【摘要】 为解决烟机振动信号受到噪声干扰这一问题,研究基于小波包阈值降噪的原理和方法,给出了小波包阈值降噪的步骤,阐述了Birgé-Massart惩罚函数确定阈值的原则和软阈值的量化处理,分析了阈值、信噪比和均方误差随惩罚因子的变化规律.并将基于小波包惩罚函数的软阈值降噪与Rigrsure、Heursure、Sqtwolog、Minimax4种阈值降噪方法进行了比较.结果表明基于惩罚函数的小波包软阈值方法能有效降低噪声.基于该方法的烟机振动信号降噪在保留信号突变部分的同时,具有良好的光滑性.更多还原

【Abstract】 To solve the problem of vibration signals acquired from flue gas turbine interfered by noise,the principle and method of wavelet packet-based penalty function soft-threshold denoising are analyzed and its procedure of de-noising is provided.The rule of Birgé-Massart penalty function to determine threshold is clarified and soft-threshold quantization processing is made.Then,the value changes of threshold,SNR and mean square error with the penalty factor are observed and compared with Rigrsure,Heursure,Sqtwolog,Minimax soft-threshold de-noising methods.The results show that the penalty function soft-threshold method can effectively reduce the noise.The de-noised vibration signals of flue gas turbine based on this method can retain mutant part of the signal ,while it still has good smoothness.更多还原