• Journal of the Korean Society for Nondestructive Testing
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• v.12 no.3
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• pp.12-19
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• 1992

This paper shows that the identified and unidentified components of surface roughness in NC turning lathe which can not be analyzed in time domain such as $R_{max},\;R_a$ can be isolated in frequency domain by FFT analyzer. By interfacing FFT analyzer with stylus surface roughness instrument, surface roughness on change of working condition, especially tool feed, such as 0.1, 0.15, 0.2, 0.25, 0.3(mm/rev) can be analyzed in frequency domain as follows. 1. By frequency analysis of surface roughness profile, the basic wave length of surface roughness can be obtained to isolate the identified and unidentified components of surface roughness. 2. With increase of tool feed, the unidentified components of surface roughness increase. 3. Since $R_{max}$, which can be obtained by stylus surface roughness is proportion to the output voltage of FFT analyzer, FFT analyzer also can be used to measure surface roughness in time domain such $R_a,\;R_{max}$.

• 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.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06c
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• pp.61-64
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• 1994

디지털 신호를 처리하기 위해 특별히 제작된 ADSP-2105는 빠른 Fied-point 연산과 Harvard-architecture로 구조화됐기 때문에 빠른 수행연산을 할 수 가 있다. 본 논문은 이 DSP 프로세서를 이용해 음성신호의 실시간 FFT 분석에 관한 방법을 소개한다. 실시간 FFT 분석기로서의 DSP 보드는 크게 음성신호를 받는 입력부분과 FFT를 계산하는 FFT 부분으로 나뉘어지는데, 입력부분은 AD1849로 8KHz로 데이터를 샘플링해 받게 되었고, FFT 부분은 실제로 DSP가 FFT를 수행하는 부분으로 되어있다. 실시간 처리를 구현하기 위해 입력 부분은 두 개의 뱅크로 만들어 한 뱅크에서 음성신호를 받아들이는 동안에 다른 뱅크에서는 FFT를 계산하도록 되어있어서 DSP 보드는 항시 음성신호를 샘플링 할 수 있는 상태를 유지할 수 있다. 그리고 FFT 처리부는 빠른 처리로 음성신호를 샘츨링할 뱅크가 채워지기 전에 실행되게 프로그램되어 있어 실제적으로 모든 음성데이타를 FFT 하게 되어있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.11
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• pp.1754-1766
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• 1993

The application of VXIbus system, an Industry standard, is rapidly spreading with its ability to offer the easiness of integration from GPIB and the fast data transmission from VMEbus system. Compared with VXIbus Register Based Device, VXIbus Message Based Device has a drawback In the aspect of speed. But it is possible to utilize high level ASCII commands to control a Message Based Device, therefore system integration is much easier with Message Based Device than with Register Based Device. And, the FFT analyzer is an instrument for signal analysis which can be inexpensively implemented to be fast and have high resolution. Its wide ability of analysis presents numerous application. So, it is necessary to apply VXIbus system to FFT analyzer. In this paper, the implementation of FFT analyzer is performed using a DSP module and by implementing all A/D conversion circuit and a control module which performs VXIbus interface. The device can be controlled by Slot0 Commender which supports VXIbus Shared Memory Protocol through VXIbus.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.6
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• pp.944-949
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• 1986

By improving the ability of arithmatic processing with an arithmatic processor in a microcomputer and realizing the data input system for real time analysis, an FFT analyzer that is usable within the range of audio frequency is designed and constructed. The input signal passes through a gain programmable pre-amplifier and anti-aliasing lowpass filter into an analogditital converter to be converted into digital form. The converted input data is processed by an Apple II microcomputer. The results of the processing are displayed using a microcomputer display unit and can be copied on a printer or stored in a floppy disk.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.497-498
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• 2009

• Journal of the Korean Institute of Intelligent Systems
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• v.7 no.2
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• pp.34-42
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• 1997

This paper deals with the recognition of closed planar shape using a three dimensional spectral feature vector which is derived from the FFT(Fast Fourier Transform) spectrum of contour sequence and fuzzy ARTMAP neural network classifier. Contour sequences obtained from 2-D planar images represent the Euclidean distance between the centroid and all boundary pixels of the shape, and are related to the overall shape of the images. The Fourier transform of contour sequence and spectrum analyzer are used as a means of feature selection and data reduction. The three dimensional spectral feature vectors are extracted by spectrum analyzer from the FFT spectrum. These spectral feature vectors are invariant to shape translation, rotation and scale transformation. The fuzzy ARTMAP neural network which is combined with two fuzzy ART modules is trained and tested with these feature vectors. The experiments including 4 aircrafts and 4 industrial parts recognition process are presented to illustrate the high performance of this proposed method in the recognition problems of noisy shapes.

• Journal of the Korean Wood Science and Technology
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• v.33 no.4 s.132
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• pp.15-22
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• 2005

The acoustic properties of various coatings for stringed musical instruments made were investigated. The applied coatings were urethane topcoat, oil stain, natural varnish, cashew and UV-curable epoxy coating. Acoustic properties of coatings inferred from a resonance frequency and a damping measured by FFT analyzer and tan ${\delta}$ measured by DMTA. Acoustic properties from resonance frequency and damping were analyzed. Optimum coating for stringed instruments was determined by viscoelastic properties and acoustic properties of coating.

• The Journal of the Acoustical Society of Korea
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• v.14 no.2
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• pp.30-39
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• 1995

In this paper, study on implementation of FFT analyzer applied to CAT, A/D conversion module, DSP module and VXIbus interface module are implemented in hardware and calculation program and control software are implemented in DSP module and VXIbus interface module, respectively. The control of the modules using PC is realized in software. The real time bandwidth of the FFT analyzing device is 100KHz. At sampling rate of 200KHz and with 2048 point FFT, the result of applying sine, triangular and rectangular wave of 20KHz to FFT analyzing device is compared with the FFT analyzed results of Hewlett-Packard 3562A dynamic output range of -40dBV- +30dBV, correct results are obtained and results of applying 10KHz, 20KHz and 50KHz input are compared and the correct values are obtained.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.12
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• pp.1314-1321
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• 2004

The non-linear responses of a slender rectangular cantilever beam subjected to lateral harmonic base-excitation are investigated by the 2-channel FFT analyzer. Both linear and nonlinear behaviors of the cantilever beam are compared with each other. Bending mode, torsional mode, and transverse mode are coupled in such a way that the energy transfer between them are observed. Especially, superharmonic, subharmonic, and chaotic motions which result from the unstable inertia terms in the transverse mode are analyzed by the FFT analyzer The aim is to give the explanations of the route to chaos, i.e., harmonic motion \longrightarrow superharmonic motion \longrightarrow subharmonic motion \longrightarrow chaos.