• Journal of Korea Multimedia Society
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• v.10 no.4
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• pp.548-558
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• 2007

This paper presents a method of location sensing of mobile objects using RF devices. By analyzing signal strengths between a certain number of fixed RF devices and a moving RF device, we can recognize the location of a moving object in real time. Firstly, signal strength values between RF devices are gathered, and then the values are normalized and constructed as a model feature vector for specific location. A number of model patterns are acquired and registered for all of the location which we want to recognize. For location sensing, signal strength information for an arbitrary moving RF device is acquired and compared with model feature vectors registered previously. In this case, distance value is calculated and the moving RF device is classified as one of the known model patterns. Experimental results show that our methods have performed the location sensing successfully with 100% rate of recognition when the number of fixed RF devices is 10 or more than 12. In terms of cost and applicability, experimental results seem to be very encouraging.

• Journal of IKEEE
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• v.3 no.2 s.5
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• pp.186-195
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• 1999

In this paper, the RF-modules composed of front-end, frequency synthesizer, modulator/demodulator and power control multi channel WLL personal system for W-CDMA using 10 [MHz] RF channel bandwidth has been implemented and considered. The measured transmission power is 250 [mW] which is very close to the required value. The measured flatness of power at the final output stage is ${\pm}1.5[dB]$ over the required bandwidth of the receiver. In addition, it is found that the chip rate transmitting spread signal is set to 8.192 [MHz], the required rate. The frequencies of RF_LO signal and LO signal of the modulator and the demodulator measured by a frequency synthesizer are satisfied with design requirements. The operating range of the receiving strength signal indicator and AGC units shows 60 [dB] respectively. Also the measured phasor diagram and eye pattern for deciding the RF modules compatible with baseband digital signal processing part are shown good results.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.42-47
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• 2001

Analyzing the ECG signal, we can find heart disease, for example, arrhythmia and myocardial infarction, etc. Particularly, detecting arrhythmia is more important, because serious arrhythmia can take away the life from patients within ten minutes. In this paper, we would like to introduce the signal processing for ECG analysis and the device made for wireless communication of ECG data. In the signal processing, the wavelet transform decomposes the ECG signal into high and low frequency components using wavelet function. Recomposing the high frequency bands including QRS complex, we can detect QRS complex and eliminate the noise from the original ECG signal. To recognize the ECG signal pattern, we adopted the polynomial approximation partially and statistical method. The ECG signal is divided into small parts based on QRS complex, and then, each part is approximated to the polynomials. Comparing the approximated ECG pattern with the database, we can detect and classify the heart disease. The ECG detection device consists of amplifier, filters, A/D converter and RF module. After amplification and filtering, the ECG signal is fed through the A/D converter to be digitalized. The digital ECG data is transmitted to the personal computer through the RF transceiver module and serial port.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.291-293
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• 1997

A new quadrature RF coil is designed for Breast MR Imaging. Quadrature RF coils for MRI have been useful to improve the signal-to-noise ratio (SNR) by "$\sqrt{2}$" using two orthogonal RF coils in combination. A modified Breast Quadrature coil is designed. It is a modified type of the high-pass birdcage coil. To reduce the field distortion, by using current feeding, the field pattern is optimized to achieve a quadrature circularly-polarized field pattern. The coil has been implemented for receive-only mode, and tested by phantom imaging. The experimental results show the utility of the proposed RF coil.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1771-1774
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• 2005

Recently, RFID has become popular in the field of remote sensing applications. Location awareness is one of the most important keys to deploying RFID for advanced object tracking. Generally, multiple reference RF stations or additional sensors are used for the location sensing with RFID, but, particularly in indoor environments, spatial layout and cost problems limit the applicability of those approaches. In this paper, we propose a novel method for location sensing with active RFID systems not requiring the need for reference stations or additional sensors. The system triangulates the position of RF signal source using the signal pattern of the loop antenna connected to the power detector. The power detector consists of a signal strength detector and a signal analysis unit. The signal analysis unit indicates the signal strength and serial number using the signal from the strength detector, and provides the direction of the signal to the application target. We designed three different signal analysis units depending on the threshold type. The developed system can sense the direction to the transponder located over 10 m away within the maximum error of $5^{\circ}$. It falls within a reasonable range in our normal office environment.

