• Title/Summary/Keyword: Offset algorithm

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A Symbol Timing Recovery scheme using the jitter mean of adaptive loop filter in ATSC DTV systems (적응적 루프필터의 지터 평균값을 이용한 ATSC DTV 심볼 타이밍 동기 방식)

  • Kim, Joo-Kyoung;Lee, Joo-hyoung;Song, Hyun-keun;Kim, Jae-Moung;Kim, Seung-Won
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.42 no.10 s.340
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    • pp.1-8
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    • 2005
  • This Paper Proposes the algorithm for improving the Performance or symbol timing synchronization in hoc terrestrial DTV system. The Gardner algerian is used for symbol timing synchronization has good performance in multipath fading environment but degradation of performance is caused by jitter. Though the amount of jitter becomes more little as narrow bandwidth of loop Inter, convergence speed becomes slower. This paper propose the algorithm that averages out values of loop filter every certain time and gradually reduces the bandwidth of loop filter after estimating offset using this average for the high speed of convergence and reducing the met of jitter. The proposed algorithm has better performance with high speed of convergence and the amount of jitter than conventional method.

Design of Carrier Recovery Circuit for High-Order QAM - Part II : Performance Analysis and Design of the Gear-shift PLL with ATC(Automatic Transfer-mode Controller) and Average-mode-change Circuit (High-Order QAM에 적합한 반송파 동기회로 설계 - II부. 자동모드전환시점 검출기 및 평균모드전환회로를 적용한 Gear-Shift PLL 설계 및 성능평가)

  • Kim, Ki-Yun;Kim, Sin-Jae;Choi, Hyung-Jin
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.38 no.4
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    • pp.18-26
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    • 2001
  • In this paper, we propose an ATC(Automatic Transfer mode Controller) algorithm and an average-mode-change method for use in Gear shift PLL which can automatically change loop gain. The proposed ATC algorithm accurately detects proper timing or the mode change and has a very simpler structure - than the conventional lock detector algorithm often used in QPSK. And the proposed average mode change method can obtain low errors of estimated frequency offset by averaging the loop filter output of frequency component in shift register. These algorithms are also useful in designing ASIC, since these algorithms occupy small circuit area and are adaptable for high speed digital processing. We also present phase tracking performance of proposed Gear-shift PLL, which is composed of polarity decision PD, ATC and average mode change circuit, and analyze the results by examining constellation at each mode.

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A Study on Vehicle to Road Tracking Methodology with Consideration of vehicle lateral dynamics (차량 횡방향 운동 방정식을 고려한 차대도로간 트래킹 기법)

  • Shin, Dongho
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.16 no.6
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    • pp.219-230
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    • 2017
  • This paper proposes a vehicle to road tracking algorithm based on vision sensor by using EKF(Extended Kalman Filter). The lateral offset, heading angle, and curvature which are obtained from vehicle to road tracking might be used as inputs to steering controller of LKAS(Lane Keeping Assist System) or for the warning decision logic of LDWS(Lane Departure Warning System). To the end, in this paper, the yaw rate, steering angle, and vehicle speed as well as lane raw points together with considering of vehicle lateral dynamics are utilized to improve the exactness and convergence of the vehicle to road tracking. The proposed algorithm has been tested at a proving ground that consists of straight and curve sections and compared with GPS datum using DGPS-RTK equipment to show the feasibility of the proposed algorithm.

Meaurement Algorithms for EDGE Terminal Performance Test (EDGE 단말기 성능 테스트를 위한 측정 알고리즘)

  • Kang, Sung-Jin;Hong, Dae-Ki;Kim, Nam-Yong
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.12
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    • pp.2719-2730
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    • 2009
  • In this paper, we implement the measurement functionality for performance measurements of EDGE (Enhanced Data Rates for GSM Evolution) terminal by using software. Generally speaking, the receiving algorithms in normal MODEM cannot be used directly to a measurement system due to the lack of accuracy. Therefore, we propose a new receiver algorithm for precise EDGE signal measurements. In the proposed algorithm, 2-stage (coarse stage, fine stage) parameters estimation (symbol-timing, frequency offset, carrier phase) scheme is used. To improve the estimation accuracy, we increase the number of the received signal samples by interpolation. The proposed EDGE signal measurement algorithm can be used for verifying the hardware measurement system, and also can be used for the commercial systems through software optimization.

