• Journal of Satellite, Information and Communications
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• v.11 no.4
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• pp.15-20
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• 2016

In this paper, we developed the hardware GPS signal generator for generating a GPS L1 meaconing signal with Live GPS signal signals and analyzed the performance of meaconing signal generator thorough the experiment. Deception of the signal, such as a re-broadcast, it is an object of the user to provide false information so as not to receive location information and accurate time. The signal just rebroadcast has the features that can be easily deceive the receiver via a delay of no received signal to the signal processing through an antenna. In this paper, the hardware for generating a signal only these rebroadcast designed and manufactured, by re-sending the received Live GPS signals, to confirm the effect of the receiver. The maximum delay time is possible up to about 2.6msec, also, has been successfully tested to be moved to the position of re-broadcasting based on maturity antenna the position of the receiver through a spaced antenna.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.317-322
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• 2022

In general, life jackets are worn by people in critical situations on the water to rise to the surface without falling into water, and life jackets simply serve to prevent sinking, but do not actively help rescue disaster areas in critical situations early. In order to solve this problem, a device that automatically generates a distress signal in an emergency situation was developed. When the survivor is in hand for a while, the distress signal generator is automatically separated from the life jacket, allowing information such as location values and other information to be transmitted wirelessly and a rescue signal using LED light. As a result of the experiment, when submerged in water, the life jacket and the distress signal generator were automatically separated, and the result of wireless transmission of the coordinate value of the location received by the GPS was confirmed. By using this, the location of the distress or missing person can be identified, which can be quickly replaced in case of an emergency

• Journal of the Institute of Convergence Signal Processing
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• v.14 no.1
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• pp.39-44
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• 2013

In this paper digital phase-shifter for multi-arm spiral antennas was designed by using Hilbert transform. All frequency components in input signal are phase-shifted for 90 degree by Hilbert transform, and the transform is implemented by FIT and IFIT. Digital phase-shifter generates two signals with phase difference of 90 degree by using Hilbert transform from input signals sampled by analog-digital converter(ADC), and then the input signal is phase-shifted for a given phase by using two signals. Hilbert transform based on digital phase-shifter is designed by Xilinx System generator, and the effects of input noise, FIT point, sampling period, initial phase of input signal, and shifted phase are simulated and its results are compared with Matlab results.

• Journal of the Optical Society of Korea
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• v.19 no.3
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• pp.255-259
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• 2015

We have proposed and experimentally verified a pulse-width modulation (PWM) generator which directly generated a PWM signal in the optical domain. Output waveforms were clear at the repetition rate of 16 MHz; the duty cycle (DC) was from 14.7% to 72.1%; and the DC-control resolution was about 4.399%/dB. The PWM generator' operation principle is based on the injection-locking property of a single-mode Fabry-$P{\acute{e}}rot$ laser diode (SMFP-LD). The SMFP-LD, which has a self-locked mode wavelength at ${\lambda}_{PWM}$, was used to detect the power of the injection-locking signal (optical analog input). If the analog input power is high, the SMFP-LD is locked to the wavelength of the input signal ${\lambda}_a$ and there is no output after an optical bandpass filter (OBF). If the analog input power is low, the SMFP-LD is unlocked and there is output signal at ${\lambda}_{PWM}$ after the OBF. Thus, the SMFP-LD plus the OBF provide digital output for an analog input. The DC of the output PWM signal can be controlled by tuning the power of the analog input.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.83-85
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• 1996

Major cause of defects in steam generator tubes at nuclear power plant is the accumulation of magnetite and other byproducts of corrosion in the crevice gap between support plates and tubes. Since damaged tubes result in contamination of the secondary coolant by the radioactive primary coolant, they represent a safety hazard. Early detection of magnetite buildup is, therefore, imperative in order to take remedial measures such as chemical flushing. Although the eddy current testing is being used for the inspection of steam generator tubes, the interpretation of resulting signals is generally a difficult task. This paper uses the phase of sensor coil emf as the test signal to find a way of easier signal interpretation. Numerical study using FEM shows that the shape of resulting signal is good for identifying the relative position of the probe to the support plate, and for discreminating the different shapes and degrees of magnetite buildup in the crevice gap region.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.51 no.1
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• pp.52-54
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• 2002

This research presented in this paper focuses on a system development for checking stator's wedge of large generator in heavy industry. The system is composed of impactor, A/D converter and digital signal processing board. Also this paper proposes a method for detection of stator's insulating state using analysis algorithm. As developed impact system is acting, impact wave is generated real time and transferred data to microprocessor. Using communication program this signal move microprocessor to hard directory of note book with 1000 data/sec. The developed system and analysis program performed very well by real stator's wedge in large generator.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.5
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• pp.590-597
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• 2016

We designed the multiple scattering points generation system to simulate an actual situation of target signal for high range resolution radar system. This provides replicating the target signals and controlling the status of target signals for radar system. This is composed transmit antenna and multi target generator. Transmit antenna is waveguide array antenna and multi target generator has signal distribution module and control & power module. Multi target generator is able to provide the high isolation and variable output power. Moreover, in order to monitor all output signals of the multi target generator, the flows of signals are programed in control & power module. The performance is demonstrated using experimented results of high range resolution radar.

• Nuclear Engineering and Technology
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• v.46 no.6
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• pp.883-888
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• 2014

This work presents the influence of noise originating from the tube itself on the detectability and sizing accuracy for laboratory-induced outer diameter axial cracks in nuclear steam generator tubes. The variations of signal amplitude and phase angle of the same cracks were analyzed when increasing the signal-to-noise ratio of the tube itself from 9 to 18. It was experimentally verified that the detectability for small cracks was enhanced by increasing the signal-to-noise ratio. The phase angle also rotated to a value representing the actual position and depth of a crack when increasing the signal-to-noise ratio.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.2
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• pp.127-134
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• 2022

In this paper, a low-cost, flexible GPS simulator based on USRP is designed as a general-purpose software wireless front-end. The simulator consists of a software GPS signal generator and a USRP-based RF transmitter. The simulator supports various scenarios including specified reception time, quantization bit level, I/Q data types, IF frequency, sampling frequency, SNR, ionospheric delay and user dynamics. The generated GPS RF signal is verified using the spectrum analyzer and off-the-shelf GNSS receivers such as U-blox M8T. The experimental results shows that the difference between generated and real live signal is ignorable. It is expected that designed GPS simulator can be used to GNSS signal design, receiver design and signal processing algorithms such as anti-jamming.

• Journal of the Semiconductor & Display Technology
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• v.2 no.4
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• pp.1-7
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• 2003

In this paper, we design the pattern generator circuits using PLDs(Programmable Logic Devices). The pattern generator is the circuit which generates the test pattern signal for the inspection of logical defects of semiconductor products. The proposed circuits are designed by the PLD design tool(MAX+ II of ALTERA). Also the designed circuits are simulated for the verification of the designed ones. The simulation results have a good performance.