• 전기의세계
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• 제29권9호
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• pp.584-593
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• 1980

Conventional radar antenna systems are susceptible to performance degradation caused by unwanted signals received via the antenna sidelobes and/or mainlobes. Adaptive array systems offer possible solution to this interference problem by automatically steering nulls to unwanted signals providing significant system performance improvement. Another important andvantage of the adaptive array is its self-optimization capability which uses the collective incoming noise data for the nulling purposes. This paper provides a tutorial introduction to adaptive arrays as well as some new development of recent research in this area. Optimum link between the antenna theory and signal processing has been sought by illustrating the gain patterns and output signal-to-noise ratio. Signal acqusition methods are shown including a new attempt of the use of spread-spectrum techniques in conjuction with array systems.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권2호
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• pp.155-167
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• 2015

An adaptive equalization scheme based on all-digital jitter measurement is proposed for a continuous time linear equalizer (CTLE) preceding a clock and data recovery (CDR) in a receiver circuit for high-speed serial interface. The optimum equalization coefficient of CTLE is determined during the initial training period based on the measured jitter. The proposed circuit finds automatically the optimum equalization coefficient for CTLE with 20", 30", 40" FR4 channel at the data rate of 5 Gbps. The chip area of the equalizer including the adaptive controller is 0.14 mm2 in a $0.13{\mu}m$ process. The equalizer consumes 12 mW at 1.2 V supply during the normal operation. The adaptive equalizer has been applied to a USB3.0 receiver.

• 한국군사과학기술학회지
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• 제16권3호
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• pp.382-389
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• 2013

In anti-jamming GPS receiver, adaptive signal processing techniques in which the radiation pattern of adaptive array antenna of elements may be adaptively changed used to reject interference, clutter, and jamming signals. In this paper, I describes adaptive signal processing technique using the sample matrix inversion(SMI) algorithm. This adaptive signal processing technique can be applied effectively to wideband/narrowband anti-jamming GPS receiver because it does not consider the satellite signal directions and GPS signal power level exists below the thermal noise. I also analyzed the effects of covariance matrix sample size and diagonal loading technique on the system performance of five-element circular array antenna. To attain near optimum performance, more samples required for calculation covariance matrix. Diagonal loading technique reduces the system nulling capability against low-power jamming signals, but this technique improves robustness of adaptive array antenna.

• 디지털산업정보학회논문지
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• 제10권4호
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• pp.71-78
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• 2014

Method a target estimation in spatial are mobile wireless communication using network cell and GPS. It have much error that mobile wireless communication depend on cell size. GPS method can't find a target in shadow and inner area. In this paper, we estimate a target as direction of arrival method using adaptive array antenna system. Adaptive array antenna system can obtain desired signal to remove other signal This paper studied digital beamforming method in order to estimation a target. Proposed method is modified optimum weight and antenna error correction to estimation an optimal receive signal. Digital beamforming method decided a signal phase and amplitude from received signal on array antenna element. But if it is not to do error correction of received signal, system performance have decreased. Firstly, we proposed modified optimum weight in order to finding desired target. Secondly, we are error correction of antenna incident signals by optimal weight before digital beamforming method. Thirdly, throughly simulation, we showed that system performance of proposed method compare proposal method with general method. It have improved resolution of estimation target to good performance more proposed method than general method.

• 디지털산업정보학회논문지
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• 제10권4호
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• pp.63-70
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• 2014

Method a target estimation in spatial are mobile wireless communication using network cell and GPS. It have much error that mobile wireless communication depend on cell size. GPS method can't find a target in shadow and inner area. In this paper, we estimate a target as direction of arrival method using adaptive array antenna system. Adaptive array antenna system can obtain desired signal to remove other signal This paper studied digital beamforming method in order to estimation a target. Proposed method is modified optimum weight and antenna error correction to estimation an optimal receive signal. Digital beamforming method decided a signal phase and amplitude from received signal on array antenna element. But if it is not to do error correction of received signal, system performance have decreased. Firstly, we proposed modified optimum weight in order to finding desired target. Secondly, we are error correction of antenna incident signals by optimal weight before digital beamforming method. Thirdly, throughly simulation, we showed that system performance of proposed method compare proposal method with general method. It have improved resolution of estimation target to good performance more proposed method than general method.

