• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.11a
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• pp.1-3
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• 2010

본 논문에서는 VSB 수신기를 위한 반송파 위상 오차에 독립적인 심벌 타이밍 옵셋 추정 알고리즘을 제안하고자 한다. 심벌 타이밍 옵셋 추정에 대표적인 알고리즘인 가드너 방법은 반송파 위상 옵셋이 포함된 VSB 수신기에서는 타이밍 옵셋을 추정할 수 없다. 본 논문에서는 수신신호의 공액 곱 연산을 통하여 신호의 스펙트럼을 확장하고 반송파 위상 옵셋을 상쇄 하였고, 그 후 가드너 알고리즘을 통하여 인접 스펙트럼 간의 중복부분을 발생시켜, 타이밍 옵셋을 추정하는 방식을 연구하였다. 시뮬레이션 결과, 제안하는 알고리즘은 VSB 수신기에서 반송파 위상 오차에 영향을 받지 않고, 정확하게 타이밍 옵셋을 추정할 수 있는 것으로 나타났다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.3
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• pp.25-32
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• 2004

An advanced algorithm for measurement of phase angle between two sinusoidal signals is proposed in this paper. This algorithm uses discrete sample data of two input signals for calculation of phase angle and amplitude. And the key parameters of the measurement algorithm are described by analytical express, so the calculation of phase angle is simplified. In this paper it is proved that harmonic distortion of the input sinusoidal signals does not affect the measurement value of phase angle by using the proposed algorithm when a whole cycle is sampled. And measurement error by the white Gaussian noise is very small compared by other algorithms.

• Journal of the Korea Convergence Society
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• v.6 no.5
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• pp.249-255
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• 2015

In this paper, we present an azimuth error analysis for the correlative interferometer direction finding. The correlative interferometer is a direction finding method that compares the theoretical and measured phase differences. The direction of the radio transmitter can be estimated by obtaining the maximum correlation between two data sets. We used a 5-element circular array antennas arranged in a circle. To derive the correlation function between antenna elements, we assume that the incident plane wave arrives from a certain angle and the phase difference of each antenna can be derived by comparing with the reference. The suggested direction finding gives a relatively accurate result even if the radio transmitter is located in the higher altitude.

• Korean Journal of Optics and Photonics
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• v.22 no.5
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• pp.207-213
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• 2011

We propose a new method to measure the phase errors of an AWG(arrayed waveguide grating) through Monte-Carlo analysis. In the frequency domain method, we used the Monte-Carlo method to fit the theory to the experimental results. The phase and amplitude values are obtained from the fitted theory. To verify our method, we carried out a simulation. Some phase errors were included to make a virtual interferogram and we measured the actual AWG phase errors from it by our method. The results show that our method gives good results if the laser tuning range is larger than 1.7 times of the AWG FSR(free spectral range) and if the phase errors are within ${\pm}50^{\circ}$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.11
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• pp.828-833
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• 2018

It is well known that reflected waves and resonance affect phase distortion. In addition, phase delay can be distorted by antenna impedance. In this study, we analyze the phase delay variation caused by the antenna impedance, considering mutual coupling effects. In addition, we confirm the beam steering characteristics. When was -10 dB and -7 dB, the maximum phase delay error was $18.5^{\circ}$ and $26.5^{\circ}$, respectively. The Monte Carlo simulation with an eight-element linear array antenna demonstrated that the RMS error of the beam steering angle ranged from $0.19^{\circ}$ to $0.4^{\circ}$, and the standard deviation ranged from $0.14^{\circ}$ to $0.33^{\circ}$ when the beam steering angle was in the range of $0^{\circ}$ to $30^{\circ}$, with the uniformly distributed phase error of $18.5^{\circ}$ and $26.5^{\circ}$. The side lobe level increased from 0.74 dB to 1.21 dB by the phase error from the theoretical value of -12.8 dB, with a standard deviation of 0.31 dB to 0.51 dB. This is verified by designing an eight-element spiral array antenna.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.209-209
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• 2018

