基于小波变换的内燃机瞬时转速信号的分析

Analysis on the transient speed signal of internal combustion engine based on wavelet transform

使用非线性离散序列的小波变换 (DTWT)对同时存在高频噪声和高斯白噪声的内燃机瞬时转速信号进行去噪 .通过对此信号进行频谱分布的分析 ,用Donoho的阈值去噪法去除高斯白噪声之后 ,根据小波变换的多分辨率思想 ,提出了仅使用小波变换的尺度系数进行小波反变换来去除高频噪声 ,然后运用小波反变换来恢复内燃机瞬时转速信号的方法 .实验结果表明 ,此方法能够较精确的去除噪声 ,恢复内燃机瞬时转速信号 .

The method of nonlinear DTWT is used to do denoising for the transient speed signals of internal combustion engine in which high frequency noises and Gaussian white noises exist simultaneously. Donoho's soft thresholding method is used to denoise the Gaussian whiue noises by analyzing the spectrum distribution of transient speed signal. A new method using only wavelet transform scale coefficients to reduce high frequency noises based on the wavelet transform's multi-resolution analysis theory is proposed. Experimental results show that the method can reduce the noises effectively and restore the transient speed signals of internal combustion engine.