• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.6
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• pp.1602-1609
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• 1998

In this paper, the design and implementation of the novel RF front end circuit for CDMA based PCS phone is described. This novel scheme is realized by building the power amplifier module combined with duplexer. The dielectric filters which are parts of duplexer are broken up and relocated into the module. Electromagnetic analysis for via holes and coupling between narrow transmissio lines is icluded to design a circuit. The combined moule has been minimaturized to be as small as 1.5CC. It has satisfied IS-95 requirements for linearity performances of CDMA signal at 24-dBm output power as well as played apart as a duplexer. The operating current of about 95mA has been saved owing to both rearranging dielectric filters and limiting operating point to class-B by considering real working power range of CDMA phones.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12A
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• pp.1932-1938
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• 1999

In this paper, planar duplexer module combined with power amplifier is described. This new scheme is to enhance power efficiency as well as to minimize the size of RF circuit in CDMA phone. Each filter which was a part of duplexer, was realized with planar type and rearranged into the power amplifier module on the multilayer board. Each electrical specifications of existing power amplifier and duplexer were satisfied. Especially, ACPR performances measured at output power of 24dBm which is 2dB lower than that of a conventional one, meet IS-95 for a power amplifier of CDMA phone. Overall current about 80mA has been successfully saved as a result of new scheme. In addition, the module size has been reduced to be as small as 1.08CC.

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.265-268
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• 2006

This paper, suggest the Rrecord Management solution for unified RFID leader System based on WindowsCE. The unified RFID Reader System consider of RFID Module, GPS Module, CPU Module, WLAN(or CDMA) Module and DB into Local DB and Remote DB for of effective Record Management Systems.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.1 s.307
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• pp.7-12
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• 2006

In this paper we proposed a real-time remote monitoring system for interoperability between local area and wide area for wireless data communication. In local area, we used a miniaturized low-power wireless module and in wide area used CDMA Cellular System's Packet Data Service. The measurement results can be spread via Internet access in real-time

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.4
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• pp.523-533
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• 2000

In this paper, we present the hardware implementation of a smart antenna test-bed for a real -time performance analysis of the beam-forming algorithm operating in a wide-band CDMA environments of the WLL(Wireless Local Loop) standard. The test-bed introduced in this paper includes an external PC and signal generating module as well as the beam-forming module in order to perform, analyze, and evaluate the performance of the proposed smart antenna system. In the beam-forming module, the optimal weight vector is provided by the modified CGM algorithm. The computed weight vector is transferred back to the external PC for the performance analysis based on the off-line processing. From our analysis obtained in the hardware of the test-bed, it is concluded that the proposed smart antenna system for the WLL system is appropriate for enhancing the communication quality and capacity tremendously at the cell-site of the CDMA environment.

• Proceedings of the IEEK Conference
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• 2003.11b
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• pp.103-106
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• 2003

A Mobile Fingerprint Identification System is implemented in this paper. The proposed system contains a server system to register fingerprints and ID data, PDA with WLAN or CDMA module and fingerprint identification module.

• Journal of Advanced Navigation Technology
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• v.14 no.6
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• pp.824-830
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• 2010

PLC_Zigbee system, implemented in a previous study, uses ZigBee Node based on PLC (Power Line Communication). The weak point of the system is that the long distance powerline communication and PLC is impossible to use in the areas where the powerline is not installed. In this paper, we added CDMA (Code Division Multiple Access) module using a data transfer method of SMS (Short Message Service) and XBee of WSN (Wireless Sensor Network) module to the previous system, and got around the restriction of place and environment of PLC system through the interfacing of each communication media. We, thus, implemented a wide range of real monitoring system.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.1 s.6
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• pp.73-79
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• 2005

In this paper, a circuit for detecting a fine oscillation in an integrated PCS and W-CDMA receiver is presented. The advantages for this design are small size and flexible compatibility for system operation compared with the conventional method. The fine oscillation level can be detected by dB unit through selecting the receiver mode as PCS of 1.8 GHz range or W CDMA of 1.9 GHz range by a RF switch and monitoring the corresponding frequency band. Also, the circuit is designed to be flexible for other communication systems with the consideration of the required dynamic range of 75 dB.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.846-851
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• 2007

The contact and messenger wire is important parts in the electric power system of the railroad. There are so many measurement method like voltage, current, scratch of surface, and glow longer of length. In this paper suggest real time monitering system of messenger wire so called RTU (Remote Terminal Unit) and this system includes CDMA module to transfer real time or saved data of memory to the end user directly who is in the long distance. The hyper terminal program of windows shows the downloaded data from RTU through CDMA communication and this data can be transferred to excel sheet easily.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.389-393
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• 2003

This paper describes the design of enhanced TSSI RF Power Detector which has wide dynamic range using switch and Log amp. This Power Detector consists of low and high gain loops, and they adaptively switched by output DC voltage which is proportioned to input power level. Because Power Detector needs to separate the channel, so architecture is heterodyne system having 70MHz intermediate frequency. This proposed RF Power Detector is settle to the satisfaction of Closed loop power control system for W-CDMA optic repeater, and the obtained dynamic range cover the higher than 50dB.