Application of Acoustical Holography to Noise Data Analysis

  • W. S. Gan


A measure basic to nearly all noise data analysis works is filtering. Filtering is the extraction of useful information from data. Holography is information and so it can be used to extract certain information contained in a signal. Here we are interested to extract the repetitive or periodic signals from noise. The technique used is acoustical correlation filtering. We first record the periodic signal with a reference signal and this acoustical hologram is the complex filter function. The experimental method of recording the hologram follows that of Graham’s thesis. The filtered signal is the convolution of tie composite noise spectrum to be analyzed and the reconstruction from the holographic filter function. The next step is to obtain the reconstruction of the filter function in digital form. Digitization is done from the photographic form of the hologram. The digitized form serves as an input for the computer. The filtered signal then can be given as one output of the computer.


Free Vibration Periodic Signal Filter Function Noise Control Filter Signal 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. 1.
    W. S. Gan, “Application of Holography to Noise Source Identification,“ Proceedings of the 1974 International Conference on Noise Control Engineering, p. 113, Institute of Noise Control Engineering, U, S. A. (1974).Google Scholar
  2. 2.
    G. W. Stroke, An Introduction to Coherent Optics and Holography, Academic Press, Second Edition New York, (1969) p. 83–85.Google Scholar
  3. 3.
    T. Graham, Ph.D. Thesis (1969), “Long Wavelength Acoustic Holography“Google Scholar
  4. 4.
    R. L. Cohen and M S. Lang, to be published.Google Scholar
  5. 5.
    L. J. Cutrona, E. N. Leith, Z. J. Porcello, and C. J. Palermo; TIE Trans. Tnform. Theory, 6 386(1960).Google Scholar

Copyright information

© Springer Science+Business Media New York 1977

Authors and Affiliations

  • W. S. Gan
    • 1
  1. 1.Department of PhysicsNanyang Republic of UniversitySingapore 22Republic of Singapore

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