• 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.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.299-307
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• 2013

In this paper, design of UWB Antenna which propagate impulse by pulse fidelity and distortion equation was induced and applied. UWB Antenna which has directional characteristic in UWB band should have low radiation loss and impulse radiation distortion. As a result, the paper designed wide band impedance transformer and microstrip slotline transit region structured antenna feeder line. By using the fabricated UWB antenna, the radiation pattern was measured in the radio anechoic chamber. Pulse fidelity of impulse radiation show good results more than 93% within ${\pm}30^{\circ}$ beam width.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.6
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• pp.553-563
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• 2010

This paper presents a tapered slot-antenna(TSA) for optimal impulse-signal transmission in ultra-wide band(UWB). The proposed TSA provides radiates in end-fire direction, which meets an impulse-radio UWB(IR-UWB) system demands(e.g., low loss, thus less error throughout the UWB band). In order to minimize the pulse distortion, we used an wideband impedance transformer and a microstrip slotline. The pulse fidelity characteristics was evaluated with finite-difference time-domain(FDTD) analysis technique and pulse fidelity correlation equation. Approximately 93.89 % pulse fidelity was obtained between the two antennas in 0.5 m range. Additionally, derived chirp Z-transform algorithm enables us to utilize the zoom-in option on the pulse signal in few nano-seconds below. Thus, it is possible to analyze the pulse signal distortion, delay or dispersion characteristics.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.5
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• pp.103-115
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• 2012

In this paper, design and performance evaluation of Tapered Slot Antenna for IR-UWB which propagates impulse radio is performed. TSA which has directional characteristic in UWB band should have low radiation loss and minimized impulse radiation distortion. In order to achieve these objectives, the paper designed wide band Impedance transformer and microstrip-slotline transit region structured TSA feeder line. By using the fabricated TSA, the radiation pattern was measured in the radio anechoic chamber. Pulse fidelity and distortion equation was induced to evaluate time domain characteristics according to the impulse radiation. Pulse fidelity of Impulse radiation show favorable results more than 93% within ${\pm}30^{\circ}$ beam width.

• Journal of the Korean Institute of Telematics and Electronics
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• v.15 no.6
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• pp.66-78
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• 1978

An assembly package program is developed for a computerize4 operation of a drilling machine system utilizing a microprocessor. Different drilling instruction requires merely the input of different sets of input data. To make pulse motors to follow their input pulse trains with fidelity, an optimum start-stop rate matrix is proposed, whose elements are determined according to the pulse motor torque and the load inertia of the mechanical system composed of a workpiece and a worktable.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.159-168
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• 2012

In this paper, we designed the antipodal vivaldi antenna for IR-UWB systems application and evaluated IR-UWB antenna performance for the ultra wideband impulse signal transmission in the time- and frequency-domain. The designed antipodal vivaldi antenna was fabricated using FR-4 substrate which thickness 1.6 mm, dielectric constant ${\epsilon}_r=4.7$ and $tan{\delta}=0.002$. We measured the return loss, far filed radiation pattern at the anechoic chamber in the frequency-domain. We also performed the pulse fidelity analysis in the time-domain using nano-second impulse signal transmission and demonstrated the feasibility of ultra wideband signal stable transmission in the UWB band. The designed and fabricated antipodal vivaldi antenna could be emitting and receiving the IR-UWB signal while preserving low pulse distortion and good radiation pattern in time- and frequency-domain.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.5
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• pp.362-368
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• 2023

In this paper, we presented the characteristics of the impulse signal which is applicable to the ultra-wideband antennas. In general, the width of the impulse has around sub nano or pico seconds in the time domain, where it corresponds to the wideband in the frequency domain. We confirmed by experiment that the impulse has around 130ps of the pulse width and bandwidth of 4GHz when 10MHz of sine wave excited as an input pulse. The fidelity factor was calculated in the time domain and -10dB bandwidth in the frequency domain was investigated for resistively loaded dipole antennas with different resistance per unit length. The received impulse signal through the wideband antennas is confirmed in the time and frequency domains that received pulse is to be similar to the generated impulse. The fidelity and bandwidth of the quantity value are 0.98 and 3.4GHz, respectively.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.10a
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• pp.204-207
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• 2003

The present paper reports high-fidelity simulation of direct initiation processes of cylindrical detonation waves by concentrated energy deposition. The goal is to understand the underpinning mechanisms in failed or successful detonation initiation processes. We employed the Space-Time CESE method to solve the reacting flow equations, including realistic finite-rate chemistry model of the nine species and twenty-four reactions for H$_2$-O$_2$-Ar mixtures. Detailed results of sub-critical, critical. and supercritical initiation process are reported.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.170-172
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• 2005

The DSD(Direct Stream Digital) encoder, which is a standard for SACD(Super Audio Compact Disc) proposed by Sony and philips, use 1 bit representation with a sampling frequency of 2.8224 MHz (64 $\times$ 44.1 kHz). For multi-rate PCM (Pulse Code Modulation) input like as 48/96/192 kHz, a external sample-rate converter is necessary to the DSD encoder. This paper has been proposed a digital filter structure composed of sample-rate converter and interpolation filter for the DSD encoder with multi-rate (48/96/192 kHz) PCM input. without a external sample-rate converter.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.358-360
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• 2005

The DSD(Direct Stream Digital) encoder, which is a standard for SACD(Super Audio Compact Disc) proposed by Sony and philips, uses 1 bit representation with a sampling frequency of 2.8224MHz (64${\times}$44.1kHz). For multi-rate PCM (Pulse Code Modulation) input such as 8${\sim}$192kHz, a external sample-rate converter is necessary to the DSD encoder. This paper has been proposed a digital mter structure composed of sample-rate converter and interpolaton filter for the DSD encoder with multi-rate (8${\sim}$192kHz) PCM input, without a external sample-rate converter.