• Proceedings of the KIEE Conference
• /
• 1989.11a
• /
• pp.380-382
• /
• 1989

It is necessary for us to maintain good the quality of products in iron and steel making process, especially in the rolling mill plants. Thus, we need check the stability criteria of control systems. In the frequency domain, the whole system including controllers can be identified using FFT analyzer. But this method is not adequete where precise identification is demanded. Thus a way to complement the defects In the frequency domain analysis using FFT analyzer is introduced. And In the time domain, to establish the stability criteria on the control systems, the assumed parameters obtained using least square method are presented in this report.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.05a
• /
• pp.408-413
• /
• 2003

The frequency response function(FRF) of each substructure is used for the transfer function synthesis method(TFS). The dynamic characteristics of the full system are obtained by synthesizing FRFs of each substructure. The validation of TFS depends on accuracy for FRF of each substructure. Impact hammer testing Is widely used to obtain the modal characteristics of structures However. the FRF obtained from impact hammer testing contains bias errors, such as finite record length error and leakage error of which characteristic depends on data acquisition time which we call record length. In this paper, a method to remove hose errors is proposed so as to enhance results of TFS. Numerical and experimental examples show that the FRF of full structure can be predicted nearly exactly by the method proposed in this paper.

• Journal of the Korean Society for Precision Engineering
• /
• v.12 no.10
• /
• pp.69-77
• /
• 1995

This laser measurement system has been developed using He-Ne laser and photodiode. The laser beam intensity transmitted on a photodiode was disturbed by eccentrically rotating disk cam with various speeds. The photodiode and an amplifier were used to change the detected beam intensity into voltage. The digitized data through the developed system were recorded on a micro-computer by using a signal analysis program. Its reliability was ascertained by using FFT analyzer. The vibration of rotating disk cam can be analyzed by measureing the intensity change of laser beam which the results by FFT analyzer were similar to. The amplifier was devised to be able to modulate the fluctuations of laser beam. The voltage could be linearly recorded with the change of the laser beam intensity.

• Proceedings of the KIEE Conference
• /
• 1987.07b
• /
• pp.1503-1506
• /
• 1987

This paper proposes the self test method for 16 point FFT processor with systolic array architecture. To test efficiently and solve the increased hardware problems due to built-in self test, we change the normal registers into Linear Feedback Shift Registers(LFSR). LFSR can be served as a test pattern generator or a signature analyzer during self test operation, while LFSR a ordering register or a accumulator during normal operation. From the results of logic simulation for 16 point FFT processor by YSLOG, the total time is estimated in about. 21.4 [us].

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 1996.10a
• /
• pp.211-214
• /
• 1996

This paper propose a method for pattern recogniton using spectrum analyzer and fuzzy ARTMAP. 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 transformations. The fuzzy ARTMAP neural network which is combined with two fuzzy ART modules is trained and tested with these feature vectors. The experiments include 4 aircrafts and 4 industrial parts recognition process are presented to illustrate the high performance of this proposed method in the ion problems of noisv shapes.

• Progress in Medical Physics
• /
• v.3 no.1
• /
• pp.71-78
• /
• 1992

This study describes the design of the biophysiological signal processing analyzer which can collect and analyze the biosignal raw data. System hardware is consisted of the IBM PC AT. pre-amplifier. AID converter, Counter/Timer. and RS-232C processor. Biophysiological signal data were processed by the software digital filter. FFT and graphic processing routine. The tachogram and FFT of the the peak to peak interval time was accomplished by the Graphic user interface software using the biophysiological signal processed data. Using this system. the powerspectrum of the heart rate variability during the long term could be observed. Experimental results of this system approach our purpose. which is improved the cost performance. easy to use. reducing raw-data noise and optimizing model for digital filter.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.18 no.9
• /
• pp.1332-1347
• /
• 1993

Existing instruments are composed independently according to their function and user constructed instrumentation system with those instruments. But in the late 1980s VXI bus enables to construct instrumentation system with various modular type instruments. For an VXI bus system with the word serial protocol, an increase of data size can degrade the system performance. In this paper shared memory protocol is proposed to overcome performance degradation. The shared memory protocol is analyzed using the GSPN and compared with that of the word serial protocol. It is shown that the shared memory protocol has a better performance than the word serial protocol. The VXI bus message based-system with the proposed shared memory protocol is constructed and experimented with signal generating device and FFT analyzing device. Up to 80 KHz input signal the result of FFT analysis is accurate and that result is agree with that of conventional FFT analyzer. In signal generating experiment from 100 KHz to 1.1 GHz sine wave is generated.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1993.10a
• /
• pp.357-362
• /
• 1993

In this study low priced laser measurement system was made, so its reliability was investigated Intensity distribution of laser beam measured by devised system and FFT analyzer and their results were examined for proving reliability of devised system. Transmitted laser beam intensity on photodiode changed by eccentrically rotating of disk cam and motor speed. To get results, photodiode and devised amplifier were used for changing voltage. After that, response signal was calculated by signal analysis program. It was found that the vibration of disk cam could be measured by the intensity distribution of laser beam and the same tendency was obtained by FFT. Change of motor speed effected the distribution of laser beam,which was obtained by devised system. Also linear distribution was got by sensitive balancing switch on amplifier according to the transmission of laser beam on photodide.

• Proceedings of the KIEE Conference
• /
• 1988.07a
• /
• pp.709-712
• /
• 1988

Ultrasonic Doppler Diagnostic System utilizes the Doppler effect for measurement of blood velocity. The sign of the Doppler frequency shift represents blood flow direction. CW(Continuous-Wave) Doppler System uses quadrature detection and phase rotation method to produce simultaneous independent audio and velocity signals for forward and reverse blood flow direction in the time-domain, had been fabricated. But time-domain analyzing such as audio evaluation and zero- crossing detection for instantaneous and mean frequnecy measurement do not provide both an accurate and quantitative result. Therefore, it is necessary to adopt frequency-domain technique to improve system performance. In this paper, we describe a unit which is composed of CW Doppler System and real-time spectrum analyzer (installed TMS 32010 DSP Chip). This unit shows time-dependent spectrum variation and mean velocity of Blood signal.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.4 no.1
• /
• pp.77-83
• /
• 2000

구조물의 동특성은 대형구조물을 상시감시 할 수 있는 장점으로 인하여 널리 활용된다. 상시감시를 위해 계측된 랜덤 데이터는 FFT를 통한 구조물의 동적 고유특성을 분석함으로써 이루어진다. 이 과정에서 Input Data와 Response Data사이에서 FFT Analyzer를 통하여 FRF가 측정된다. 특히 랜덤 데이터의 계측은 여건과 환경에 따라 발생하는 Noise로부터 가능한 정확한 FRF를 계측해야만 성공적인 구조물의 고유의 동적특성을 파악하게 된다. 랜덤 데이터에서 발생할 가능성이 높은 입력, 출력 Noise를 동시에 최소화 할 수 있는 새로운 개념의 FRF측정 알고리즘을 제안한다. 이 알고리즘에 의하여 장대형 모형교량으로부터 Modal 실험을 수행하여 계측된 동특성을 FE 해석 결과와 비교 평가하여 유용성을 제시한다.