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一、引言声全息是著名的全息处理的一个特殊情况,它的全息图由相干声波产生。一旦把全息信息复制成光全息图以后,物波就能够用相干光来重现。这个方法在水声技术中的特殊问题是把声信息转换成一张适合重现的全息图。为了能够获得所希望的高方位分辨率,必须使用大孔径。因而,接收水听器系统一定要由大量的离散元组成。另一方面,因为接收信号极弱,所以每个水听器后面必须跟着它自己的单独的放大器,以便把它们的输出电压放大到足够高的电平。由于这些原因,水声信号全息接收器变得非常庞大。比如一幅由100行和100
I. INTRODUCTION Acoustic holography is a special case of the well-known holographic processing of holograms generated by coherent sound waves. Once the holographic information is copied into a light hologram, the matter waves can be reproduced with coherent light. A particular problem with this method in acoustical technology is the conversion of acoustic information to a hologram suitable for reproduction. In order to achieve the desired high azimuth resolution, a large aperture must be used. Therefore, the receiving hydrophone system must be composed of a large number of discrete elements. On the other hand, because the received signal is very weak, each hydrophone must follow its own separate amplifier behind to amplify their output voltage to a sufficiently high level. For these reasons, the acoustic signal holographic receiver becomes very large. For example, a 100 line and 100