• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.3
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• pp.217-223
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• 2007

This paper introduces an active sensing node using radio-frequency (RF) telemetry. This device has brought the traditional impedance-based structural health monitoring (SHM) technique to a new paradigm. The RF active sensing node consists of a miniaturized impedance measuring device (AD5933), a microcontroller (ATmega128L), and a radio frequency (RF) transmitter (XBee). A macro-fiber composite (MFC) patch interrogates a host structure by using a self-sensing technique of the miniaturized impedance measuring device. All the process including structural interrogation, data acquisition, signal processing, and damage diagnostic is being performed at the sensor location by the microcontroller. The RF transmitter is used to communicate the current status of the host structure. The feasibility of the proposed SHM strategy is verified through an experimental study inspecting loose bolts in a bolt-jointed aluminum structure.

• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.49-54
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• 2012

There is a possibility that electrical sparks may occur at discontinuities in metallic structures from distance of close to high power radio/radar transmitters. Voltage may be induced on these metallic structures by the radio-frequency transmitter. In this case, a person who comes into contact with these structure may be undergone a severe electrical shock. In this paper, assessment of the electrical shock and ignition hazards was investigated through experimental which are consisted radio transmitter and metallic loop-type structure in shield room. We measured that the induced voltage was highest at 61 MHz of transmission frequency, and confirmed the possibility of electric shock and explosion induced by a voltage or spark. But it is needed additional research where is opened site.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.242-247
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• 2009

In this paper, we investigate interference between short-range radiocommunication devices (SRDs) with frequency hopping spread spectrum (FHSS) and direct sequence spread spectrum (DSSS) methods when they are in the same frequency bands. In order to analyze interference from unwanted emission of SRD with DSSS to that of FHSS, Monte-Carlo (MC) simulation method is employed and interference probabilities are calculated. We simulate interference scenarios in accordance with several duty cycles and bandwidths. It is also assumed that the propagation model is free space The effect of distance between interfering transmitter and victim receiver is analyzed and bit error rate (BER) is simulated. From the interference analysis results, it is shown that duty cycle affects compatibility more than bandwidth does. Also, we can make sure of the separation distance which satisfies BER criterion when there are only one interfering transmitter and multiple interfering transmitters.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.4 s.316
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• pp.45-49
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• 2007

The isolation between transmitter and receiver has been a critical problem in a pulse-modulated RFID (Radio Frequency Identification) system where transmitter and receiver use the identical frequency. A method using a switch, a mixer, a BPF (band-pass filter), and an additional oscillator in the transmitter is proposed to improve the isolation between transmitter and receiver in an RFID system. The Proposed system up-converts the outgoing wave from a frequency different from the received signal and improves the isolation. The proposed method provided additional 20 dB improvement on the isolation.

• 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.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.12
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• pp.1240-1247
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• 2011

The localization of mobile robot in environment is a major concern in mobile robot navigation. So, many kinds of localization techniques have been researched for several years. Among them, the positioning system using ultrasound has received attention. Most of these ultrasonic positioning systems to synchronize the transmitters and receivers are used for RF (Radio Frequencies). However, due to the use of RF, the interference problems can not be avoided and the performance of radio frequencies directly affects the positioning performance. So we proposed the ultrasonic positioning system without synchronizing RF. The proposed system is based on existing USAT (Ultrasonic Satellite System) adopted infrastructure transmitting type, and consists of transmitter and receiver synchronizing modules instead of the radio frequency transmitters and receiver. The ultrasonic transmitters and receivers are synchronized individually by the transmitter and receiver synchronizing modules. In order to calculate the bias between the transmitter and receiver synchronizing modules, new positioning algorithm similar to GPS was proposed. The positioning performance of the improved USAT without synchronizing RF and the validity of the proposed positioning algorithm are verified and evaluated by experiments.

• Journal of Biomedical Engineering Research
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• v.3 no.2
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• pp.113-118
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• 1982

This paper presents a frequency modulated radio-telemetry, transmitter for monitoring and transmitting an exercise electrocardiogram (ECG) and respiration activity simultaneously on single carrier frequency in the standard FM broadcast band of 88-108 MHz. We have evaluated the performance of the FM telemetry transmitter which is proposed on the basis of an exercise ECG test in the treadmill.

• Journal of Advanced Navigation Technology
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• v.13 no.4
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• pp.475-481
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• 2009

This paper focuses the performance improvement of the train radio system (TRS) supporting the safe and accurate operations. The causes of troubles and the performance drift in TRS have been analyzed and measurement indexes have been selected. Frequency shifts of transmitters causing from train vibrations have been shown, and the improvement of frequency stability has been confirmed by use of vibration- proof pads.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.327-332
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• 2001

This paper proposes the system to describe the data transmission methods using the simply frequency transmission methods between a railway track and the train. This system can control the railway signals through the ABS or ATS system located in the train and stations, having the frequency about 433.92 MHz. It shows the advanced system to send a lot of data through the microprocessor installed in a transmitter and transmitter-receiver at the train and railway.

• Journal of Broadcast Engineering
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• v.12 no.3
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• pp.266-277
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• 2007

Recently, Transmitter Identification(TxID) technology has been issued as a technology of ATSC DTV. ATSC DTV networks are comprised of a plurality of transmitters, broadcasting the same signal sing one frequency network(SFN) connected to EDOCR. In this single frequency network, TxID technology has been recognized as a technology in the ATSC DTV system since it enables the broadcast authorities and classify multiple transmitters. However, conventional TxID uses extremely long spreading sequence to identifying transmitters, so it increases H/W complexity and registers. Thus, to solve those hardware problems, we propose an efficient signal processing technology using decimation algorithm. Furthermore, we certified the availability of the proposed algorithm via various simulations.