• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.1
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• pp.53-60
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• 2017

Most of present ultrasonic distance measurement technologies are based on the measurement of the TOF (: Time of Flight), the elapsed time during which the ultrasonic wave travels from its transmitter to receiver, to evaluate the distance the wave travels during that time. In this case, high distance measurement accuracy requires an accurate measurement of TOF. In order to acquire an accurate TOF, this paper proposes a method that produces the TOF by using a mathematical model of the received signal obtained from a mathematical model of ultrasonic transducer. The proposed method estimates the arrival time of the received signal retrospectively by comparing its wave form obtained after triggering point with its mathematical model in the sense of least-square. Experimental result shows that the effect of variation of triggering point can be decreased by implementing the proposed method.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.6
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• pp.59-68
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• 2017

Random process plays a major role in wireless communication system to analytically derive the probability distribution function of the various statistical distribution. In this paper, we derive the decreasing function of the exponential distribution under the given condition which is expressed as wireless channel condition. The probability distribution function of Gaussian, Laplacian, Rayleigh and Nakagami distribution are also derived. Extensive simulation results of these statistical distributions are provided to prove that random process has a significant role in the wireless communications. In addition, the Rayleigh and Rician channels show specific examples of visible distance communication and invisible distance channel environment. This paper is motivated by that we assume a block fading channel model, where the channel is constant during a transmission block and changes independently between consecutive transmission block, can achieve a better performance in high SNR regime with i.i.d channel. This algorithm for realizing these transforms can be applied to the Kronecker MIMO channel.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.7
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• pp.55-60
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• 2017

This paper is proposed on the transmit Method Finger-Printer Scanning of Mutual Capacitance Touch Screen Panel Using Differential Pulse for improving the security of computer information. This system is composed of differential pulse generator and Ring-Counter, also Supply voltage is 5V. this system generates the Pulse wave which is composed of In-Phase and Out of Phase at 1MHz while period of 2m/s. it is designed and be able to operate four channels. overall power consumption is approximately 78.08nW. This prototype is implemented in 0.25um CMOS Process and Chip area is $870um{\times}880um$.

• The Journal of the Acoustical Society of Korea
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• v.39 no.5
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• pp.435-440
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• 2020

Single-beam acoustic tweezers that are capable of manipulating micron-size particles in a non-contact manner have been used in many biological and biomedical applications. Current single-beam acoustic tweezer systems developed for in vitro experiments consist of a function generator and a power amplifier, thus the system is bulky and expensive. This configuration would not be suitable for in vivo and clinical applications. Thus, in this paper, we present a portable single-beam acoustic tweezer system and its performances of trapping and manipulating micron-size objects. The developed system consists of an Field Programmable Gate Array (FPGA) chip and two pulsers, and parameters such as center frequency and pulse duration were controlled by a Personal Computer (PC) via a USB (Universal Serial Bus) interface in real-time. It was shown that the system was capable of generating the transmitting pulse up to 20 MHz, and producing sufficient intensity to trap microparticles and cells. The performance of the system was evaluated by trapping and manipulating 40 ㎛ and 90 ㎛ in diameter polystyrene particles.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.12
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• pp.2628-2635
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• 2010

This paper analyzes the detection probability of FMCW (Frequency Modulated Continuous Wave) radar based on Doppler frequency and analog-digital converter bit and designs and implements signal processing part of FMCW radar. For performance evaluation, the FMCW radar system consists of a transmitted part and a received part and uses AWGN channel. The system model is verified through analysis and simulation. Frequency offset occurs in the received part caused by the mismatching between the received signal and the reference signal. In case of Doppler frequency less than about 38KHz, performance degradation of detection does not occur in FMCW radar with 75cm resolution The analog-digital converter needs at least 6 bit in order not to degrade the detection probability. And, we design and implement digital signal processing part based on DDS chip of digital transmitted signal generator for FMCW radar.

• The Journal of the Acoustical Society of Korea
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• v.41 no.4
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• pp.468-479
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• 2022

To detect targets with active sonar system in the underwater environments, the targets are localized by receiving the echoes of the transmitted sounds reflected from the targets. In this case, reverberation from the scatterers is also generated, which prevents detection of the target echo. To detect the target effectively, reverberation suppression techniques such as pre-whitening based on autoregressive model and principal component inversion have been studied, and recently a Non-negative Matrix Factorization (NMF)-based technique has been also devised. The NMF-based reverberation suppression technique shows improved performance compared to the conventional methods, but the geometry of the transducer and receiver and attenuation by distance have not been considered. In this paper, the performance is improved through preprocessing such as the directionality of the receiver, Doppler related thereto, and attenuation for distance, in the case of using a continuous wave with a bistatic sonar. In order to evaluate the performance of the proposed system, simulation with a reverberation model was performed. The results show that the detection probability performance improved by 10 % to 40 % at a low false alarm probability of 1 % relative to the conventional non-negative matrix factorization.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.6 s.121
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• pp.602-611
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• 2007

In this paper, the forward link of UHF RFID system is modeled in accordance with the EPCglobal class 1 generation 2(EPCglobal C1G2) UHF Radio-Frequency Identity protocol specification at $860{\sim}960MHz$. Based on the constructed model, characteristics on the forward link signal for the EPCglobal C1G2 RFID reader are simulated with the help of a MATLAB softwarein order to extract the design parameters of a transmit digital filter which meets the Korean RFID regulations. Herein, the forward link model is consisted of PIE source coding, transmit digital filter, modulation, local oscillator, and antenna. From the simulation results, the ranges of three design parameters(roll-off factor, cutoff frequency, the number of tabs) for transmit digital filter are obtained with different modulation techniques and the Tari(type a reference interval) values. Finally, DSB/SSB-ASK modulation technique can not satisfy the EPCglobal C1G2 specification when Tari equals to $6.25{\mu}sec$ in a multiple-reader environment. Consequently this paper can provide a guideline for design parameters of a RFID reader as well as the basic scheme of analyzing frequency interference problems in RFID environments, including multiple-reader and dense-reader environments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11A
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• pp.933-940
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• 2011

In this paper, Ka-band transceiver for road watch radar system is designed and fabricated. The transceiver for road watch radar system is composed of waveform generator, frequency generator. IF transceiver and RF up/down converter. The transceiver especially has 3 different waveform mode for target detection range. The transceiver had over 150 MHz bandwidth in Ka-band and 22 dBm output power. The receiver gain and noise figure was 30 dB and 4 dB respectively. The receive dynamic range was 65.28dB and amplitude imbalance and phase imbalance of I/Q channel was 0.3 dB and 1.8 degree respectively. The transceiver meets the required electrical performances through the individual tests.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.2
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• pp.179-188
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• 2015

Testing a radar system in real environment requires a lot of time and cost. Thus various target simulators are developed to evaluate the radar performance and its functions as well. In order to enhance the range resolution and the accuracy for tracking, recent radar system tends to use the wideband signal. In this paper, we summarize two target simulation methods - the direct sampling method with the digital memories and the beat frequency generation for the stretch processing - and suggest the condition to improve their performance for a wideband radar system.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.7 no.2
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• pp.86-91
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• 2014

This paper compare with SNR performance of coherent integration and non-coherent integration in radar system. This paper to prevent distortion of transmit signal and radar return in radar system is used to pulsed waveform. This paper to estimate target detection range and to compare with SNR performance used to coherent integration performed before the envelope detector and non-coherent integration processed after the envelope detector. Through simulation, SNR performance of coherent integration and non-coherent integration were comparatively analyzed. SNR performance of coherent integration is good proof higher than non-coherent integration.