Which one is right about wavelet transforms? A: Wavelet transforms store large fractions of the strongest of the wavelet coefficients. B: Wavelet transforms are completely different from discrete Fourier transform (DFT). C: Each transform has 2 functions: smoothing, difference. D: Wavelet transforms means applying to pairs of data, resulting in two set of data of length L.

Which one is right about wavelet transforms? A: Wavelet transforms store large fractions of the strongest of the wavelet coefficients. B: The DWT decomposes each segment of time series via the successive use of low-pass and high-pass filtering at appropriate levels. C: Wavelet transforms can be used for reducing data and smoothing data. D: Wavelet transforms means applying to pairs of data, resulting in two set of data of the same length.

关于傅里叶变换正确的是： A: 傅里叶变换可以反映信号在局部范围中的特征。 B: 傅里叶分析比较适于平稳信号。 C: 短时傅里叶变换的基本思想是：把信号划分成许多小的时间间隔，用傅里叶变换分析每个时间间隔，以便确定该时间间隔存在的频率。 D: 使用有限宽度基函数进行变换不仅在频率上而且在位置上是变化的，它们是有限宽度的波，被称为小波(Wavelet)，基于它们的变换被称为小波变换。