Filter Designs for VDSL Analog Front End

In the paper different fourth order filter designs with different transfer function approximations are discussed. Specifications on the filters are given for VDSL signal processing. Transfer functions and filter elements are given and sensitivity and noise for each design are calculated. The lowest sensitivity is obtained using a cascade of Rauch biquads, the lowest noise gives Akerberg-Mosberg design and the best selectivity is obtained using an elliptic filter. That leads to compromise in VDSL filter design. Also, transfer function approximation significantly determine overall specifications