• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.3
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• pp.275-281
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• 2016

A novel bidirectional magnetic wireless communication system is proposed in this study. This system provides the communication capability between the source and load sides by high-frequency signal while wireless power is transferred. Contrary to the conventional wireless communication systems using complex IC circuit and active components, the proposed system is simply composed of passive components. It is practical and beneficial for environmental robustness, cost effectiveness, and simple implementation. The detailed static analysis of the proposed system for power and communication lines is established. The proposed system is experimentally verified, and results show that a 0.1 voltage gain for communication line is obtained while a 2.0 voltage gain for the power line is achieved. The proposed system is adequate for practical applications as it allows the inductive power transfer system to wirelessly and easily communicate between the source and load sides.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.8
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• pp.79-85
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• 2004

In this paper, the RF-ID system for ubiquitous tagging applications has been designed, fabricated and analysed. The RF-ID System consists of passive RF-ID Tag and Reader. The passive RF-ID tag consists of rectifier using zero-bias schottky diode which converts RF power into DC power, ID chip, ASK modulator using bipolar transistor and slot loop antenna. We suggest an ASK undulation method using a bipolar transistor to compensate the disadvantage of the conventional PIN diode, which needs large current Also, the slot loop antenna with wider bandwidth than that of the conventional patch antenna is suggested The RF-ID reader consist of patch array antenna, Tx/Rx part and ASK demodulator. We have designed the RF-ID System using EM and circuit simulation tools. According to the measured results, The power level of modulation signal at 1 m from passive RF-ID Tag is -46.76 dBm and frequency of it is 57.2 KHz. The transmitting power of RF-ID reader was 500 mW

• The Journal of the Acoustical Society of Korea
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• v.40 no.5
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• pp.428-438
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• 2021

For long-range communication in deep water, low carrier frequency is efficient due to a decrease in transmission loss. However, there is a limitation in that the data rate decreases due to a narrow bandwith. In order to increase the data rate in an environment with a limited bandwidth, it is necessary to design a higher-order modulation scheme. This paper analyzes the long-range communication data modulated by higher-order modulation schemes. The long-range communication experiment (23 km ~) was conducted in East Sea in October 2020. During the experiment, a vertical line array was utilized and communication sequences were modulated by Phase Shift Keying (PSK) and Quadrature Amplitude Modulation (QAM) schemes and transmitted by a towed source. In more detail, PSK modulation consists of quadrature PSK and 8PSK, QAM modulation consists of 8QAM and 16QAM. Time reversal processing is applied to mitigate inter-symbol interference by utilizing the correlation between received signals and channel impulse responses. All modulation schemes show successful results at 23 km range, demonstrating the feasibility of higher-order modulation in long-range communication.

• The Journal of the Korea Contents Association
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• v.9 no.2
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• pp.10-17
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• 2009

This paper analyze the effect of frequency offset for the IEEE 802.15.4b LR-WPAN(Low-Rate Wireless Personal Area Network) with 915MHz bandwidth noncoherent DSSS O-QPSK based receiver system, and presents a compensation method with addition of differential filter to the system for compensation of frequency offset problem. DSSS PSSS-ASK and DSSS O-QPSK modulation techniques are accepted within the regularization of IEEE 802.15.4b. These new method can obtain 250kbps transmission rate. The DSSS O-QPSK modulation method that is used in this paper has no BER variation below 40ppm(frequency offset 36.6kHz), but if the offset frequency become high above 40ppm, then the system cannot have stable receiving condition due to worse BER. To solve this problem, we present a more stabilized receiver system at maximum frequency offset ${\pm}80ppm$ using MDDF unti a correlator of DSSS O-QPSK modulator. Moreover computer simulation results will be presented to evaluate the performance of the proposed algorithm unde various AWGN and frequency offset environment.

• Transactions on Electrical and Electronic Materials
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• v.11 no.1
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• pp.20-23
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• 2010

The analog front end (AFE) of a radio frequency identification transponder using the ISO 14443 type A standard with a 100% amplitude shift keying (ASK) modulation is proposed in this paper and verified by circuit simulations and measurements. This AFE circuit, using a 13.56 MHz carrier frequency, consists of a rectifier, a modulator, a demodulator, a regulator, a power on reset, and a dynamically enabled digital phase locked loop (DPLL). The DPLL, with a charge pump enable circuit, was used to recover the clock of a 100% modulated ASK signal during the pause period. A high voltage lateral double diffused metal-oxide semiconductor transistor was used to protect the rectifier and the clock recovery circuit from high voltages. The proposed AFE was fabricated using the $0.18\;{\mu}m$ standard CMOS process, with an AFE core size of $350\;{\mu}m\;{\times}\;230\;{\mu}m$. The measurement results show that the DPLL, using a demodulator output signal, generates a constant 1.695 MHz clock during the pause period of the 100% ASK signal.

• The Journal of the Acoustical Society of Korea
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• v.35 no.1
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• pp.8-15
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• 2016

As a generalized form of the conventional Fourier transform, fractional Fourier transform (FrFT) can analyze a signal at intermediate domain between time and frequency domains with a transform order ${\alpha}$. Especially, FrFT has a number of advantages in the analysis of LFM (Linear Frequency Modulation) signals due to its robustness to noise. In this paper, we have proposed a new method to detect and estimate the distance of the target from the FrFT spectrum of the received echo signal. Experimental results have validated the proposed method, and shown that reliable target distance could be estimated in noise and reverberation environments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.1
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• pp.281-290
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• 1996

In this paper we suggest an OFDM star network based on carrier distribution and homodyne detection in which all optical carriers generated and stabilized in a specific node are distributed to each node. We studied ASK and PSK modulation schemes and calculated rspective SNRs and BERs for this network. We also discussed on the optical power requirement on the light sources for 200 Mb/s transmission speed. As a result, we found tht ASK and PSK respectively require 13 dBm and 10 dBm for 32 nodes and the nmber of nodes can be expanded to 73 with only 0 dBm of power and minimum insertion losses of components. The proposed network is more reliable than the conventional ones due to the centralized carrier maintenance andthe network is suitable for the adverse environment of the nodes.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.3
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• pp.232-242
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• 1997

In this paper, we have designed an active radio frequency identification system solving the problems of moving transponder which is identification range expanding and low battery consuming of transponder. Developed radio frequency identification system is a bidirectional data transmission system which is composed of decoder data transmission of 120 kHz and transponder data carrier of 60 kHz which is a subharmonic frequency response with ASK modulation. The experimental results, designed system operating at 9600 bps, show good performances with detecting the 40 km/h moving transponder up to the range of 2 and 15 ${mu}A$ low consuming current.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2000.11a
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• pp.115-122
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• 2000

Recently, a study on the Power Line Communication has been done by many companies and institutes due to its own merits that we can use the power line as a communication channel. But, there are serious problems about the harsh and unpredictable characteristics - noise, signal distortion and attenuation to be overcome in order that we commercialize the Power Line Communication. In this paper, we analyse the power line characteristics and apply the technology of PLC to control power of electric machinery by using ASK modulation.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.4
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• pp.889-897
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• 2001

Recently, a lot of studies on the power line communication(PLC) are being done by many companies and institutes due to its own merit which can use the power line spread widely as a communication channel. But, there are many serious problems about the harsh and unpredictable characteristics, or noise, signal distortion and attenuation to be overcome for commercialization. In this paper, the power line characteristics as the view point of communication channel are investigated and the technologies of PLC are proposed to control the power of electric machineries by using the combined method of ASK modulation and microprocessor technologies. Also experiments are carried out to ascertain performance in case of applying to electric lights control according to various distancea as an example.