• Title/Summary/Keyword: Clock source

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An Analysis of Error Factors for Software Based Pseudolite Time Synchronization Performance Evaluation (소프트웨어 기반 의사위성 시각동기 기법 성능평가를 위한 오차 요소 분석)

  • Lee, Ju Hyun;Lee, Sun Yong;Hwang, Soyoung;Yu, Dong-Hui;Park, Chansik;Lee, Sang Jeong
    • Journal of Advanced Navigation Technology
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    • v.18 no.5
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    • pp.429-436
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    • 2014
  • This paper proposes three methods of the time synchronization for Pseudolite and GPS and analyzes pseudolite time synchronization error factors for software based performance evaluation on proposed time synchronization methods. Proposed three time synchronization methods are pseudolite time synchronization station construction method, method by using UTC(KRIS) clock source and GPS timing receiver based time synchronization method. Also, we analyze pseudolite time synchronization error factors such as errors of pseudolite clock and reference clock, time delay as clock transmission line, measurement error of time interval counter and error as clock synchronization algorithm to design simulation platform for performance evaluation of pseudolite time synchronization.

ASIC Implementation of Synchronization Circuit with Lossless Data Compensation (무손실 데이터 보상을 갖는 동기회로의 ASIC 구현)

  • 최진호;강호용;전문석
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.10C
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    • pp.980-986
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    • 2002
  • In the fast data communication system, synchronized by a clock source, the loss of data will often occur due to several reasons as a differential routing path between data and clock, a differential propagation delay of components or an unstable phase of clock and data by external noise. In this paper, we describe the ASIC implementation of the data compensation circuit which can detect the data loss from above problems and recovery to original data with stable synchronization. Especially it supports a strong stability and a good BER in the communication system for fast data transfer as optic area. This circuit is implemented by Verilog HDL and available to the digital ASIC implementations related to fast data transfer.

Cost Effective 60Hz FHD LCD with 800Mbps AiPi Technology

  • Nam, Hyoung-Sik;Oh, Kwan-Young;Kim, Seon-Ki;Kim, Nam-Deog;Berkeley, Brian H.;Kim, Sang-Soo;Lee, Yong-Jae;Nakajima, Keiichi
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.677-680
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    • 2008
  • AiPi technology incorporates an embedded clock and control scheme with a point-to-point bus topology, achieving the smallest possible number of interface lines between a timing controller and source drivers. A 46" AiPi-based 10-bit FHD prototype requires only 20 interface lines, compared to 38 lines for mini-LVDS. The measured maximum data rate per one data pair is more than 800Mbps.

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Sporulation of Streptomyces griseus NRRL B-2682 in Submerged Culture (방선균 Streptomyces griseus NRRL B-2682의 액내포자형성)

  • 지의상
    • The Korean Journal of Food And Nutrition
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    • v.7 no.1
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    • pp.58-63
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    • 1994
  • Sporulation of Streptomyces griseus NRRL B-2682 occurs at 26~28 hours during incubation while shaking at 3$0^{\circ}C$ in a defined medium. The time of sporulation is the same when the levels of each nutrient is increased ten times. The levels of the carbon, nitrogen and phosphate source are at a high level when sporulation begins. Sporulation of S. griseus B-2682 is clearly not caused by nutrient deprivation. It appears that a clock mechanism is involved instead. Once spores are germinated, the time of sporulation is programmed. Sporulation of S. griseus is repressed by high levels of casein hydrolysate. A study of the effect of individual amino acids revealed that L-valise when added to the normal growth medium causes an inhibition or repression of sporulation without affecting growth.

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Technological Trend of Optical Frequency Comb Generator (광 주파수 빗 발생기의 기술 동향)

  • Park, Jaegyu;Song, Minje;Han, Sang-Pil;Kim, Sungil;Song, Minhyup
    • Electronics and Telecommunications Trends
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    • v.34 no.5
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    • pp.91-98
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    • 2019
  • Optical frequency comb generators have been investigated as a signal source capable of generating highly stabilized ultrafast pulse lasers. The precise control of the optical frequency comb spacing by RF clock signals has led to a revolutionary paradigm shift in the precise measurement of time and frequency. Optical frequency combs also have advantages such as stable frequency spacing, stable number of lines, and robustness. Owing to these characteristics, optical frequency combs have been applied to the fields of high precision optical clock, communication, spectroscopy, waveform generation, and astronomy. In this article, we introduce the properties (i.e., generation methods, advantages, and so on) of various optical frequency combs, and discuss the expected future technological trends and applications.

