Accession Number : ADA055600


Title :   SUS Source Level Error Analysis


Descriptive Note : Final rept.


Corporate Author : UNDERWATER SYSTEMS INC ROCKVILLE MD


Personal Author(s) : Holmer, Curtis I


Full Text : http://www.dtic.mil/dtic/tr/fulltext/u2/a055600.pdf


Report Date : 20 Jan 1978


Pagination or Media Count : 159


Abstract : The report provides an analysis of major terms which contribute to signal analysis error in a proposed experiment to calibrate source levels of SUS (Signal Underwater Sound). A unique model of the digital signal analysis process was used to verify and empirically extend the results of analytic studies. The analytic findings indicate that the discrete Fourier transform, without windowing, is error free when the signal is adequately anti-alias filtered, and wholly contained in the analysis time window. The model was used to generate exact spectra for comparison with digitally analyzed spectra. Errors due to FFT roundoff, aliasing, quantization and registration were studied to verify error expressions and to identify empirical error bounds. Discrete amplitude representation (quantization) was found to introduce systematic error at low frequencies, for the particular time series that were studied, when insufficient resolution was provided.


Descriptors :   *TRANSDUCERS , *CALIBRATION , *UNDERWATER SOUND SIGNALS , COMPUTER PROGRAMS , SIGNAL PROCESSING , COMPUTERIZED SIMULATION , DIGITAL SYSTEMS , SPECTRUM ANALYSIS , CLIPPER CIRCUITS , DISCRETE FOURIER TRANSFORMS , NOISE REDUCTION , TIME SERIES ANALYSIS , ACCURACY , ERROR ANALYSIS , FAST FOURIER TRANSFORMS


Subject Categories : Acoustic Detection and Detectors


Distribution Statement : APPROVED FOR PUBLIC RELEASE