• Title, Summary, Keyword: phase error

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System Phase Noise for Mobile Satellite Communication Service (이동형 위성통신 서비스를 위한 시스템 위상 잡음)

  • Kim Young-wan
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.9 no.8
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    • pp.1780-1786
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    • 2005
  • The phase error generated in the transmission system affects the performance of digital transmission signal. The phase error are generated by random phase noise and tracking phase error due to denier phenomenon. In the mobile satellite communication system that generates the doppler frequency, which is a system with a movement, the proper system phase noise spectrum should be designed based on analyses for phase noise and static phase error effects. Based on the analyses of the doppler frequency and the phase error for bilateral satellite communication system providing an asynchronous service, the phase noise spectrums for the mobile satellite communication are designed in this paper. Also, the available transmission services under the less doppler effect are proposed and the proper signal source units for a required transmission system can be designed under the proposed system phase noise spectrum.

2-step Phase-shifting Digital Holographic Optical Encryption and Error Analysis

  • Jeon, Seok-Hee;Gil, Sang-Keun
    • Journal of the Optical Society of Korea
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    • v.15 no.3
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    • pp.244-251
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    • 2011
  • We propose a new 2-step phase-shifting digital holographic optical encryption technique and analyze tolerance error for this cipher system. 2-step phase-shifting digital holograms are acquired by moving the PZT mirror with phase step of 0 or ${\pi}$/2 in the reference beam path of the Mach-Zehnder type interferometer. Digital hologram with the encrypted information is Fourier transform hologram and is recorded on CCD camera with 256 gray-level quantized intensities. The decryption performance of binary bit data and image data is analyzed by considering error factors. One of the most important errors is quantization error in detecting the digital hologram intensity on CCD. The more the number of quantization error pixels and the variation of gray-level increase, the more the number of error bits increases for decryption. Computer experiments show the results to be carried out encryption and decryption with the proposed method and the graph to analyze the tolerance of the quantization error in the system.

Evaluation Technique of Linearity of Ratio Error and Phase Angle Error of Voltage Transformer Comparison Measurement Equipment (전압변성기 비교 측정 장치의 비오차 및 위상각 오차의 직선성 평가기술)

  • 정재갑;박영태;권성원
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.53 no.9
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    • pp.470-474
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    • 2004
  • Both ratio error and phase angle error in voltage transformer(VT) depend on values of burden of VT used. A method of evaluation for linearity of ratio error and phase angle error in VT measurement equipment have been developed using the standard resistance burdens, with negligible AC-DC resistance difference less than $10^-6$. These burden consists of five standard resistors, with nominal resistance of 100 $\Omega$, 1 k$\Omega$, 10 k$\Omega$, 100 k$\Omega$, and 1 M$\Omega$. The developed method has been applied in VT measurement equipment of industry and the validity of the developed method has been verified by showing the consistency of the result of linearity obtained using VT with wide ratio error.

Effects of the Phase Error on the MTF Characteristics of Binary-phase Hologram Optical Low-pass Filter (컴퓨터로 설계한 2 위상 흘로그램 광 저대역 필터에서 위상차가 필터의 MTF 특성에 미치는 영향)

  • Go, Chun-Soo;Oh, Yong-Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.8
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    • pp.739-746
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    • 2005
  • When we design a binary phase holographic optical low-pass filter (HOLF), the phase difference is generally set to be $\pi$ to optimize the diffraction efficiency. However, the phase difference of real HOLF mostly deviate from $\pi$ by the error in the fabrication process. The deviation causes the (0,0)-th order diffracted beam to increase, which results In raising the diffraction efficiency. To study the effects of the phase error on the performance of HOLF, we calculated the MTF of HOLF for various phase differences. The results show that the phase error of 10 $\%$ makes little change in the filtering characteristics of HOLF. Considering the filtering by lens and CCD, the effects of the phase error becomes much smaller. To confirm it experimentally, we fabricated HOLFs for various phase differences. After installing it in a digital camera, we take picture of test targets and observe the Moire fringes and the resolution. The results agree with our prediction.

Measurement of Ratio Error/Phase Angle Error of Potential Transformer using High Voltage Capacitance Bridge and Uncertainty Analysis (고전압 전기용량 브리지를 이용한 전압변성기의 비오차와 위상각 오차의 측정과 불확도 분석)

  • Kwon, Sung-Won;Lee, Sang-Hwa;Kim, Myung-Soo;Jung, Jae-Kap
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.55 no.3
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    • pp.134-141
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    • 2006
  • A potential transformer(PT) has ratio error and phase angle error. Precise measurement of the errors of PT can be achieved using high voltage capacitance bridge, high voltage capacitor and low voltage capacitor. The uncertainty for this method is evaluated and found to be $20{\times}10^{-6}$ in both ratio error and phase angle error. The values measured for PT using the method are well consistent with the those measured for same PT in NMIA(National Measurement Institute of Australia) within the corresponding uncertainty.