Minimization Method of Measurement Noise for Satellite Clock Anomaly Detection (위성시계 이상검출을 위한 측정잡음 최소화 기법)

  • Seo, Kiyeol;Park, Sanghyun;Jang, Wonseok;Kim, Youngki
    • Journal of the Korean Institute of Intelligent Systems
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    • v.23 no.6
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    • pp.505-510
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    • 2013
  • In order to detect and identify the GPS clock anomaly in the Differential GPS real environment, this paper addresses a method for minimizing the measurement noise of reference receivers. It estimates the real measurement noise that removed the uncommon error source from pseudorange measurement to minimize the measurement noise. Based on the output of two reference receivers, it first removes the uncommon errors, then optimizes the measurement noise by applying the correction data. Finally, it detects and identifies the satellite clock anomaly using the minimized measurement noise. The method will increase the availability of current DGPS reference system.

Development of Machine Learning Model to Predict Hydrogen Maser Holdover Time (수소 메이저 홀드오버 시간예측을 위한 머신러닝 모델 개발)

  • Sang Jun Kim;Young Kyu Lee;Joon Hyo Rhee;Juhyun Lee;Gyeong Won Choi;Ju-Ik Oh;Donghui Yu
    • Journal of Positioning, Navigation, and Timing
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    • v.13 no.1
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    • pp.111-115
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    • 2024
  • This study builds a machine learning model optimized for clocks among various techniques in the field of artificial intelligence and applies it to clock stabilization or synchronization technology based on atomic clock noise characteristics. In addition, the possibility of providing stable source clock data is confirmed through the characteristics of machine learning predicted values during holdover of atomic clocks. The proposed machine learning model is evaluated by comparing its performance with the AutoRegressive Integrated Moving Average (ARIMA) model, an existing statistical clock prediction model. From the results of the analysis, the prediction model proposed in this study (MSE: 9.47476) has a lower MSE value than the ARIMA model (MSE: 221.2622), which means that it provides more accurate predictions. The prediction accuracy is based on understanding the complex nature of data that changes over time and how well the model reflects this. The application of a machine learning prediction model can be seen as a way to overcome the limitations of the statistical-based ARIMA model in time series prediction and achieve improved prediction performance.

The stabilization of a missile actuator using fuzzy controller (퍼지제어에 의한 미사일 조종날개용 구동모터의 안정화에 관한 연구)

  • Kim, Sang-Woo;Kwon, Yong-Soo
    • Proceedings of the KIEE Conference
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    • 1998.07a
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    • pp.18-21
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    • 1998
  • A stabilization scheme of a missile actuator using fuzzy controller is proposed. A variable-reluctance stepping motor adopted as a actuator is critically restricted useful operation since pronounced oscillatory behaviour at a certain input frequencies. The previous stabilization scheme. which employs frequency modulation, of the clock-pulse source using derived from the modulation envelope of the total intake current is modified using fuzzy control. The proposed scheme has apparent advantage, particularly in size, mass and flexibility.

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Low-Power Synchronization Technique for On-Chip Communication (온 칩 통신을 위한 저 전력 동기화 기술)

  • Lee, Jung-Hyun;Kim, Dong-Chul;Eo, Yung-Seon
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.48 no.10
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    • pp.33-38
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    • 2011
  • A novel low-power synchronization technique is presented for the local synchronization. Since the proposed technique transmits an enable signal instead of a clock signal which consumes large power, it can considerably reduce the power consumption. The source-synchronization scheme which is widely adopted for the local synchronization is compared with the proposed technique. It is shown that the proposed low-power synchronization technique provides approximately 50% power saving.

Implementation of Real-time EtherCAT Control System based on Open Source (오픈소스 기반의 실시간 EtherCAT 제어 시스템의 구현)

  • Yunjin Kyung;Dongil Choi
    • The Journal of Korea Robotics Society
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    • v.18 no.3
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    • pp.281-284
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    • 2023
  • Real-time control communication network system is important for developing defense robots because it affects environmental interaction, performance, and safety. We propose a real-time control communication network using the Xenomai real-time operating system and the open-source EtherCAT master library, SOEM. EtherCAT is an Ethernet-based industrial communication method. It has low latency and many functions such as cable redundancy and distributed clock synchronization. We use Xenomai RTOS and Intel NUC to develop the system. Experimental tests demonstrate the Real-time EtherCAT master implementation, and communication with CiA301-based slave devices. The jitter measurement was conducted to validate the real-time performance of the system. The proposed system shows possibility for real-time robotics applications in various defense robots.