Patent ID: 7218672

Claim:
An apparatus for calculating a plurality of feedback filter tap coefficients in a feedback filter of a decision feedback equalizer, wherein said apparatus limits a magnitude of each of the plurality of feedback filter tap coefficients to a total energy of the feedback filter tap coefficients to reduce error propagation in said decision feedback equalizer, and wherein said apparatus calculates each of the plurality of feedback filter tap coefficients using: g n k + 1 = g n k + μ ⁢ ⁢ e k ⁢ a k - n - λ ⁢ ⁢ ∂ J ∂ g n where g n k is a feedback filter tap coefficient at time k, μ is an adaptation speed constant, e k is an error term, α k−n is a value of feedback filter tap data in said feedback filter at time k, J is a constraint cost function, and λ is a small positive constant.