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公开(公告)号：US5515060A
公开(公告)日：1996-05-07
申请号：US439541
申请日：1995-05-11
申请人： Moayyed A. Hussain , Kai-Bor Yu , Koeunyi Bae
发明人： Moayyed A. Hussain , Kai-Bor Yu , Koeunyi Bae
摘要： An active array antenna for use, for example, in a radar system, includes elemental antennas, each with a T/R module, distributed over a circular aperture. For lowest cost, the aperture is thinned. The T/R modules are operated at maximum output, to achieve maximum DC-to-RF efficiency, and for simplicity. A phase controller controls the phase shift which is imparted by each module to its signal, to form a main beam and its associated sidelobes. A perturbation phase generator portion of a phase controller adds a perturbation phase shift selected, in conjunction with a particular thinning distribution, to form a relatively wide null in the sidelobe structure, in which signal transduction is reduced. In a radar context, this null may be placed on a source of ground clutter or a jammer.
摘要翻译： 用于例如在雷达系统中的有源阵列天线包括分布在圆形孔径上的元素天线，每个天线具有T / R模块。 为了降低成本，孔径变薄。 T / R模块以最大输出运行，以实现最大的DC到RF效率，并为简单起见。 相位控制器控制由每个模块向其信号施加的相移，以形成主光束及其相关的旁瓣。 相位控制器的扰动相位发生器部分将选择的扰动相位与特定的稀疏分布相结合，以在信号转导减小的旁瓣结构中形成相对较宽的零点。 在雷达环境中，这个零点可能被放置在地面杂波或干扰源上。
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公开(公告)号：US5274384A
公开(公告)日：1993-12-28
申请号：US997470
申请日：1992-12-28
申请人： Moayyed A. Hussain , Kai-Bor Yu , David J. Murrow
发明人： Moayyed A. Hussain , Kai-Bor Yu , David J. Murrow
摘要： An antenna beamformer is provided for coupling to a circular antenna aperture comprising a plurality of vertical beamformers and four horizontal beamformers coupled to the vertical beamformers so that each horizontal beamformer has the capability to form a different predetermined electromagnetic field radiation pattern.
摘要翻译： 提供天线波束形成器用于耦合到圆形天线孔径，其包括多个垂直波束形成器和耦合到垂直波束形成器的四个水平波束形成器，使得每个水平波束形成器具有形成不同的预定电磁场辐射图案的能力。
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公开(公告)号：US4646024A
公开(公告)日：1987-02-24
申请号：US548174
申请日：1983-11-02
CPC分类号： H01F7/20 , H01F41/045 , Y10S505/844
摘要： In the production of nuclear magnetic resonance images, it is necessary to provide various magnetic fields with specified orientations and configurations in particular relationships with respect to a cylindrical coil form on which the RF and gradient coils are generally disposed. In particular, it is necessary to produce so-called transverse gradient fields which are oriented transversely with respect to the cylindrical form. It is necessary to produce a component parallel to the axis of the cylinder, but which component varies linearly in intensity in the direction transverse to the axis. That is to say, it is desirable to produce a magnetic field component within the cylinder such that surfaces on which this component is constant are parallel and are generally oriented parallel to the axis of the cylinder. Furthermore, for the purpose of providing proper spatial definition and resolution, it is necessary that this transverse field exhibit a highly linear variation in intensity inside the cylinder. In a nuclear magnetic resonance imaging system, two such coil sets are required and are oriented at right angles to one another so as to generate x-axis and y-axis positioning information. The present invention describes coil winding patterns which are capable of producing such transverse gradient magnetic fields with an exceedingly high degree of linearity.
