• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.29 no.3
• /
• pp.69-80
• /
• 2015

This paper is writing about developing magnet power supply. It is very important for power supply to obtain output current in high precision and high stability. As a switching noise and a power noise are the cause of disrupting the stability of output current, to remove these at the front end, low pass filter with 300Hz cutoff frequency is designed and placed. And also to minimize switching noise of the current into magnet and to stop abrupt fluctuations, output filter should be designed, when doing this, we design it by considering load has high value inductance. As power supply demands the stability of less than 5ppm, high precision 24bit(300nV/bit) analog digital converter is needed. As resolving power of 24bit(300nV/bit) analog digital converter is high, it is also very important to design the input stage of analog digital converter. To remove input noise, 4th order low pass filter is composed. Due to the limitation of clock, to minimize quantization error between 15bit DPWM and output of ADC having 24bit resolving power, ${\Sigma}-{\Delta}$ modulation is used and bit contracted DPWM is constituted. And before implementing, to maximize efficiency, simulink is used.

• Proceedings of the KOSOMBE Conference
• /
• v.1994 no.05
• /
• pp.53-56
• /
• 1994

We have developed biological signal measurement modules and data acquisition and control card for a biological signal measurement, archiving, and communication system (SiMACS). Biological signals included in this system are ECG, EEG, EMG, invasive blood pressure, respiration, and temperature. Parameters of each module can be controlled by PC-base IDPU (intelligent data processing unit) through a data acquisition and control card. The data acquisition and control card can collect up to 16 channels of biological signals with sampling rate of $50\;{\sim}\;2,000Hz$ and 12-bit resolution. All measurement moduls and data acquisition functions are controlled by microcontroller which receives commands from PC. All data transfers among PC, microcontroller, and ADC are done through a shared RAM access by polling method for real rime operation.

• Annals of Clinical Neurophysiology
• /
• v.8 no.2
• /
• pp.186-189
• /
• 2006

A 69 year-old woman was admitted with sudden left facial weakness. She had no other neurologic deficit, except for left peripheral type facial palsy. She had a presumptive diagnosis of Bell's palsy. The blink test was indicative of left facial neuropathy due to left medullary lesion. Diffusion weighted (DWI) brain MRI demonstrated high signal signal lesion in left dorsolateral ponto-medullary junction. Apperant diffusion coefficient (ADC) brain MRI showed low signal lesion in the same area. We present an unusual case of ipsilateral peripheral facial palsy in dosolateral ponto-medullary infarction without other neurologic deficits.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.6C
• /
• pp.498-504
• /
• 2008

In this paper, an efficient hardware platform for the digital signal processing for OFDM Communication systems is presented. The hardware platform consists of a single FPGA, two DSPs with 8000 MIPS of maximum at 1 GHz clock, 2-channel ADC and DAC supporting maximum 125 MHz sampling rate, and flexible data bus architecture, so that a wide variety of baseband signal processing algorithms for practical OFDM communication systems may be implemented and tested. The IEEE 802.16 software modem is also presented in order to verify the effectiveness and usefulness of the designed platform.

• Proceedings of the IEEK Conference
• /
• summer
• /
• pp.199-203
• /
• 2004

In this paper, we only describe the digital block of two-channel 18-bit analog-to-digital (A/D) converter employing sigma-delta method and xl28 decimation. The device contains two fourth comb filters with 1-bit input from sigma­delta modulator. each followed by a digital half band FIR(Finite Impulse Response) filters. The external analog sigma-delta modulators are sampled at 6.144MHz and the digital words are output at 48kHz. The fourth-order comb filter has designed 3 types of ways for optimal power consumption and signal-to-noise ratio. The following 3 digital filters are designed with 12tap, 22tap and 116tap to meet the specification. These filters eliminate images of the base band audio signal that exist at multiples of the input sample rate. We also designed these filters with 8bit and 16bit filter coefficient to analysis signal-to-noise ratio and hardware complexity. It also included digital output interface block for I2S serial data protocol, test circuit and internal input vector generator. It is fabricated with 0.35um HYNIX standard CMOS cell library with 3.3V supply voltage and the chip size is 2000um by 2000um. The function and the performance have been verified using Verilog XL logic simulator and Matlab tool.