• Journal of the Institute of Convergence Signal Processing
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• v.23 no.2
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• pp.91-96
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• 2022

At the current camera-based technology level, sensor-based basic life pattern recognition technology has to suffer inconvenience to obtain accurate data, and commercial band products are difficult to collect accurate data, and cannot take into account the motive, cause, and psychological effect of behavior. the current situation. In this paper, radar technology for life pattern recognition is a technology that measures the distance, speed, and angle with an object by transmitting a waveform designed to detect nearby people or objects in daily life and processing the reflected received signal. It was designed to supplement issues such as privacy protection in the existing image-based service by applying it. For the implementation of the proposed system, based on TI IWR1642 chip, RF chipset control for 60GHz band millimeter wave FMCW transmission/reception, module development for distance/speed/angle detection, and technology including signal processing software were implemented. It is expected that analysis of individual life patterns will be possible by calculating self-management and behavior sequences by extracting personalized life patterns through quantitative analysis of life patterns as meta-analysis of living information in security and safe guards application.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.10
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• pp.1197-1205
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• 2014

Recently signal transmission of ultra high-definition(4K-UHD) video system is transferred as uncompressed high speed data. However, this has a limit to compose the system because EMI between separate cables of high speed interface section and skew bring distortion of the video signal and jitter. In this paper we applied V-by-One HS interface technique to transfer uncompressed high speed data. We analyzed HSD(High Speed Differential) transmission line signal integrity. Also we applied RF transmission technique instead of UHD video pattern control interface PCB design. When we measured V-by-One HS video signal of designed 4K-UHD class signal generator, We found that the transmission performance has been signal standard.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.1
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• pp.36-42
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• 2014

In this paper, we propose receiver using ESPAR antenna for diversity gain. The proposed receiver receive signal by changing direction of beam pattern alternately in the OFDM symbol time period when DoA is estimated. In this way, the proposed receiver obtains diversity gain. The proposed receiver has single RF chain. If beam direction is changed alternately then it causes spectrum spread. And then, ICI occur because of spectrum spread. This interference can be equalized at the frequency domain equalizer such as ZF, MMSE and ML. In simulation, the proposed system receive signal using beam pattern of $60^{\circ}$ and beam pattern of $120^{\circ}$ alternately in OFDM symbol time period when it is assumed that DoA is $60^{\circ}$ and $120^{\circ}$. The performance results confirm that it is possible that the proposed receiver obtains diversity gain.

• Aerospace Engineering and Technology
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• v.8 no.1
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• pp.187-196
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• 2009

Synthetic Aperture Radar(SAR) satellite system for broad-area imaging has RF systems including SAR radiating a high power, data link system transmitting the acquired image data from the SAR, TC&R(Telemetry, Command, and Ranging) to communicate with a ground segment to control a satellite. Each system transmits RF signal having various frequencies and radiates a high power, RS(Radiated Susceptibility) specification should be verified at an electronic unit mounted in satellite. RF interference can be happened because of non-linearity of a RF system. Therefore, we manufactured a structure model installed antennas which have a similar pattern with a real antenna, the effect by RF interference is analyzed and verified.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.157.1-157
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• 2001

A new methodology is presented to diagnose faults in equipment plasma. This is accomplished by using neural networks as a pattern recognizer of radio frequency(rf) impedance match data. Using a realtime match monitor system, the match data were collected. The monitor system consisted mainly of a multifunction board and a signal flow diagram coded by Visual Designer. Plasma anomaly was effectively represented by electrical match positions. Twenty sets of fault-symptom patterns were experimentally simulated with experimental variations in process factors, which include rf source power, pressure, Ar and O$_2$ flow rates. As the inputs to neural networks, two means and standard deviations of positions were used ...