• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.1
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• pp.71-76
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• 2010

This paper is focused on implementing a real-time data acquisition system that checks power facility status by applying network based technology to Urban Transit substation power facilities and the results of its on-field tests. This system is composed of a sensor part, a measurement part, a transceiver part, a host computer, and a power source part. The system is designed to collect, save, analyze, and display the online state power facility AI (Analog Input). This system measures voltage and current from positive feeders and negative feeders where it is possible to check abnormalities of the substation‘s main power facilities. By monitoring abnormal data of the Urban Transit power facilities real-time and analyzing stored data, establishing procedures of optimized maintenance is possible.

• IEMEK Journal of Embedded Systems and Applications
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• v.2 no.1
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• pp.24-30
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• 2007

According to development of wireless communication technologies, we need not only high data rate but low data rate system of low power consumption. This low data rate system is utilized in the field of home automation, health care, sensoring and monitoring, etc. IEEE 802.15.4 LR-WPAN system is the best choice for realizing ubiquitous networking system. In this paper SoC Architecture for IEEE 802.15.4 Low Rate WPAN is designed. IEEE 802.15.4 Low Rate WPAN system serves the functions and realization of home area network. We propose the SoC architecture for 868/915MHz frequency band of IEEE 802.15.4 Low Rate WPAN system. The key issue is to design SoC architecture which provides the function of Low Rate WPAN system to meet the requirement of IEEE 802.15.4 standards.

• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.1
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• pp.11-19
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• 2020

IoT has been consistently used in various fields such as smart home, wearables, and healthcare. Since IoT devices are small terminals, relatively simple wireless communication protocols such as IEEE 802.15.4 and ISO 18000 series are used. In this paper, we designed the 802.15.4q 2.4 GHz TASK physical layer. Physical protocol data unit of TASK supports bit-level interleaving and shortened BCH encoding. It is spread by unique ternary sequences. There are four spreading factors to choose the data rate according to the communication channel environment. The TASK physical layer was designed using verilog-HDL and verified through the loop-back test of the transceiver. The designed TASK physical layer was implemented in a fpga and tested using MAXIM RFICs. The PER was about 0% at 10 dB SNR. It is expected to be used in small, low power IoT applications.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.73-74
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• 2006

In this paper, we designed, constructed and evaluated the system for the FTTH suited to a residence and apartment using CWDM-PON techniques. These systems have capacity to service at 100Mbps rate to 384 users in the same breath. Also, the services include the internet, CATV, IPTV and wireless LAN. In the case of wire network, the data could be transmitted by UTP cable and optical fiber and case of wireless one, the data transmitted using WLAN. The distance between the cental office and the user is 20km and the data rate is 100Mbps maximum. Of course, the optical network used just one fiber optical core. For the basic material, we obtained the characteristics of optical transceiver module, Mux/Demux and transmission qualities depends on the environment.

• Journal of Practical Engineering Education
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• v.13 no.2
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• pp.321-326
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• 2021

Wireless communication is a core technology constituting the Internet of Things (IoT), but there is no suitable educational equipment to learn various wireless communication technologies used in the Internet of Things through practice. This paper deals with the development of advanced education and training equipment that can perform various IoT wireless communication practices. It uses an Arduino mega board as a device to control various sensors. As wireless network technologies to send and receive the sensing date wirelessly, it makes use of RFID/NFC and Bluetooth among WPAN technologies, WiFi among WLAN technologies and LoRa and 2.4GHz wireless transceiver among WWAN technologies. In addition, GPS, infrared communication, I2C communication, and SPI communication are organized so that various IoT wireless communication technologies can be learned through practice. In addition, since the educational equipment developed in this paper is equipped with two devices, it is designed to perform transmission and reception experiments for wireless network technology within the equipment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.12
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• pp.1078-1085
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• 2011

In this paper, we analyze the relationship between energy per bit and the data rate with the variation of the system bandwidth. A existing power model is mathematical model to express power consumption of each device. In this paper, we have to investigate the system level energy model for the RF front-end of a wireless transceiver. Also, the effects of the signal bandwidth, PAR, date rate, modulation level, transmission distance, specific attenuation of frequency band, and the signal center frequency on the RF front-end energy consumption and system capacity are considered. Eventually, we analyze the relationship between energy per bit and the data rate with the variation of the system bandwidth so that we simulate the minimum energy per bit in the several Gbps data rate using Shannon capacity theory.

• Journal of IKEEE
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• v.16 no.1
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• pp.62-68
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• 2012

The planar microstrip antenna for the safety communication of life at sea is designed and manufactured to effectively receive the emergency wireless signal from the transmitter on the life vest. The proposed microstrip antenna in this paper is easy to make, light weight and cheap compared to other antennas because of printed antenna fabrication. To overcome the narrow bandwidth, large size and low gain characteristics of microstrip antenna, we use the IDMA(Identical Dual Patch Microstrip Antenna with Air-Gap) structure. The proposed antenna was fabricated with the use of 1.6mm FR4 and measured with the 28.7MHz(6.6%) of bandwidth and 3.04dBi of gain at the frequency of 426MHz. To validate the proposed antenna, we experimented the possible distance range at sea using the commercial UHF transceiver module and obtained over 5km distance for stable communication. This antenna can be widely applied to application of the UHF wireless mobile communication.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.2
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• pp.54-61
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• 1999

This paper describes the design of a 4-Mbps wireless infrared data transceiver chip. The receiver consits of the analog front-end, clock recovery and frame generator, and demodulator. The transmitter consists of the demodulator and LED driver. The versatile analog front- end consisting of multiple amplifiers makes it possible for the chip to be applied to various infrared environments by compensating DC and offset signal components. A 4PPM (pulse position modulation) scheme is used for data transfer in order to meet the IrDA standards. The chip was fabricated in a $0.8-{\mu}m$ 2-poly, 2-metal CMOS technology and dissipates 122mW for ${\pm}2.5V$ supply.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.8A
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• pp.1252-1258
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• 1999

This paper describes a COMS IF transceiver IC for 10-MHz bandwidth wireless local loops. It interfaces between the RF section and the digital MODEM section and performs the IF-to-baseband (Rx) and baseband-to-IF (Tx) frequency conversions. The chip incorporates variable gain amplifiers, phase-locked loops, low pass filters, analog-to-digital and digital-to-analog converters. It has been implemented in a 0.6 -${\mu}{\textrm}{m}$ 2-poly 3-metal CMOS process. The phase-locked loops include voltage-controlled oscillators, dividers, phase detectors, and charge pumps on chip. The only external complonents are the filter and the varactor-tuned LC tank circuit. The chip size is 4 mm $\times$ 4 mm and the total supply current is about 57 mA at 3.3 V.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.283-291
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• 2012

In this paper, a compact antenna is designed for the UWB lower half-band WVAN Gbps data-rate transceiver. The proposed antenna broadens the bandwidth less than -10 dB by placing the ring stubs and an open stub on the rectangular monopole above the partial ground and creating multiple resonant current paths. The designed antenna goes through the electromagnetic simulation and is fabricated and the implemented antenna has the characteristics of the return loss lower than -10 dB, the antenna gain greater than 5 dBi, and the efficiency over 80 % in the UWB lower half-band ranging from 3.197 GHz to 4.732 GHz. Therefore, it is thought that the proposed antenna is suitable for the size-reduced and excellently performing wireless communication transceiver.