RVDT Phase Error Compensation for Absolute Displacement Measurement (절대 변위 측정용 RVDT의 위상 오차 보상)

  • Shin Dong-Yun;Yang Yoon-Gi;Lee Chang-Su
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.7
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    • pp.658-665
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    • 2006
  • RVDT is a transducer that presents rotary phase angle according to the displacement of eccentric rotor such as press machine. However a study on the phase error of RVDT that affects precision is not enough. This paper analyzes RVDT phase error and obtains compensation curves with serial or parallel resistance through simulation. First, error compensation procedure that analyses errors due to the unbalance of reference inductances of each pole and uses parallel resistance as a compensation is proposed. Second, error compensation procedure due to the amplitude unbalance of the sensor driving currents is examined by serial compensation resistance. Experimentally, we got stable RVDT with phase error under $1^{\circ}$ by the proposed method.

Evaluation Technique for Ratio Error and Phase Displacement of Current Transformer Comparator (전류변성기 비교기의 비오차 및 위상오차 평가기술)

  • Kim, Yoon-Hyoung;Han, Sang-Gil;Jung, Jae-Kap;Han, Sang-Ok
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.57 no.4
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    • pp.437-443
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    • 2008
  • We have developed an evaluation technique for both ratio error and phase displacement of current transformer (CT) comparator by using the precise standard capacitors and resistors. By applying this technique to equivalent circuit of CT comparator evaluation system, we can obtain the calculated and measured ratio errors (or phase displacements) in the CT comparator. Thus we can evaluate ratio errors and phase displacement of CT comparator by comparing the calculated and measured ratio errors (or phase displacements). The method was applied to CT comparator under test with the ratio errors and phase displacement ranges of $0{\sim}{\pm}10%$ and $0{\sim}{\pm}7.5$ crad, respectively. Finally we have compared the ratio error and phase displacement of the CT comparator obtained in this method with specifications of two companies.

Performance Analysis of Frequency Offset Compensation and Tracking Algorithms for HDR-WPAN System (HDR-WPAN 시스템을 위한 주파수 옵셋 보상과 트래킹 알고리즘 성능분석)

  • Park, Ji-Woo;Oh, Chang-Heon
    • The Journal of Advanced Navigation Technology
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    • v.9 no.2
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    • pp.140-146
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    • 2005
  • In this paper, we proposed the frequency offset compensation algorithm and tracking algorithm which could improve the accumulated phase error for HDR-WPAN system. The proposed frequency offset compensation technique estimated each sample phase error by autocorrelation characteristics of CAZAC sequence, estimated phase error multiple each sample in a symbol, and finally compensated for the frequency offset. After frequency offset compensation using two steps, coarse and fine frequency offset, tracking algorithm have to use to compensate for the accumulated phase error. Because there is no pilot symbol in payload, more phase rotation occurred in received signal constellations due to the accumulated phase error as the payload length increase. Tracking algorithm compensates for a cumulative phase error ${\theta}$ between payload data.

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A Study on Ratio Error and Phase Angle Error Caused by an External Burden in Voltage Transformer (외부부담이 전압변성기의 비오차와 위상각오차에 미치는 영향에 대한 연구)

  • 정재갑;권성원;김규태;김명수
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.53 no.3
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    • pp.137-142
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    • 2004
  • A voltage transformer(VT) used for the estabilishment of high voltage national standard, has generally ratio error and phase angle error. Both errors in VT depend critically on values of external burden of VT used. Both ratio ewer and phase angle error in existence of the external burden is calculated. These calculated values are very well consistent with the experimental result. The principle and the measurement method of VT in our institute are also explained.

The design of phase error detector based on delayed n-tap rising edge clock:It's DP-PLL system application (지연된 n-탭 상승 에지 클럭을 이용한 위상 오차 검출기의 설계와 DP-PLL에의 적용)

  • 박군종;구광일;윤정현;윤대희;차일환
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.23 no.4
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    • pp.1100-1112
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    • 1998
  • In this paper, a novel method of minimizing the phase error is proposed. A DP-PLL system using this method is implemented and its performacnce is investigated, too. The DP-PLL system detects the phase error between reference clock and locally generated system clock. The phase difference is then reported as a PEV(Phase Error Variation), which is propoced from the delayted n-tap rising dege clock circuit with 5ns resolution in the phase detector. The algorithm is used to track the optimal DAC coefficients, which are adjusted from sample to sample in such a way as to minimize the PEV. The proposed method is found to have remarkable good potential for fast and accurate phase error tracking characteristic. The algorithm shows good performance to supress the low frequency jitter.-ending points, we design new basis functions based on the Legendre polynomial and then transform the error signals with them. When applied to synthetic images such as circles, ellipses and etc., the proposed method provides, in overall, outstanding results in respect to the transform coding gain compared with DCT and DST. And in the case when applied to natural images, the proposed method gives better image quality over DCT and comparable results with DST.

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