Results 111 to 120 of about 123,247 (141)

Apodized adaptive beamformer

Journal of Medical Ultrasonics, 2017
A number of studies aimed at improvement of ultrasound image quality, such as spatial resolution and contrast, have been conducted. Apodization is known as an important factor that determines image quality. However, in the case of amplitude and phase estimation (APES) beamforming, a kind of adaptive beamformer that has been employed in medical ...
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Adaptive monopulse beamforming [PDF]

Proceedings of the IEEE, 1976
A new receive-array adaptive beamformer configuration is presented. The array output signal consists of the difference between a conventionally weighted beam and an adaptive beam that is constrained to have a spatial null in the direction of interest. Adaptation then provides minimum total array output power.
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Adaptive Beamforming and Postfiltering

2008
In this chapter, we explore many of the basic concepts of array processing with an emphasis on adaptive beamforming for speech enhancement applications. We begin in Sect. 47.1 by formulating the problem of microphone array in a noisy and reverberant environment. In Sect.
Israel Cohen, Sharon Gannot
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Adaptive-adaptive subarray narrowband beamforming

IEEE International Conference on Acoustics Speech and Signal Processing, 1993
A two-stage adaptive narrowband beamformer is introduced. Adaptive beamformers give high-resolution angle-of-arrival estimates, but at considerable computational cost. To reduce the computational cost, N. Owsley and D. Abraham (1989) have introduced a two-stage beamformer-conventional first-stage, adaptive second-stage-which gives near full adaptive ...
J.A. Nuttall, Peter Willett
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Multichannel Adaptive Beamforming

2004
Multiantenna transceivers have received a considerable attention when developing next generation wireless communication systems. In this chapter we discuss different alternatives of utilizing multiple antennas in commercial wireless communication systems. By multichannel adaptive beamforming we understand a concept where the receiver estimates multiple
Timo Korhonen, Jyri Hamalainen, Risto Wichman   +2 more
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Robust Adaptive Beamforming

2009
In this chapter, we first review the background, basic principle and structure of adaptive beamformers. Since there are many robust adaptive beamforming methods proposed in literature, for easy understanding, we organize them into two categories from the mathematical point of view: one is based on quadratic optimization with linear and nonlinear ...
Zhu Liang Yu, Meng Hwa Er, Wee Ser, Chen Huawei   +3 more
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Adaptive beamforming for Doppler signal

2001 CIE International Conference on Radar Proceedings (Cat No.01TH8559), 2002
A small number of samples and system errors can degrade the performance of adaptive arrays, particularly when the input signal-to-noise ratio (SNR) is large. A direct signal cancellation method to estimate the interference-noise covariance matrix which increases the SINR by using the desired signal Doppler information is proposed. It has the advantages
Zhang Linrang, Liao Gui-sheng, Bao Zheng
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Robust Adaptive Beamforming

2001
This chapter presents robust adaptive beamforming techniques designed specifically for microphone array applications. The basics of adaptive beamformers are first reviewed with the Griffiths-Jim beamformer (GJBF). Its robustness problems caused by steering vector errors are then discussed with some conventionally proposed robust beamformers.
Osamu Hoshuyama, Akihiko Sugiyama
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Adaptive Beamforming Assisted ReceiverAdaptive Beamforming

2009
Adaptive beamforming is capable of separating user signals transmitted on the same carrier frequency, and thus provides a practical means of supporting multiusers in a space-division multiple-access scenario. Moreover, for the sake of further improving the achievable bandwidth efficiency, high-throughput quadrature amplitude modulation (QAM) schemes ...
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Research on adaptive beamforming algorithm

2012 International Conference on Image Analysis and Signal Processing, 2012
Adaptive beamforming is a key technology of smart antenna; the core is to obtain the optimum weights of the antenna array by some adaptive beamforming algorithms, and finally adjust the main lobe to focus on the arriving direction of the desired signal, as well as suppress the interfering signal.
Qiu Dong-dong, Darwin R. Becerra, Rao Jia-ren, Zong Peng, Sun Yong-jiang   +4 more
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