• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.11
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• pp.1-9
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• 1996

In the following paper, new architectural algorithm of clock and data recovery circuit is proposed for 622.08 Mbps optical communication receiver. New algorithm makes use of charge pump PLL using voltage controlled ring oscillator and extracts 8-channel 77.76 MHz clock signals, which are delayed by i/8 (i=1,2, ...8), to convert and recover 8-channel parallel data from 662.08 Mbps MRZ serial data. This circuit includes clock genration block to produce clock signals continuously even if input data doesn't exist. And synchronization of data and clock is doen by the method which compares 1/2 bit delayed onput data and decided dta by extracted clock signals. Thus, we can stabilize frequency and phase of clock signal even if input data is distorted or doesn't exist and simplify receiver architecture compared to traditional receiver's. Also it is possible ot realize clock extraction, data decision and conversion simulataneously. Verification of this algorithm is executed by DESIGN CENTER (version 6.1) using test models which are modelized by analog behavior modeling and digital circuit model, modified to process input frequency sufficiently, in SPICE.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.220-227
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• 2014

This paper presents about multi-rate sensors' synchronization and filter fusion via a sigmoid function of the Kalman filter. To synchronize multi-rate sensors, the estimation states of the Kalman filter is modified. A specific matrix that makes the filter choose sensor values only updated is multiplied to measurement matrix. For the filter that has weak points on some criteria, filter fusion is suggested by using sigmoid function. Modified kalman filter is tested with practical case. A sigmoid function was designed for the test and the performance of the modified function is estimated with respect to conventional Kalman filter. Unscented Kalman filter is used to the base filter of the suggested filter because of its stability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4A
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• pp.371-376
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• 2010

This paper presents an efficient demapper architecture based soft-decision using the phase-section for Digital Video Broadcasting via satellite, Second Generation (DVB-S2). To achieve the satisfactory performance under a very low SNR conditions with the efficient hardware resource utilization, we propose a simple soft-decision demapper architecture using comparators to compare the phase of symbols and memories. The proposed architecture can decrease about 81% of the hardware resource, satisfying the BER requirements of DVB-S2. It has been thoroughly verified with an FPGA board and R&S(R)SFU (Rohde&Schwarz SFU-K108) broadcaast test equipment.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.8
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• pp.671-677
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• 2016

A Controller Area Network (CAN) is a serial communication protocol that is highly reliable and efficient in many aspects, such as wiring cost and space, system flexibility, and network maintenance. Therefore, it is chosen for the communication protocol between a single chip controller based on Field Programmable Gate Array (FPGA) and peripheral devices. In this paper, the design and implementation of CAN IP, which is written in VHSIC Hardware Description Language (VHDL), is presented. The implemented CAN IP is based on the CAN 2.0A specification. The CAN IP consists of three processes: clock generator, bit timing, and bit streaming. The clock generator process generates a time quantum clock. The bit timing process does synchronization, receives bits from the Rx port, and transmits bits to the Tx port. The bit streaming process generates a bit stream, which is made from a message received from a micro controller subsystem, receives a bit stream from the bit timing process, and handles errors depending on the state of the CAN node and CAN message fields. The implemented CAN IP is synthesized and downloaded into SmartFusion FPGA. Simulations using ModelSim and chip test results show that the implemented CAN IP conforms to the CAN 2.0A specification.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.5B
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• pp.365-369
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• 2012

It is very important to control synchronization by inter-network delay compensation in high speed synchronous optcial transmission network systems. In this study we designed a delay measurement system based on OTDR using Rayleigh backscatterer in order to compensate for time delay due to the length of optical fiber line. We observed waveform variations on both averaging time and peak power of laser pulse. Finally, we executed experimental demonstration on its accuracy and test repeatability by comparison to the methods practically used in the industry. Experimental results show maximum error of 0.06usec and standard deviation of 0.021usec, which means it's possibly applied to delay control system for mobile repeaters and stations.