Clock Synchronization for Multi-Static Radar Under Non-Line-of-Sight System Using Robust Least M-Estimation (로버스트한 최소 M-추정기법을 이용한 비가시선 상의 멀티스태틱 레이더 클락 동기 기술 연구)

  • Shin, Hyuk-Soo;Yeo, Kwang-Goo;Joeng, Myung-Deuk;Yang, Hoongee;Jung, Yongsik;Chung, Wonzoo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37C no.10
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    • pp.1004-1010
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    • 2012
  • In this paper, we propose the algorithm which considers applying recently proposed clock synchronization techniques with quite high accuracy in a few wireless sensor networks researches to time synchronization algorithm for multi-static radar system and especially overcomes the limitation of previous theory, cannot be applied between nodes in non-line of sight (NLOS). Proposed scheme estimates clock skew and clock offset using recursive robust least M-estimator with information of time stamp observations. And we improve the performance of algorithm by tracking and suppressing the time delays difference caused by NLOS system. Futhermore, this paper derive the mean square error (MSE) to present the performance of the proposed estimator and comparative analysis with previous methods.

Genetic Algorithm Calibration Method and PnP Platform for Multimodal Sensor Systems (멀티모달 센서 시스템용 유전자 알고리즘 보정기 및 PnP 플랫폼)

  • Lee, Jea Hack;Kim, Byung-Soo;Park, Hyun-Moon;Kim, Dong-Sun;Kwon, Jin-San
    • The Journal of the Korea institute of electronic communication sciences
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    • v.14 no.1
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    • pp.69-80
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    • 2019
  • This paper proposes a multimodal sensor platform which supports plug and play (PnP) technology. PnP technology automatically recognizes a connected sensor module and an application program easily controls a sensor. To verify a multimodal platform for PnP technology, we build up a firmware and have the experiment on a sensor system. When a sensor module is connected to the platform, a firmware recognizes the sensor module and reads sensor data. As a result, it provides PnP technology to simply plug sensors without any software configuration. Measured sensor raw data suffer from various distortions such as gain, offset, and non-linearity errors. Therefore, we introduce a polynomial calculation to compensate for sensor distortions. To find the optimal coefficients for sensor calibration, we apply a genetic algorithm which reduces the calibration time. It achieves reasonable performance using only a few data points with reducing 97% error in the worst case. The platform supports various protocols for multimodal sensors, i.e., UART, I2C, I2S, SPI, and GPIO.

Development of Easy-to-Use Crane-Tip Controller for Forestry Crane

  • Ki-Duck, Kim;Beom-Soo, Shin
    • Journal of Forest and Environmental Science
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    • v.38 no.4
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    • pp.239-248
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    • 2022
  • Forestry crane work in a forest harvester or forwarder is regarded as one of most hard work requiring a very high level of operation skill. The operator must handle two or more multi-axes joysticks simultaneously to control the multiple manipulators for maneuvering the crane-tip to its intended location. This study has been carried out to develop a crane-tip controller which can intuitively maneuver the crane-tip, resulting in improving the productivity by decreasing the technical difficulty of control as well as reducing the workload. The crane-tip controller consists of a single 2-axis joystick and a control algorithm run on microcontroller. Lab-scale forestry crane was constructed using electric cylinders. The crane-tip control algorithm has the crane-tip follow the waypoints generated on the given path considering the dead band region using LBO (Lateral Boundary Offset). A speed control gain to change the speed of relevant cylinders relatively is applied as well. By the P (Proportional) control within the control interval of 20 msec, the average error of crane-tip control on the predefined straight path turned out to be 14.5 mm in all directions. When the joystick is used the waypoints are generated in real time by the direction signal from the joystick. In this case, the average error of path control was 12.4 mm for straight up, straight forward and straight down movements successively at a certain constant speed setting. In the slant movement of crane-tip by controlling two axes of joystick simultaneously, the movement of crane-tip was controlled in the average error of 15.9 mm when the crane-tip is moved up and down while moving toward forward direction. It concluded that the crane-tip control was possible using the control algorithm developed in this study.

