$$\mathrm{W.}\mathrm{D.}\mathrm{W.}\text{[n] =}\{\begin{array}{cc}\sqrt{\frac{{\displaystyle {\sigma .}_{\mathrm{一世}=1}^N\mathrm{W.}[\mathrm{一世}]}}{{\displaystyle {\sigma .}_{\mathrm{一世}=1}^{\raisebox{1ex}{$N$}\!\left/ \!\raisebox{-1ex}{$2$}\right.+1}\mathrm{W.}[\mathrm{一世}]}}}& \text{如果}1\le .N<（\raisebox{1ex}{$N$}\!\left/ \!\raisebox{-1ex}{$2$}\right.）\\ \sqrt{\frac{{\displaystyle {\sigma .}_{\mathrm{一世}=1}^{N-N}\mathrm{W.}[\mathrm{一世}]}}{{\displaystyle {\sigma .}_{\mathrm{一世}=1}^{\raisebox{1ex}{$N$}\!\left/ \!\raisebox{-1ex}{$2$}\right.+1}\mathrm{W.}[\mathrm{一世}]}}}& \text{如果}（\raisebox{1ex}{$N$}\!\left/ \!\raisebox{-1ex}{$2$}\right.+1）\le .N<N\end{array}$$