with the intermediate pedestal suppression stage. Compression factor over 280 was achieved from lOGHz sinusoidal input, to 176 is soliton pulse train. train.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.11
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• pp.3012-3023
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• 1996

In this paper, we analyze the compression of optical soliton which is obtained by proceeding the optical pulse in FSDD(Fiber with Slowly Decreasing Dispersion) using both NSE(Nonlinear Schrodinger Equation) and GNSE(General Nonlinear Schrodinger Equation) and compare the results. We replace the FSDD with a sequence of fibers having different dispersion values and pompre the results with those obtained in FSDD. It is found that the same results in peak value and FWHM(Full width Half Maximum) can be obtained by replacing FSDD with a sequence of fibers having proper length. We vary the shape of initial pulse which is the input of FSDD and suggest the condition to obtain higher compression rate.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.11
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• pp.866-875
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• 1991

In this paper, multi pulse excited-linear predictive coding (MPE-LPC), where the correlation eliminated residual signal is modeled by a few pules, is shown to be effective for the compression of electrocardiogram (ECG) data, and a more efficient scheme for a faithful reconstruction of ECG is proposed. The reconstruction charateristic of QRS's and P.T waves is improved using the adaptive pulse allocation (APA), and the compression ratio (CR) can be changed by controlling the mumber of modeling pulses. The performance of the proposed method was evaluated using 10 normal and 10 abnormal ECG data. The proposed method had a better performance than the variable threshold amplitude zone time epoch coding (AZTEC) algorithm and the scan-along polygonal approximation (SAPA) algorithm with the same CR. With the CR in kthe range of 8:1 to 14:1, we could compress ECG data efficiently.

• 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.

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.174-175
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• 2002

We generate short optical pulses of ∼ 6 picoseconds at 10 GHz by chirped pulse compression based on phase modulation and chirp compensation. In the suggested method, sinusoidally driven intensity and phase modulators generate chirped pulses which are subsequently suppressed by chirp compensation using a single mode fiber.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.443-446
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• 2005

This paper presents the results of the design and implementation of the airborne pulse doppler radar signal processor using high multi-DSP for the multi-function radar capability such as short-range, midium-range, and long-range depending on the mission of the vehicle. Particularly, the radar signal processor is developed using two DSP boards in parallel for the various radar signal processing algorithm. The key algorithms include LFM chirp waveform-based pulse compression, MTI clutter filter, MTD processor, adaptive CFAR, and clutter map. Especially airborne moving clutter Doppler spectrum compensation algorithm such as TACCAR is implemented for the multi-mode airborne radar system. The test results shows the good Doppler spectral separation for the clutter and the moving target in the flight test environment using helicopter

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.23-28
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• 2005

An airborne radar is an essential aviation electronic system of the helicopter to perform various missions in all-weather environments. This paper presents the results of the design and implementation of the airborne pulse doppler radar signal processor using high multi-DSP for the multi-function radar capability such as short-range, midium-range, and long-range depending on the mission of the vehicle. Particularly, the radar signal processor is developed using two DSP boards in parallel for the various radar signal processing algorithm. The key algorithms include LFM chirp waveform-based pulse compression, MTI clutter filter, MTD processor, adaptive CFAR, and clutter map. Especially airborne moving clutter Doppler spectrum compensation algorithm such as TACCAR is implemented for the multi-mode airborne radar system. The test results shows the good Doppler spectral separation for the clutter and the moving target in the flight test environment using helicopter.

• The Journal of the Acoustical Society of Korea
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• v.16 no.2
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• pp.5-9
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• 1997

In this paper, when we use the chirp signal as input signal of ultrasonic signal system the technique for determining the bandwidth of the chirp signal that maximizes the amplitude of the compressed ultrasonic echo signal has been studied. In ultrasonic signal processing systems, the signal-to-noise ratio of the echo signal can be too low due to damping and scattering of the ultrasonic wave during transmission. Method of pulse compression using chirp signal is a means to increase the signal-to-noise ratio in ultrasonic pulse-echo systems. Simulation and experimental results showed that the output signal of ultrasonic system was increased by pulse width of chirp signal and the optimum-bandwidth of the chirp signal was 1.15 times larger than the bandwidth of the ultrasonic system.