Translations:The shaping filter/21/es

\left( {z_k - \sum\limits_n {f_n x_{k - n} } } \right)} \\

 \;\;\;\;\;\;\;   = \sum\limits_k 2 \left( {z_k  - \sum\limits_n {f_n x_{k - n} } } \right)( - x_{k - m} ) =  - 2\sum\limits_k {z_k x_{k - m} x_{k - m} } . \\ 

\end{align}</math>|7}}