Patent ID: 7739320

Claim:
A waveform equalizer comprising: a filter unit operable to perform waveform equalization on an input signal x(n) to generate an output signal y(n) to an nth iteration; an error estimation unit operable to estimate a waveform equalization error e(n) in the output signal y(n), and output the waveform equalization error e(n); an update amount calculation unit operable to calculate a coefficient update amount ΔC i (n) for an ith tap in the filter unit according to an equation ΔC i ⁡ ( n ) = α i ⁡ ( n ) × μ × e ⁡ ( n ) × x . * ⁡ ( n - i ) where μ is a constant, x*(n−i) is a complex conjugate of an input signal x(n−i), and α i (n) is a function of C i (n−1); and a tap coefficient storage unit operable to calculate a new tap coefficient Ci(n) of the ith tap using a tap coefficient C i (n−1) of the ith tap and the coefficient update amount ΔC i (n), and store the new tap coefficient C i (n) therein, wherein α i (n) monotonically increases with a magnitude of C i (n−1) in a range of 0<α i (n)≦1; and wherein the magnitude of C i ⁡ ( n - 1 ) ⁢ ⁢ is ⁢ ⁢  C i ⁡ ( n - 1 )  , ⁢ and α i ⁡ ( n ) = a ⁢ ⁢ if ⁢ ⁢  C i ⁡ ( n - 1 )  < b , α i ⁡ ( n ) = 1 ⁢ ⁢ if ⁢ ⁢  C i ⁡ ( n - 1 )  ≥ b , where a<1.