Harris, P M; Lord, G J; Smith, I M; Robinson, S P (2001) The application of wavelets and other techniques to the calibration of underwater electroacoustic transducers in reverberant laboratory tanks. NPL Report. CMSC 11/01

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Abstract

In the calibration of underwater electracoustic transducers undertaken in reverberant laboratory tanks, data processing is used to extract from the measured data the required information for the calibration. This information is the voltage that would be measured in the absence of contaminating effects, including transients due to the resonance of the devices, reflections of the transmitted signal, and noise.
There are a number of approaches to performing the data analysis currently in use, including the application of signal processing techniques based on Fourier analysis as well as regression modelling. Wavelet analysis provides another approach to analysing spectrally varying sequences of data that complements the traditional Fourier analysis. Wavelets provide a general set of basis functions that are localised both in time and frequency, and wavelet analysis has been applied successfully to problems in feature recognition, signal compression, function representation and as a basis for numerical schemes. The coefficients obtained in a wavelet expansion are useful as they relate directly to a time (or place) and frequency, and to the smoothness of the signal.
In this report we provide a summary of some of the 'traditional' data analysis methods used for the calibration of underwater electroacoustic transducers, and indicate some of their limitations. We then give a brief introduction to wavelet analysis, and consider how methods of analysis based on wavelets can be applied to this particular measurement problem. The intention here is to consider how wavelet analysis may support and complement the 'traditional' methods of analysis by addressing some of the limitations of those methods.

Item Type:	Report/Guide (NPL Report)
NPL Report No.:	CMSC 11/01
Keywords:	wavelets, electroacoustics, calibration
Subjects:	Mathematics and Scientific Computing Mathematics and Scientific Computing > Modelling
Last Modified:	02 Feb 2018 13:17
URI:	http://eprintspublications.npl.co.uk/id/eprint/2436

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