• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.518-521
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• 1998

This paper describes a 3.3V-65MHz 12BIT CMOS current-mode DAC designed with a 8 MSB current matirx stage and a 4 LSB binary weighting stage. The linearity errors caused by a voltage drop of the ground line and a threshold voltage mismatch of transistors have been reduced by the symmetrical routing method with ground line and the tree structure bias circuit, respectively. In order to realize a low glitch energy, a cascode current switch ahs been employed. The simulation results of the designed DAC show a coversion rate of 65MHz, a powr dissipation of 71.7mW, a DNL of .+-.0.2LSB and an INL of .+-.0.8LSB with a single powr supply of 3.3V for a CMOS 0.6.mu.m n-well technology.

• 산업기술연구
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• 제22권B호
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• pp.133-139
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• 2002

In precision instrumentation system, an A/D conversion of signal conditioning has been always suffered from some problems ; offset and drift voltage with environmental situation. This paper suggests a method of reducing the offset voltage and the drift error from the A/D conversion hardware using analog signal switching technique with specific operational amplifier circuits. Also, we have designed a hardware active filter and a software digital filter with Auto Zero Tracking algorithm for better dignal process of the our proposed weighing system. Software technique was performed to obtain the stable data from A/D converter. As a result of our experimental works, the proposed system is expected to be used in the industrial field where a high precision measurement is required.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.449-450
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• 2008

In this paper, we present the design of a system on a chip(SoC) based on Powerline Communication for Power-IT. The SoC deals with power information obtained from analog to digital converter and transmits this data via powerline. We integrate main processor, ADC and PLC function into a chip. Also a FPGA-based emulation system is introduced to evaluate a proposed SoC architecture.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.158.1-158
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• 2001

An algorithmic gray code analog-to-digital converter (ADC), which is based on gray coding, is proposed in this article. The realization method makes use of a MOS triangular function circuit to provide a high-speed operation and low accumulated error. The proposed ADC is simple, small in size and suitable for fabrication using a standard CMOS process. Simulation results showing the performances of the proposed circuit are also included.

• 한국ITS학회 논문지
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• 제10권4호
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• pp.100-106
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• 2011

무선통신환경에서는 RF신호가 매우 심하게 변하는데, 이러한 신호의 변화는 특히 차량통신환경에서 더욱 심해진다. 자동이득제어는 무선통신시스템에서 신뢰성 있는 통신환경을 제공하고 급격하게 변하는 수신신호를 보상하데 중요한 역할을 한다. 본 논문에서는 수신신호세기값과 아날로그-디지털변환값 두 가지 신호를 이용하는 간단하고 향상된 자동이득 제어기법에 대해 논의한다. 시물레이션과 실제 환경에의 측정을 통해 제안된 기법의 성능을 검증한다.

• 산업기술연구
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• 제25권A호
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• pp.183-189
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• 2005

In precision instrumentation system, an A/D conversion of signal conditioning has some problems.; offset and drift errors with environmental situation. This paper suggested a development of the Multi-Channel A/D Data Acquisition System and a method of the evaluation and the temperature compensation for the A/D converters with the specific analog and digital circuit including the software. Also, we have designed a hardware and a software filters with smart algorithm for better signal processing of the proposed system. Software approach was adopted to obtain the stable data from A/D converter. As shown in our experimental works, the proposed system is expected to be used in the industrial field where a high precision measurement is required.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.833-836
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• 2007

A low power and small area source driver using LTPS TFTs is proposed for mobile applications. This source driver adopts level shifter with holding latch function and new R-to-R type digital-to-analog converter (DAC). The power consumption and layout area of the proposed source driver are reduced by 23% and 25% for 16M colors and qVGA AM-OLED panel, respectively.

• Journal of Biosystems Engineering
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• 제14권4호
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• pp.221-228
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• 1989

A data acquisition system was designed to measure the forces on a rolling coulter in three coordinated directions, angular velocity of the coulter and travel speed of a soil bin. The data acquisition system consisted of a dynamometer, speed transducers, a signal conditioner, an inter-face board, an Aim-65 microcomputer and a digital data recorder. Strain gages were attached on the surface of the dynamometer and connected to form three Wheatstone bridges, which measure the draft force, the vertical force and the side force on the coulter. An interaction among three dimensional forces was found during the calibration. A matrix procedure was used to correct the forces for this interaction. Rotary shaft encoders were mounted on the coulter and on the soil bin drive to measure the angular velocity of the coulter and the travel speed of the soil bin. The angular velocity and the travel speed were computed by counting the number of pulse signals from the rotary shaft encoders every 0.2 second. The digital signals from the rotary shaft encoders were connected to counters and the analog signals from the dynamometer, after passing through the signal conditioner, were connected to the A/D converter. The microcomputer programs, written in assembly language, were developed to read signals from the transducers, convert them to actual unit, display them upon request and record them on a sigital tape every 0.2 second.

• 치과방사선
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• 제25권2호
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• pp.363-373
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• 1995

The aim of this study was to evaluate and compare observer performance between conventional radiographs and their digitized images for the detection of bone loss in the bifurcation of mandiblar first molar. One dried human mandible with minimal periodontal bone loss around the first molar was selected and serially enlarged 17 step defects were prepared in the bifurcation area. The mandible was radiographed with exposure time of 0.12, 0.20, 0.25, 0.32, 0.40, 0.64 seconds, after each successive step in the preperation and all radiographs were digitized with IBM-PC/32 bit-Dx compatible, video camera (VM-S8200, Hitachi Co., Japan), and color monitor(Multisync 3D, NEC, Japan). Sylvia Image Capture Board for the ADC(analog to digital converter) was used. The obtained results were as follows: 1. In the conventional radiographs, the mean score of the readability was higher at the condition of exposure time with 0.32 second. Also, as the size of artificial lesion was increased, the readability of radiographs was elevated (P<0.05). 2. In the digital images, the mean score of the readability was higher at the condition of exposure time with 0.40 second. Also, as the size of artificial lesion was increased, the readability of digital images was elevated(P<0.05). 3. At the same exposure time, the mean scores of readibility were mostly higher in the digitized images. As the exposure time was increased, the digital images were superior to radiographs in readability. 4. As the size of lesion was changed, the digital images were superior to radiographs in detecting small lesion. 5. The coefficient of variation of mean score has no significant difference between digital images and radiographs.

• 한국정밀공학회지
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• 제19권10호
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• pp.139-146
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• 2002

We developed a motion capture system to utilize informations on the human walking motion. The system is composed of the mechanical and electronic devices to obtain the joint angle data and the software to analyze the obtained data and to transform the data into the input for a biped walking robot. The mechanical system is composed of a pair of links with 3 revolute joints, on which potentiometers are attached on joint axes to sense rotation angles. Analog signals from potentiometers are transformed into the digital data through the low pass filter and the A/D converter, and then which are stored at the computer. We analyzed the walking characteristics by applying FFT to the digital data, and then performed a 3-D computer simulation using the data. Finally, We apply the processed data to a biped walking robot.