小波重构的时候waverec(c,l,'db1');其中c和l都应该是列向量，所以将数个向量合并成c时最好分别将他们弄成行向量，合并后转置就成了列向量。(When the wavelet reconstruction is waverec (C, l,'db1'), C and l should all be column vectors, so when several vectors are merged into C, it is best to make them a row vector respectively, and then merge into a column vector.)