Filters for VDSL technology

In this paper, different the third order filters designs with different transfer function approximations are discussed. The filters should fulfill the specifications for the VDSL signal processing. The standard transfer function approximations are chosen: the Butterworth, the Chebyshev, the symmetric impulse response and the elliptic. The filters are designed using the fully differential sections with the small number of elements to obtain the low noise and the high dynamic range, and the low sensitivity. The transfer functions and the filter elements are given and the sensitivity and the noise for each design are calculated. The best results are obtained for the third order filter where the second order block follow the first order block.