• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.1
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• pp.150-158
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• 2010

Filtering is necessary for the SRC(sample rate converter), that is used to change the sampling rate of a digital signal. The larger the conversion ratio of the sampling rate becomes, the more signal processing is needed for the filter, which means more complexity on realization. Thus it is important to reduce the amount of signal processing for the case of substantial conversion ratios. In this paper it is presented an efficient design method of a multistage FIR(finite impulse response) filter, with which the rate conversion occurs in stages rather than in one step. In this method, filter searching is performed exhaustively over all possible factorization of the conversion ratio, and also the filter complexity is measured based on direct realization rather than on estimation. It has been shown a designed multistage filter to have a less number of multiplications for filtering operation in comparison with a conventionally designed one. It has also been found that by allowing some variations of the filter architecture such as a halfband filter or a filter with multiple transition bands, the number of multiplications can be reduced further.

• Journal of the Korean Institute of Gas
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• v.26 no.2
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• pp.21-26
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• 2022

Since the four-wheel drive transmits the driving force to all four wheels, the traction with the road surface increases, thereby increasing the driving force. However, it has the disadvantage of lowering fuel efficiency. Therefore, four-wheel drive is commonly used as a method of converting to optional four-wheel drive when necessary while driving in two-wheel drive. This selective four-wheel drive converts the driving force by mechanically changing the electric signal sent by the driver in the transfer case. In this study, in order to mechanically change the electrical signal, a reducer is applied to the motor to increase the torque to perform the function. Therefore, in this study, a reduction mechanism applicable to the motor inside the transfer case applied to convert the drive is derived, and the reduction ratio applying the planetary gear type is optimized accordingly. And based on the derived reduction ratio, two sets of planetary gears using a ring gear in common were applied to develop a planetary gear tooth type in which the input shaft and output shaft are decelerated in the same phase. Optimization design was carried out.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.823-830
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• 2010

This paper deals with a coaxial-to-waveguide transition generating circularly polarized wave to be connected with horn antennas. By combining vertical coaxial fed structure, back-short and the polarization twisting structure, the circular polarization is successfully generated in the waveguide. The designed and implemented transition shows that the present structure can significantly reduce the size of the antenna part at X-band.

• Journal of IKEEE
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• v.14 no.2
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• pp.16-23
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• 2010

Since the interest of a brain science research is increased recently, various devices using brain waves have been developed in the field of brain training game, education application and brain computer interface. In this paper, we have developed a portable EEG measurement and a bluetooth based wireless transmission device measuring brain waves from the frontal lob simply and conveniently. The low brain signals about 10~100${\mu}V$ was amplified into several volts and low pass, high pass and notch filter were designed for eliminating unwanted noise and 60Hz power noise. Also, PIC24F192 microcontroller has been used to convert analog brain signal into digital signal and transmit the signal into personal computer wirelessly. The sampling rate of 1KHz and bluetooth based wireless transmission with 38,400bps were used. The LabVIEW programing was used to receive and monitor the brain signals. The power spectrum of commercial biopac MP100 and that of a developed EEG system was compared for performance verification after the simulation signals of sine waves of $1{\mu}V$, 0~200Hz was inputed and processed by FFT transformation. As a result of comparison, the developed system showed good performance because frequency response of a developed system was similar to that of a commercial biopac MP100 inside the range of 30Hz specially.

• Journal of Biomedical Engineering Research
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• v.7 no.2
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• pp.139-146
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• 1986

Pulsed ultrasonic Doppler system is a useful diagnostic instrument to measure blood-flow-velocity, velocity profile, and volume-blood-flow. This system is more powerful compare with 2-dimensional B-scan tissue image. A system has been deve- loped and ii being evaluated using TMS 32010 DSP. We use this DSP for the purpose of real-time spectrum analyzer to obtain spectrogram in singlegate pulsed Doppler system and for the serial comb filter to cancel clutter and zero crossing counter to estimate Doppler mean frequency in multigate pulsed Doppler system. The Doppler shift of the backscattered signals is sensed in a phase detector. This Doppler signal corresponds to the mean velocity over a some region in space defined by the ultrasonic beam dimensions, transmitted pulse duration, and transducer ban(iwidth. Multi- gate pulsed Doppler system enable the transcutaneous and simultaneous assessment of the velocities in a number of adjacent sample volumes as a continuous function of time. A multigate pulsed Doppler system processing the information originating from presented.