• Journal of the Korean Solar Energy Society
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• v.33 no.6
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• pp.70-76
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• 2013

Recently industrial control systems have been required to ensure intelligent, high tech automation, interconnection and interoperability demands. Therefore, there is a need to redefine the structure concepts of SCADA system for wind power. Also, at this time, the integrated management system is required for the distributed development of wind farms where are needed often interoperability features and exchange information between different wind farms, wind turbines or SCADA systems. In this paper, an integrated structural concepts for SCADA system are defined. Based on this definition of an integrated SCADA system, the basic designs are analyzed on physical layer, system layer and application layer which are corresponded to wind turbine controller, the SCADA server and the SCADA client, and implement HMI. Between the implementation SCADA server and the client, their normal functions were verified at the small scale wind energy test facilities.

• ETRI Journal
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• v.33 no.5
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• pp.670-678
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• 2011

This paper investigates the design and performance of a digital on-channel repeater (DOCR) for use in Advanced Television Systems Committee (ATSC) digital television (DTV) broadcasting. The main drawback of a DOCR is the echo interference caused by coupling between transmitter and receiver antennas, which induces system instability and performance degradation. In order to overcome this problem, an echo canceller based on the adaptive echo channel estimation (ECE) technique has been researched and applied for a DOCR. However, in the case of ATSC, the pilot signal, which is used for carrier synchronization, may cause a DC offset error and reduce the isolation performance of the echo canceller for a DOCR in an ATSC network. Moreover, since the multipath fading effect of a radio channel usually occurs in a real environment, it should be minimized to improve the overall performance of a DOCR. Therefore, due to the limited isolation performance of echo canceller and the multipath fading effect, an interference cancellation system (ICS) is proposed for a DOCR in an ATSC network. The performance of the proposed DOCR with an ICS is evaluated by software simulation and hardware test results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.517-520
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• 2003

The purpose of this paper is to investigate the effect of arc current and contact velocity on the erosion of silver contact to be used in low voltage circuit breakers. The arc current range from $2kA_{rms}$ to $20kA_{rms}$. A test system allows the control of the opening velocity profiles with contact velocities up to 10m/s and also enables the synchronization of the contact opening with a point on the arc current waveform. Contact erosion is evaluated by measuring the mass change of the cathode and anode. The results show that increase the opening velocity from 2m/s to 6m/s leads to an decrease in the contact erosion. The material transfer from one electrode to another is shown to depend on the transfer charge and the opening velocity of the contacts.

• International Journal of Highway Engineering
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• v.15 no.5
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• pp.177-185
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• 2013

PURPOSES : This study attempts to design and establish the road surface condition detection system by using the image processing that is expected to help implement the low-cost and high-efficiency road information detection system by examining technology trends in the field of road surface condition information detection and related case studies. METHODS : Adapted visual information collecting method(setting a stereo camera outside of the vehicle) and visual information algorithm(transform a Wavelet Transform, using the K-means clustering) Experiments and Analysis on Real-road, just as four states(Dry, Wet, Snow, Ice). RESULTS : Test results showed that detection rate of 95% or more was found under the wet road surface, and the detection rate of 85% or more in snowy road surface. However, the low detection rate of 30% was found under the icy road surface. CONCLUSIONS : As a method to improve the detection rate of the mobile road surface condition information detection system developed in this study, more accurate phase analysis in the image processing process was needed. If periodic synchronization through automatic settings of the camera according to weather or ambient light was not made at the time of image acquisition, a significant change in the values of polarization coefficients occurs.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.2
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• pp.117-128
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• 2008

Compared with the existing bar code system, RFID system has lots of advantages such as it identifies automatically massive objects. We might anticipate RFID technology will be a substitution for an optical bar code system in the near future. However, their feature that uses radio waves may cause various security problems. Many kinds of solutions have been researched to overcome these security problems. In this paper, we analyze the previous proposed protocols. And then, we categorize RFID authentication into two types according to the synchronization requirement between a Back-end Database and a Tag. In addition, we introduce the previous proposed approaches to tag search problem in RFID authentication. And we propose an efficient method which provides fast tag search by using membership test algorithm, a Bloom filter.