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METHOD FOR EVALUATING THE NUMBER propeller blades noisy SEA PROPERTY
METHOD FOR EVALUATING THE NUMBER propeller blades noisy SEA PROPERTY
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机译：螺旋桨叶片数噪声海的评估方法。
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摘要
1. A method of estimating the number of blades of the screw noisy object at sea, comprising: receiving object noisy sonar antenna signal; analog-to-digital conversion; bandpass filtering; calculation of the signal spectrum, characterized in that the spectrum found in the test signal frequency harmonic peak amplitude of f, assuming its main vane frequency scale f; predicting frequency rotary shaft scales f (i) = f / z (i), where z (i) = 3 ÷ 8 - hypotheses about the number of propeller blades noisy object; forming N reference spectra S (i) = cos (2πf · z (i) / f), where S (i) - a reference range for the hypothesis on the number of blades number i, comprising Valenod-blade scale, characteristic quantity z propeller blades ( i); is calculated for each S (i) its measure of similarity Kso spectrum of the signal; plotted by overlapping N pieces, each of which represents a built in polar coordinates graph of the function R (φ) = K (i) · cos (φ · z (i)) 'φ∈ (0,2π), and if the resulting figure is similar to the contour of screws z (i) blades, then conclude that the observed noisy object number of blades z (i) .2. A method according to claim 1, characterized in that the value of the similarity measure Kopredelyayut by the formula where F - spectrum of the signal.; S (i) - a reference range for the hypothesis number i; z (i) - a hypothesis about the number of propeller blades number i; A- the maximum amplitude of the harmonic spectrum.
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