• Journal of Institute of Control, Robotics and Systems
• /
• v.7 no.10
• /
• pp.837-842
• /
• 2001

In this paper, we design and implement the DC characteristic measurement system for semiconductor devices. The proposed system is composed of 4 SMU(Source and Measure Unit) channels. Various efforts in hardware and software have been made to reduce the measurement errors. Internal and external sources of errors in measurement system especially in pA range measurement have been identified and removed. Also, various digital signal processing techniques are developed. Calibration is executed under the control of microprocessor periodically. Experimental results show that the implemented system can measure the DC characteristic of semiconductor devices with less than 0.2% error in various voltage and current source/measurement range.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.4 no.2
• /
• pp.63-70
• /
• 2003

In this paper, an MFC (Mass Flow Controller) which is widely used in many semiconductor manufacturing processes for controlling the mass flow rate of a gas is designed and implemented using the PIC 16F876 of Microchip, Inc. The MFC implemented in this thesis has the form of hybrid-type, i.e., the mixed-type of the analog-type MFC, which has many problems such as low accurary, and digital-type MFC, which use an expensive DSP (Digital Signal Processor) and an ADC (Analog to Digital Convertor) with high precision. The MFC is consists of the sensor unit, the control unit and the actuator unit, and it has used the automatic calibration algorithm and the reference table method for the improvement of the performance.

• Journal of Power Electronics
• /
• v.9 no.2
• /
• pp.224-231
• /
• 2009

The induction motor rotor fault diagnosis system using current signals, which are measured using an axis-transformation method, is presented in this paper. In inverter-fed motor drives, unlike line-driven motor drives, the stator currents are rich in harmonics; therefore fault diagnosis using stator current is not trivial. The current signals for rotor fault diagnosis need precise and high resolution information, which means the diagnosis system demands additional hardware such as a low pass filter, high resolution ADC, and encoder, etc. The proposed axis-transformation method with encoder and without encoder is expected to contribute to a low cost fault diagnosis system in inverter-fed motor drives without the need for any additional hardware. In order to confirm the validity of the developed algorithms, various experiments for rotor faults are tested and the line current spectrum of each faulty situation using Park transformation is compared with the results obtained from fast Fourier transforms.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.25 no.11
• /
• pp.1619-1626
• /
• 2021

Unlike traditional delta-sigma analog-to-digital converters, incremental analog-to-digital converters enable 1:1 mapping of input and output through a reset operation, which can be used very easily for multiplexing. Incremental analog-to-digital converters also allow for simpler digital filter designs compared to traditional delta-sigma converters. Therefore, starting with analysis in the time domain of the delayed integrator and non-delayed integrator, which are the basic blocks of analog-to-digital converter design, the design equations of a second-order input feed-forward, extended counting, 2+1 MASH (Multi-stAge-noise-SHaping), 2+2 MASH incremental analog-to-digital converter are derived in this paper. This allows not only prediction of the performance of the incremental analog-to-digital converter before design, but also the design of a digital filter suitable for each analog-to-digital converter. In addition, extended counting and MASH design techniques were proposed to improve the accuracy of analog-to-digital converters.

• Journal of Korean Society of Forest Science
• /
• v.100 no.3
• /
• pp.374-381
• /
• 2011

The purpose of this study is to examine the possibility of early detection of Pine Wilt Disease (PWD) using NDVI (Normalized Difference Vegetation Index) from ADC (Agricultural Digital Camera) imageries. The PWD induces the different patterns of reduction of NDVI between healthy trees and infected trees, due to the withered leaves on the infected trees. Based on these phenomena, the DI showing the NDVI variations of trees by time series was employed to detect the infected trees. To find out the differences of DI level between normal and infected trees, DIs of trees from May to August in 2007 were calculated and these were analyzed with GLM (General Linear Models) in SAS 9.2. As a result, the difference of DI between in June and August shows the most significant level (0.0001). The discriminant analysis was performed between normal and infected trees, using the DI of June and August. As the result, hit ratio of trees and the accuracy of grouping with Jack-knife method were shown 71.9% and 73.5%, respectively. These results showed that the DI is effective to detect the trees infected by the PWD and it is useful to prevent the PWD.