A constrained minimization-based scheme against susceptibility of drift angle identification to parameters estimation error from measurements of one floor

  • Kangqian Xu;Akira Mita;Dawei Li;Songtao Xue;Xianzhi Li
    • Smart Structures and Systems
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    • v.33 no.2
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    • pp.119-131
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    • 2024
  • Drift angle is a significant index for diagnosing post-event structures. A common way to estimate this drift response is by using modal parameters identified under natural excitations. Although the modal parameters of shear structures cannot be identified accurately in the real environment, the identification error has little impact on the estimation when measurements from several floors are used. However, the estimation accuracy falls dramatically when there is only one accelerometer. This paper describes the susceptibility of single sensor identification to modelling error and simulations that preliminarily verified this characteristic. To make a robust evaluation from measurements of one floor of shear structures based on imprecisely identified parameters, a novel scheme is devised to approximately correct the mode shapes with respect to fictitious frequencies generated with a genetic algorithm; in particular, the scheme uses constrained minimization to take both the mathematical aspect and the realistic aspect of the mode shapes into account. The algorithm was validated by using a full-scale shear building. The differences between single-sensor and multiple-sensor estimations were analyzed. It was found that, as the number of accelerometers decreases, the error rises due to insufficient data and becomes very high when there is only one sensor. Moreover, when measurements for only one floor are available, the proposed method yields more precise and appropriate mode shapes, leading to a better estimation on the drift angle of the lower floors compared with a method designed for multiple sensors. As well, it is shown that the reduction in space complexity is offset by increasing the computation complexity.

Implementation of the Color Matching Between Mobile Camera and Mobile LCD Based on RGB LUT (모바일 폰의 카메라와 LCD 모듈간의 RGB 참조표에 기반한 색 정합의 구현)

  • Son Chang-Hwan;Park Kee-Hyon;Lee Cheol-Hee;Ha Yeong-Ho
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.43 no.3 s.309
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    • pp.25-33
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    • 2006
  • This paper proposed device-independent color matching algorithm based on the 3D RGB lookup table (LUT) between mobile camera and mobile LCD (Liquid Crystal Display) to improve the color-fidelity. Proposed algorithm is composed of thee steps, which is device characterization, gamut mapping, 3D RGB-LUT design. First, the characterization of mobile LCD is executed using the sigmoidal function, different from conventional method such as GOG (Gain Offset Gamma) and S-curve modeling, based on the observation of electro-optical transfer function of mobile LCD. Next, mobile camera characterization is conducted by fitting the digital value of GretagColor chart captured under the daylight environment (D65) and tristimulus values (CIELAB) using the polynomial regression. However, the CIELAB values estimated by polynomial regression exceed the maximum boundary of the CIELAB color space. Therefore, these values are corrected by linear compression of the lightness and chroma. Finally, gamut mapping is used to overcome the gamut difference between mobile camera and moible LCD. To implement the real-time processing, 3D RGB-LUT is designed based on the 3D RGB-LUT and its performance is evaluated and compared with conventional method.

OFDM/OQAM-IOTA System With Odd/Even Center Preamble Structure (Odd/Even Center Preamble 구조를 가진 OFDM/OQAM-IOTA 시스템)

  • Kang, Seung-Won;Heo, Joo;Chang, Kyung-Hi
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.12A
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    • pp.1153-1160
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    • 2005
  • OFDM/OQAM(Offset QAM)-IOTA system requires the IOTA(Isotropic Orthogonal Transform Algorithm) function that has superior localization property in time and frequency domain instead of guard interval used for conventional OFDM/QAM system to be robust to multipath channel. Therefore, OFDM/OQAM-IOTA system has more spectral efficiency than conventional OFDM/QAM system. But, when channel estimation scheme for conventional OFDM/QAM system is applied straightforwardly to OFDM/OQAM-IOTA system, an intrinsic Inter- symbol-Interference is observed. So suitable preamble structure for the channel estimation scheme of OFDM/OQAM-IOTA system is required. In this paper, we propose a new preamble structure that is appropriate to OPDM/OQAM-IOTA system and then perform ideal channel estimation and practical channel estimation in low-to-medium mobile speed and compare them with conventional OFDM/QAM system. Simulation results show that OFDM/OQAM-IOTA system with proposed preamble structure has 1.5 dB Eb/NO gain on Target BER $10^{-3}$ and about $25\%$ transmission rate gain against the conventional OFDM/QAM system considering quarter of FFT size as guard interval size.