Analysis and application of modified methods of wavelet threshold functions

The signal of wind turbine in vibration and noise testing is often very weak, and it subject to a variety of noise interference in the course of its transmission. The signal with the acceleration sensor caught is often manifested as the signal with weak characteristics in the context of strong noise. In signal analysis, signal de-noising is an indispensable key link. This paper adopting the Donoho´s de-noising idea of wavelet threshold function, improve and deeply research the Wavelet Threshold Function on the basis of the classical soft and hard threshold de-noising function. The improved threshold function is applied to the diagnosis of the vibration noise of the wind turbine. The signal is analyzed and the product is improved accordingly. The result indicates that the improved threshold function has obvious de-noising effects in comparing with the traditional soft and hard threshold function.