국토교통부는 대하천에서의 홍수 감시를 위해 전국에 6기의 강우레이더를 도입 완료하였다. 비슬산레이더는 2009년에 맨 먼저 도입된 강우레이더로 국내 최초로 도입된 이중편파 S밴드 레이더이다. 이중편파레이더는 반사도 외에도 차등반사도, 차등위상차, 비차등위상차 등 다양한 레이더 편파변수들을 제공하고 있다. 이중 반사도, 차등반사도, 비차등위상차는 레이더 강수량 추정에 적용되는 편파변수들로 이 변수들에 오차가 내재 시 레이더 강우의 오차에 전파되게 된다. 이에 레이더 강우 추정에 적용되는 편파변수들에 내재되어 있는 오차를 정량화하고 제거하는 것은 레이더 강우 품질에 직결되는 문제이다. 본 연구에서는 2009년부터 2016년까지의 비슬산레이더로부터 관측된 총 351개의 강수사례를 수집하여 레이더 반사도와 차등반사도의 오차를 정량화 하였다. 그리고 이러한 편파변수들의 오차 제거시 레이더 강우량의 정확도가 어느 정도 향상되는 지를 확인하였다. 그 결과 레이더 강우량의 정확도는 편파변수 오차 제거 전에는 40 ~ 80% 범위에서 오차제거 후 60 ~ 80 % 범위로 정확도가 향상되었고 그 범위도 줄어들었다.

• Bulletin of the Korean Space Science Society
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• 2004.04a
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• pp.44-44
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• 2004

GPS를 이용하여 대기 수증기의 3차원 분포도를 구하기 위하여, 관측소와 GPS 위성 간 시선방향으로의 수증기에 의한 GPS 신호지연 정도를 결정할 필요가 있다. 이 때 정확성 향상을 위하여 반드시 고려해야하는 위상중심변화(phase center variations)와 조석하중에 의한 지각변위(ocean loading displacements) 등 수직방향 좌표 결정 오차를 유발하는 요인들을 소개한다. 타 연구를 통해 위상중심변화는 크게는 l0cm 이상의 오차를, 그리고 조석하중에 의한 지각변위는 한반도의 경우 최대 3-4cm 정도의 오차를 보임을 알았지만, 이들 오차가 시선방향 습윤지연 결정에 미치는 영향은 규명되지 않았다. (중략)

• Korean Journal of Optics and Photonics
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• v.13 no.1
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• pp.38-43
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• 2002

Simple principles of self-imaging in Multi-Mode Interference (MMI) devices are based on the approximation of propagation constants. The analysis of the basic nature of the self-imaging principle reveals the problems of previous optimization methods, and provides a new scheme to optimize the external variables for the reconciliation of approximation problems by considering two different tendencies of approximation effects. Furthermore, the representative mode method is proposed to make the application easy. This optimization method provides an essential method for stable design and fabrication of MMI devices with improved characteristics.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.3
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• pp.149-155
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• 2019

In this paper, phase shifter has been designed and manufactured to apply to passive phase array seeker for Ka-band and its performance was confirmed. It was designed as a key element for conducting electric beam steering by adjusting the phase of the array element. Insertion loss of less than 1.5dB and phase accuracy of less than $10^{\circ}$(RMS) in operation bandwidth of 1GHz were checked. The performance identified by the actual fabrication was further analyzed by applying the beam pattern analysis based on the array synthesis theory. The effect of the final performamnce of the proven phase shifter on the performance and pointing error and angular accuracy of the passive phase array antenna beam pattern was analyzed. Then, the validation of the proposed phase shifter has been made.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.1
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• pp.7-13
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• 2021

This paper proposes a method to minimize the target's direction detection error using RADAR. The radar system cannot accurately detect the target direction due to the phase error of he received signal. The proposed method of this study obtains a phase by applying an root mean square to each antenna incident signal, and reduces the phase error by using an optimal signal to noise ratio. In the simulation result, the probability of detecting the target direction is the best when the antenna spacing is half wavelength. The conventional method of direction detection probability 10-1.7 and the proposed method is 10-3.3. The target detection direction of the existing method represents [-8°,8°] with an error of 2 degrees. The target detection direction of the proposed method is shown in [-10°,10°], and all target directions are accurately detected. In the future, There is need for a method to reduce the phase error even though the resolution decrease.