摘要翻译： 在生产核磁共振图像时，有必要提供具有指定取向和配置的各种磁场，这些磁场与通常设置有RF和梯度线圈的圆柱形线圈形式有关。 特别地，有必要产生相对于圆柱形横向定向的所谓的横向梯度场。 需要产生平行于圆柱体轴线的分量，但哪个分量在横向于轴线的方向上强度线性变化。 也就是说，期望在圆柱体内产生磁场分量，使得该部件恒定的表面是平行的，并且大致定向为平行于圆柱体的轴线。 此外，为了提供适当的空间定义和分辨率，有必要使该横向场在气缸内呈现高度线性的强度变化。 在核磁共振成像系统中，需要两个这样的线圈组，并且彼此成直角定向，以便产生x轴和y轴定位信息。 本发明描述了能够产生具有非常高的线性度的这种横向梯度磁场的线圈绕组图案。
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公开(公告)号：US08818746B1
公开(公告)日：2014-08-26
申请号：US13071691
申请日：2011-03-25
IPC分类号： G01R23/16 , G01N29/04 , G01N29/14 , G01N29/46 , G01N21/952
CPC分类号： G01N29/045 , G01N21/952 , G01N29/14 , G01N29/46 , G01N2203/006
摘要： A simple, inexpensive, and fast method of establishing if a defect does or does not exist within a thick-walled solid geometry, which is especially useful to detect if such a defect, a crack, exists within a gun barrel. With further analysis, the method allows not only the identification of the defect's presence; but, a means of establishing the size thereof—which, for example, is critical to understanding if a gun tube has a defect that would warrant its being taken out of service for the safety of its crew or removed from manufacturing. The method involves creating an acoustic vibration in the particular thick-walled, solid geometry, esp. a gun barrel, and observing the vibration pattern which results. The size of the particular defect can be ascertained by a) manually using a correlation between the magnitude of the defect and the relative changes in the decay coefficient or shifts in frequency data or (b) automatically using a Bayes maximum likelihood, statistical pattern classification algorithm and a library comprised of either the decay coefficients or the means and covariances of defect-free and cracked objects.
摘要翻译： 一种简单，便宜和快速的方法来确定缺陷是否存在于厚壁实心几何中，特别适用于检测枪管内是否存在这样的缺陷，裂纹。 进一步分析，该方法不仅可以识别缺陷的存在; 而是确定其尺寸的一种手段，例如，这对于了解枪管是否具有缺陷，对于其船员的安全性或从制造中移除而导致的缺陷是非常关键的。 该方法涉及在特定的厚壁实心几何中产生声振动，尤其是。 一个枪管，并观察结果的振动模式。 特定缺陷的大小可以通过以下方式来确定：a）手动使用缺陷的大小与衰减系数的相对变化或频率数据的偏移之间的相关性，或（b）自动使用贝叶斯最大似然度统计模式分类算法 以及由无缺陷和破裂的物体的衰变系数或平均值和协方差组成的图书馆。
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公开(公告)号：US5302961A
公开(公告)日：1994-04-12
申请号：US997466
申请日：1992-12-28
申请人： David J. Murrow , Kai-Bor Yu , Moayyed A. Hussain
发明人： David J. Murrow , Kai-Bor Yu , Moayyed A. Hussain
CPC分类号： G01S7/36 , G01S7/2813 , H01Q25/02
摘要： A nonrectangular antenna aperture is provided comprising four quadrants for receiving electromagnetic signals. The aperture has the capability to form a predetermined sum beam, a predetermined first difference beam, a predetermined second difference beam, and a predetermined double difference beam so that the product of the first and second difference beams is substantially equal to the product of the sum and the double difference beams.
摘要翻译： 提供了一个非矩形天线孔径，包括用于接收电磁信号的四个象限。 孔径具有形成预定和波束，预定第一差分光束，预定第二差分光束和预定双差分光束的能力，使得第一和第二差分光束的乘积基本上等于总和的乘积 和双差分光束。
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公开(公告)号：US5548561A
公开(公告)日：1996-08-20
申请号：US395143
申请日：1995-02-27
CPC分类号： G10K11/345 , G01S7/52046 , G01S15/8918 , G01S7/52023 , G01S7/52033
摘要： In a digital ultrasound imaging system, artifacts due to spurious ultrasound reflections from a highly reflective object outside the region of interest are reduced in magnitude by apparatus included in the beamforming system of the digital imaging system. A null is formed in a specified direction in the ultrasound beam patterns by perturbing the time delay on each receive channel. After estimating the direction of the highly reflective, interfering object and computing a time delay perturbation using a very fast algorithm, a null approximately 10 dB deep is introduced into each beam in the direction of the interfering object. This null reduces the magnitude of artifacts in the image, thereby providing image enhancement.
摘要翻译： 在数字超声成像系统中，通过包括在数字成像系统的波束成形系统中的设备，由于来自感兴趣区域外的高反射物体的伪超声反射造成的伪影的幅度被减小。 通过扰乱每个接收通道上的时间延迟，在超声波束图案中在指定方向上形成零点。 在估计高反射性干扰对象的方向并使用非常快的算法计算时间延迟扰动之后，在干扰对象的方向上将每个波束中的大约10dB的零空间引入。 该零减少了图像中的伪影的大小，从而提供图像增强。
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