• Electrical & Electronic Materials
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• v.17 no.8
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• pp.25-32
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• 2004

센서는 인간의 오감에 해당하는 감지기로서 온도, 소리, 빛 등의 물리, 화학적 신호를 전기적 신호로 변환시켜주는 일련의 장치를 말한다. 물론 센서에 대한 정의 및 분류 방법은 다양하게 표현될 수 있으나 본 논문에서는 MEMS(Micro Electro-Mechanical System) 기술을 적용하여 Smart화 혹은 Wireless화에 필요한 Micro 센서로 그 범위를 한정하고자 한다. 만일 센서를 아주 작게(Micro Sensor) 만들 수 있고 그것들끼리 무선으로 연결될 수(Wireless Network) 있다면 우리의 삶의 형태는 지금과는 매우 다른 모습으로 전개 될 것이다. 그림 1은 2004년에 정보통신부가 발표한 Ubiquitous Sensor Network의 개념도이다.(중략)

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.293-295
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• 1999

피 측정물의 변위를 기계적 변화로 감지하여 나타내는 LVDT는 상호인덕턴스 변화를 이용하는 대표적 변위 트랜스듀서이다. 본 연구에서는 LVDT에 대한 상품화를 위한 설계와 제작, 그리고 신호변환장치에 대한 과정을 기술하였으며, 최종 성능 특성을 측정하여 상품화를 위한 신뢰성의 정도와 선형도 등을 평가하였다. 이러한 상품화 과정을 통하여 산업현장에서 자동계측과 제어를 위한 트랜스듀서로 활용할 수 있도록 하고자 한다.

• Proceedings of the Optical Society of Korea Conference
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• 1988.06a
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• pp.112-116
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• 1988

Homodyne 방식으로 동작하는 광섬유 간섭계 센서는 주위 온도의 변화나 진동등에 의하여 시노의 크기가 불규칙하게 변화된다. 따라서 광섬유 간섭계가 직작조건에서 동작하도록 하여 감도를 최대로 유지시켜야 한다. 본연구에서는 원통형 압전자소자에 단일모드 광섬유룰 감아서 변환율 K=1.07$\pi$/V의 위상변조기를 만들고, 이를 이용하여 능동위상추적(active phase tracking)방식의 신호안정화 장치를 제작하고 광섬유 간섭계 센서의 공기중 읍압반응을 조사하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.11
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• pp.2412-2418
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• 2009

As an astonishing progress of FTTH infrastructure, the new technologies have been widely studied to use the tantalizing benefits of high bandwidth in fiber optic cable. In this paper, a new VONU is presented to perform all necessary optical functions. It can converts digital and analog CATV signals and satellite-based signal transmitted via one fiber optic cable to electrical signals (electric lights). However, most previous VONU systems have the problems such as interference between difference services, signal distortion, and noise increasing rate. These problems cause the quality deterioration in broadcasting. Therefore, we suggest the new VONU system to solve all problems listed above. In addition, we show that how our system performs well by measuring the real data with implemented system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.281-281
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• 2004

본 논문에서는 레이들(ladle)에 실린 용강의 균일한 혼합을 위해 사용되는 저취 시스템의 버블 강도를 예측하기 위해 진동센서를 이용한 안착대를 설계하고 제작하였다 또한 무선 인터넷을 이용해 안착대로부터 진동 데이터를 수신하여 실시간으로 원격지에 위치한 서버에 저장하는 시스템을 구현하였다. 이와 함께 저취 시스템에 사용되는 유량제어밸브를 컨트롤하기 위해 기존에 사용되는 프로토콜 변환기를 변경한 데이터 처리장치를 설계하고 제작하였다. 데이터처리장치는 4개의 직렬 신호를 동시에 처리 가능하며 비구조화된 데이터를 보관하다록 하기 위해 플래쉬 메모리를 장착하였으며, CPU의 데이터 처리를 위해 SRAM을 장착하도록 구성하였다.(중략)