• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.88-91
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• 2010

This paper describes a design of fast Fourier transform(FFT) processor for EEG(electroencephalogram) signal analysis for health care services. Hamming window function with 1/2 overlapping is adopted to perform short-time FFT(ST-FFT) of a long period EEG signal occurred in real-time. In order to analyze efficiently EEG signals which have frequency characteristics in the range of 0 Hz to 100 Hz, a 256-point FFT processor based on single-memory bank architecture and radix-4 algorithm is designed. The designed FFT processor has high accuracy with arithmetic error less than 3%.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.11
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• pp.2548-2554
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• 2010

This paper describes a design of fast Fourier transform(FFT) processor for EEG(electroencephalogram) signal analysis for health care services. Hamming window function with 1/2 overlapping is adopted to perform short-time FFT(ST-FFT) of a long period EEG signal occurred in real-time. In order to analyze efficiently EEG signals which have frequency characteristics in the range of 0 Hz to 100 Hz, a 256-point FFT processor is designed, which is based on a single-memory bank architecture and the radix-4 algorithm. The designed FFT processor has been verified by FPGA implementation, and has high accuracy with arithmetic error less than 2%.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.12
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• pp.107-112
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• 2021

The usage of electric-powered components consisting of several electrical and mechanical parts is continuously increasing in automobiles. Therefore, continuous assessment of the reliability and quality of these electric-powered parts is crucial. In this study, a noise and vibration measurement system for testing and evaluating the different electric-powered parts of automobiles was designed. Further, an FFT analysis was performed on some electric-powered steering assembly test equipment. In the FFT analysis of the noise and vibration signals for each essential fault part, the vibration FFT analysis was significantly compared with the noise analysis. The results showed that the vibration FFT analysis was more effective in determining the reliability and quality of the electric-powered parts.

• Speech Sciences
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• v.10 no.2
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• pp.57-64
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• 2003

The cepstrum coefficients are the most popular feature for speech recognition or speaker recognition. The cepstrum coefficients are also used for speech synthesis and speech coding but has major drawback of long processing time. In this paper, we proposed a new method that can reduce the processing time of FFT cepstrum analysis. We use the normal ordered inputs for FFT function and the bit-reversed inputs for IFFT function. Therefore we can omit the bit-reversing process and reduce the processing time of FFT ceptrum analysis.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1384-1387
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• 1996

SCPI(Standard Commands for Programmable Instrument) is a standard command sets designed for controlling various types of instruments. In order to control FFT(Fast Fourier Transform) analyzing device using SCPI it is required to support sweep measurement function. We defined SCPI command set for FFT analysis and developed parser of defined command set using lex(Lexical Analyzer Generator) and yacc(Yet Another Compiler Compiler). After developing FFT analyzing test was performed with that parser. Up to audible signal frequency the result of FFT analysis was accurate and that result was agree with that of conventional FFT analyzer. As a result it is proved that various types of instruments including sweep measurement instrument can be controlled with appropriate SCPI command sets. Also when developing new instruments the method used in this experiment will contribute to reducing the time required to develop the SCPI parser and increasing reliability.

• Journal of Welding and Joining
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• v.31 no.4
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• pp.28-33
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• 2013

The effects of laser welding beam quality is very large. However, not an analysing case was found for the difference on the plasma emission signal during laser welding according to the beam quality. Therefore, in this study, we compared and evaluated penetration and signal change according to the beam quality at the a similar wavelength band by using a fiber laser and Nd:YAG laser. In addition, we took high speed videography in order to make sure that FFT analysis reflects the actual motion period of keyhole and found the period of video analysis and FFT mostly matched. As a result, it is expected to secure higher reliability than evaluating signal intensity when appling FFT to monitoring.

• Applied Microscopy
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• v.44 no.4
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• pp.138-143
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• 2014

Transmission electron microscope (TEM) is an excellent tool for studying the structure and properties of nanostructured materials. As the development of $C_s$-corrected TEM, the direct analysis of atomic structures of nanostructured materials can be performed in the high-resolution transmission electron microscopy (HRTEM). Especially, fast Fourier transform (FFT) technique in image processing is very useful way to determine the crystal structure of HRTEM images in reciprocal space. To apply FFT technique in HRTEM analysis in more reasonable and friendly manner, we made a new circular region of interest (C-ROI) FFT script and tested it for several HRTEM analysis. Consequentially, it was proved that the new FFT application shows more quantitative and clearer results than conventional FFT script by removing the streaky artifacts in FFT pattern images. Finally, it is expected that the new FFT script gives great advantages for quantitative interpretation of HRTEM images of many nanostructured materials.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06c
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• pp.393-398
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• 1998

본 논문에서는 음성신호처리의 기초적인 해석법인 FFT와 LP분석법에 대하여 기본적인 이론과 함께 분석과정에서 알아두어야 할 사항들을 정리한다. 아울러 이러한 분석을 실제 음성신호를 대상으로 행함에 있어서 주의해야 할 점들을 실제음성을 처리한 그림과 함께 설명한다.

• Journal of Biomedical Engineering Research
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• v.24 no.3
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• pp.175-181
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• 2003

Studies of muscle fatigue have mostly been checked under isometric exercise. However EMG signals from isotonic exercise generate uncontrollable noise, so there were difficulties in gathering reliable median frequency and muscle fatigue index if frequency analysis was equally applied in isometric exercise. This study tried to compare the differences of muscle fatigue determinant variables in terms of median frequency searching methods of EMG signal, which was estimated in isotonic exercise. To accomplish this, we determined median frequency by using different FFT intervals and overlapping ration of consecutive FFT sections under the same EMG signal, and then searched for a linear regression line, and compared initial median frequency, slope, and muscle fatigue index which were variables under the linear regression line. In result of comparison, initial median frequency was more elevated as FFT exercise interval became larger. The slope of the linear regression line showed distinguishable decreasing tendency as FFT intervals were larger and overlapping sections were smaller. Significant tendency of muscle fatigue index in FFT interval was shown by high muscle fatigue index in specific FFT intervals.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.8
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• pp.30-35
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• 2006

Voltage is generally and exactly measured in the electric and electronic field. So, we studied method for detecting electric equipment faulty state using only electric voltage. It is called the Partition-FFT. Tracking is simulated by method and tester proceed on IEC 60112. We analyze voltage waveforms by tracking tester with Partition-FFT. As the result tracking process is clearly distinguished by 6 steps. Tracking is one of the major reason of electric accidents. The Partition-FFT is using a digital oscilloscope and a computer software. If Partition-FFT analysis is applied to the electricity facilities, We can prevent from happenning electric accidents cause of tacking breakdown with low prices and easy measurment. Most of all, Partition-FFT is system that make a visual tacking process. So, everyone is able to detect to possibility of electric accidents.