• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.552-554
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• 1995

In long-haul high speed optical communications, the distance between a transmitter and a receiver depends on the amount of light coupled to a single mode optical fiber from the laser diode(LD) as well as the LD characteristic itself. And the transmitter module must have long lifetime. high reliability, and even simple structure. Such points have induced laser welding technique to be a first choice in opto-electronic module packaging because it can provide strong weld joint in a short time with very small coupling loss. In this paper, packaging considerations and characteristics for high speed LD modules are discussed. They include optical path design factors for larger aligning tolerance, and novel laser welding processes for component assembly. For low coupling loss after laser welding processes, the optical path for optimum coupling of a single mode optical fiber into the LD chip was designed with the GRIN lens system providing sufficiently large aligning tolerance both in the radial and axial directions. The measured sensitivity of the LD module was better than -33.7dBm(back to back) at a BER of $10^{-10}$ with a 2.5Gbps NRZ $2^{23}-1$ PRBS.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.259-262
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• 2003

In this paper, we designed and implemented digital wireless audio system with embedded RTOS using Bluetooth. Transmitter is consisted of a Settopbox, FIFO for interface block, Microprocessor(ARM7TDMI), UART driver and Bluetooth module. Receiver is consisted of a Microprocessor, AC-3 decoder, Bluetooth module and a Speaker with Amp. We programed Bluetooth protocal stack of HCI, L2CAP, and RFCOMM, so that Bluetooth module interacts with CPU.

• Journal of Korea Multimedia Society
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• v.18 no.5
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• pp.652-662
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• 2015

It is necessary to develop small, implantable bio-telemetry systems which can measure and transmit patients' bio-signals from internal body to external receiver. When measuring bio-signals, like electrical bio-signals, acoustic bio-signal measurement has also a big clinical usefulness. But, sound signal has larger frequency bandwidth than any other bio-signals. When considering these issues, a wireless telemetry system which has rapid data transmission rate proportional to wide frequency bandwidth is necessary to be developed. The bluetooth module is used to overcome the data rate limitation caused by the large frequency bandwidth. In this paper, a novel multimedia bluetooth biotelemetry system was developed which consists of transmitter module located in the body and receiver device located outside of the body. The transmitter consists of microphone, bluetooth, and wireless charging device. And the receiver consists of bluetooth and codec system. The sound inside the skin is captured by microphone and sent to receiver by bluetooth while charging. The wireless charging system constantly supplies the electric power to the system. To verify the performance of the developed system, an in vitro experiment has been performed. The results show that the proposed biotelemetry system has ability to acquire the sound signals under the skin.

• Journal of Biosystems Engineering
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• v.35 no.1
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• pp.21-30
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• 2010

This study was performed to develop an active tire pressure control system that can adjust tire pressure to the optimum level according to traveling and working condition of agricultural tractor. For the development of active tire pressure control system, pneumatic supplier, solenoid valve block including pneumatic supply line, infinite rotation type pneumatic supplier with rotary joint unit, tire pressure transceiver module and control algorithm were developed. Also, tire simulator was developed. Using this tire simulator, the feasibility of each part constructing actual system was tested by checking the performance. The average communication success ratio was 98.3% between tire pressure transmitter and receiver module according to the various tire rotational speed and data receipt position of receiver module. The communication performance of the developed transmitter and receiver module was very stable in any condition. The tire pressure control system was accomplished by using the proportional control algorithm in this study. Also tire pressure control performance of developed control system was analyzed by using the tire simulator. As a result of control performance analysis to the developed system, the developed control system took 307 seconds to inflate agricultural tractor's tire from 50 kPa to 180 kPa. In opposite case, it took 210 seconds. Also it was able to control the tire pressure accurately under ${\pm}0.9%$ (FS) in any condition.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.6
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• pp.1537-1544
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• 2012

In this paper, a new integration of linear mapping capability with 4-20mA current loop receiver. This module allow user to change instrument variable instantly. Configurations are easy to set by using console command through serial communication port. Break in current loop or faulty current transmitter are easily detect through indicator. The implementation of the module and the test results are discussed.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.6
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• pp.1513-1518
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• 2012

This paper is implemented media transmission system of VLC transmitter and receiver module using LED of White lighting that is based on PC module and to transmission technology for performance analysis. To realize LED visible light communication receiver is used 1~12 LED light-emitting device and transmitter is used a variable sensor. Developed initial distance of the tranceiver is more than 0~1m for LED VLC and the overall system transmission speed is achieved on variable having Visible light media transmission system. Composition to PC module with LED module and infrared sensor for performance analysis, predict and analyze the communication distance, check about the possibility of application methods. Measure each performance when the lens wearing and not wearing in order to increase the overall efficiency of the LED module, can know that increase efficiency of approximately 20%.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.6 no.2
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• pp.49-54
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• 2012

In this study, an E-learning system was developed for vocational rehabilitation training of intellectual disabilities. The developed system is available to have acquirement of knowledge through step by step learning and is configured to relearn through problem-solving and demonstration video. In addition, the learned information was composed to check the configuration which is correctly learning through rehearsal function. The device for rehearsal consists of a transmitter and the receiver. The transmitter is formed Pressure sensor, IR sensor for detecting client's work and Bluetooth module for wireless network. The receiver includes a Bluetooth module for wireless network and USB input terminal for communication with computer.

• Journal of Advanced Navigation Technology
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• v.13 no.1
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• pp.97-103
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• 2009

In this paper, the structure and detailed specifications of the HDR-WPAN physical layer have been analyzed and the block module of transmitter and receiver have been also designed, and analyzed the performance as well. In the process of transmitter design, it concentrated on all possibility of modulation of QPSK, DQPSK and 16/32/64QAM-TCM, which could be available for mode selection due to the transmission rate. In addition to the receiver module, DQPSK and TCM decoding algorithm is mainly concerned. After designing the transceiver MODEM using VHDL, we have programmed on the platform board and verified the functions of the MODEM. Some experimental results showed that it can be considered a possibility of data communication without error over SNR 22dB.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.2
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• pp.145-151
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• 2003

A global ultrasonic sensor system for self-localization of a mobile robot is proposed in this paper. The global ultrasonic sensor system consists of three or more ultrasonic transmitters fixed at some positions in the world coordinate and receivers in the moving coordinate of a mobile robot. In this global sensor system it is easy to get state vector of the mobile robot in the world coordinate from the distance information between each ultrasonic transmitter and receiver. An extended kalman filter algorithm is used to process the noisy ultrasonic signal and to estimate the state vector. In case of using several independent ultrasonic transmitters, it is necessary to avoid the cross talk among the ultrasonic waves and to synchronize between each ultrasonic transmitter and receiver. The small sized radio frequency modules are adopted to solve the cross talk and the synchronization problem Computer simulation and experiments are carried out to verify the effectiveness of the proposed ultrasonic sensor system.

• Journal of Digital Convergence
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• v.12 no.12
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• pp.257-264
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• 2014

Through MCU model, Radio Frequency communication is completed using universal asynchronous receiver and transmitter. The communicatin with PC and MCU is completed using RS-232 cable. At first interconnected communication with PC and MCU is necessary for RF communication because tha UART is based technique for RF communication. Program imbeded in microcontroller unit is ran during RF signal is transmitted to other RF module. Data connected with PC and MCU is transmitted between PC and MCU during PC and MCU is connected.