Patent ID: 7496135

Claim:
A DSL system comprising: mask selection criteria, the criteria comprising: a weighted ratio of upstream rates and downstream rates; and a cost function based in part upon the weighted ratio, wherein the cost function is defined according to the relation: cost ⁢ ⁢ function = ( 2 ⁢ x ⁢ ( dsrate ⁡ ( 2 ) - dsrate ⁡ ( 1 ) ) dsrate ⁡ ( 1 ) ) + ( ( usrate ⁡ ( 2 ) - usrate ⁡ ( 1 ) ) usrate ⁡ ( 1 ) ) , wherein dsrate(1) is the downstream rate of a first mask, dsrate(2) is the downstream rate of a second mask, usrate(1) is the upstream rate of the first mask, and usrate(2) is the upstream rate of the second mask; and a mask-selectable operator configured to select a spectral mask based on the mask selection criteria, wherein the mask-selectable operator selects a spectral mask based in part upon a determination of whether the cost function is greater than a predetermined value.