• Journal of information and communication convergence engineering
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• 제12권3호
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• pp.140-144
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• 2014

A general linearly constrained adaptive array is examined in the weight vector space to illustrate the array performance with respect to the gain factor. A narrowband linear adaptive array is implemented in a coherent signal environment. It is shown that the gain factor in the general linearly constrained adaptive array has an effect on the linear constraint gain of the conventional linearly constrained adaptive array. It is observed that a variation of the gain factor of the general linearly constrained adaptive array results in a variation of the distance between the constraint plane and the origin in the translated weight vector space. Simulation results are shown to demonstrate the effect of the gain factor on the nulling performance.

• 전기전자학회논문지
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• 제17권2호
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• pp.111-118
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• 2013

본 논문에서는 부대역 신호를 사용한 병렬 적응 비선형 Volterra 필터를 소개하고, 이 시스템의 성능을 분석하는 것을 주요 내용으로 한다. 연구 결과 제시한 부대역 신호를 사용한 적응 Volterra 필터는 수렴성이 우수함을 입력신호의 상관함수의 eigenvalue 분포를 사용하여 해석적으로 도출되었으며, 이러한 응용이 최근에 보고된 적응 반향 제거기에서 유용하게 사용될 수 있음을 이론적으로 밝혔다. 또한 각 부대역 에서의 최적필터를 이론적으로 유도하였고 컴퓨터 모의실험으로 이를 검증하였다.

• 한국음향학회지
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• 제13권4호
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• pp.77-85
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• 1994

본 연구에서는 필터의 차수가 적절한 수준으로 자동적으로 조정되는, 최적 수렴 인자를 갖는 최대 경사 (steepest descent) 방식의 적응 알고리듬을 제안한다. 지금까지 적응 신호 처리의 여러 응용 분야에 적응 필터를 사용할 때, 사전 지식이나 경험에 비추어 필터 차수를 고정하여 이용하여 왔다. 하지만 실제 실행시 필요한 필터 차수를 알기는 어렵고 되도록 큰 차수의 필터를 실행해야만 한다. 이로 인하여 필터 차수가 너무 큰 경우 필요없는 계산량이 증가하게 된다. 제안한 가변 길이 최적 수렴 인자 알고리듬은 주어진 차수 한도 내에서 자동적으로 적절한 절터 차수를 찾아 동작하므로, 불필요한 계산량의 증가를 줄여서 결과적으로 수렴 속도의 향상과 정상 상태에서의 수렴 오차를 줄일 수 있다. 제안한 알고리듬의 타당성은 시스템 식별에 대한 컴퓨터 모의 실험으로 입증하였다.

• 한국산업융합학회 논문집
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• 제23권5호
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• pp.799-807
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• 2020

This paper deals with identification of probabilistic design using reliability based robust optimization in structure design of automatic salt collector. The thickness sizing variables of main structure member in the automatic salt collector were considered the random design variables including the uncertainty of corrosion that would be an inevitable hazardousness in the saltern work environment. The probabilistic constraint functions were selected from the strength performances of the automatic salt collector. The reliability based robust optimum design problem was formulated such that the random design variables were determined by minimizing the weight of the automatic salt collector subject to the probabilistic strength performance constraints evaluating from reliability analysis. Mean value reliability method and adaptive importance sampling method were applied to the reliability evaluation in the reliability based robust optimization. The three sigma level quality was considered robustness in side constraints. The probabilistic optimum design results according to the reliability analysis methods were compared to deterministic optimum design results. The reliability based robust optimization using the mean value reliability method showed the most rational results for the probabilistic optimum structure design of the automatic salt collector.

• 한국음향학회지
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• 제36권3호
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• pp.151-157
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• 2017

잡음신호제거 성능을 향상시키기 위하여 일반선형제약적응배열이 제안되었다. 잡음신호제거 성능이 배열계수 벡터공간에서 검토되었다. 제약면이 이득요소에 의하여 원점에 대하여 수직 방향으로 이동하는데 이득요소가 커지면 원점과의 거리는 감소하게 됨이 밝혀졌다. 따라서 이득요소의 변화가 계수벡터와 잡음신호 방향벡터와의 직교성의 정도에 영향을 주어서 일반선형제약적응배열의 잡음신호제거 성능이 이득요소에 의하여 향상되게 된다. 제안된 적응 배열은 최적의 이득요소 수치에서 간섭적인 신호환경에서는 기존의 선형제약적응배열에 비하여 더 나은 잡음신호제거 성능을 나타내고 비간섭적인 신호환경에서는 비슷한 잡음신호제거 성능을 나타냄이 관찰되었다.