• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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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.

• 한국광학회지
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• 제11권2호
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• pp.102-107
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• 2000

본 논문에서는 분산감소광섬유를 이용하여 정현파를 고차 솔리톤으로 진행시켜서 원하는 펄스 압축율을 얻은 후, 수반되는 pedestal을 반응시간이 빠른 포화 흡수제(Fast Saturable Absorber : FSA)로 제거하는 현실적인 방법을 제시하였다. 또한 DDF-MALM-DDF 구조를 제안하여 280 이상의 압축율과 변환 제한에 가까운 솔리톤 펄스열을 생성할 수 있도록 하였다. 그 결과로서 광시간분할다중시스템과 광샘플링 등에 이용될 수 있는, 10GHz의 반복율과 176 fs의 펄스폭을 가지는 고품질의 솔리톤 펄스열을 구현할 수 있는 시스템을 디자인하였다.

• 한국광학회지
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• 제5권1호
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• pp.37-44
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• 1994

유도 브릴루앙 반사광을 고출력 레이저에 응용할 때 요구되는 반사광 특성이 실험적으로 조사되었다. 집속 렌즈의 초점거리에 따른 유도 브릴루앙 반사광의 peak power 반사율과 위상공액도가 측정되었다. 또한 반사광 가운데 펄스압축된 부분만의 위상공액도가 측정되었다. 초점거리가 긴 경우(f=100cm) 반사광의 peak power가 입사광의 약 2배에 이르렀다. 이때 반사광 중에서 압축된 선두펄스만의 위상공액도는 약 90%로 다른 시간의 펄스보다 위상공액도가 우수했다. 공간적으로는 유도 브릴루앙 이득이 가장 큰 광축부분의 바사관이 최대의 펄스압축, peak power 반사율, 위상공액도를 보여서 유도 브릴루앙 산란을 응용할 때 가장 유용한 부분으로 확인되었다.

• 한국통신학회논문지
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• 제21권11호
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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.

• 전자공학회논문지B
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• 제28B권11호
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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.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권8호
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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.

• 한국광학회:학술대회논문집
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• 한국광학회 2002년도 제13회 정기총회 및 2002년도 동계학술발표회
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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.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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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

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
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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.

• 한국음향학회지
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• 제16권2호
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• pp.5-9
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• 1997

본 논문에서는 chirp 신호를 초음파 신호처리 시스템에 입력시킬 때 반사신호의 진폭을 최대로 얻기위한 chirp 신호의 대역폭을 결정하는 방법을 연구하였다. 초음파 신호처리 시스템에서 반사신호의 S/N 비는 초음파의 전파시에 발생하는 감쇠와 산란에 의하여 매우 낮게된다. Chirp 신호를 사용한 펄스 압축기술은 초음파 반사시스템의 S/N 비를 증가시킬 수 있는 방법중 하나이다. 시뮬레이션 및 실험결과, chirp 신호의 펄스폭이 넓을수록 출력이 증가하였고 동일한 펄스폭과 주어진 초음파시스템의 대역폭에 대한 최대출력은 chirp 신호의 대역폭이 초음파시스템의 대역폭 보다 1.15배 클 때 얻어짐을 확인하였다.