Patent ID: 7778314

Claim:
A far-end crosstalk (FEXT) detector, comprising: a first delay line adapted to receive a plurality of symbol decisions and to output delayed symbol decisions therefrom; a second delay line adapted to receive a plurality of slicer errors and to output delayed slicer errors therefrom; and single tap FEXT canceller training means coupled to said delay lines and operative to generate a single FEXT filter coefficient as a function of a previous FEXT filter coefficient update, said delayed symbol decisions and delayed decision error signal without disturbing a regular operation mode, wherein said training means is operative to generate said single FEXT filter coefficient in accordance with the following equations: if d (index of coefficients within said delay lines) is positive: e i,j,d f ( n )= e i ( n )− f i,j,d ( n )· c j ( n−d ) f i,j,d ( n+ 1)= f i,j,d ( n )+μ·e i,j,d f ( n )· c j ( n−d ) if d is negative: e i,j,d f ( n )= e i ( n−d )− f i,j,d ( n )· c j ( n ) f i,j,d ( n+ 1)= f i,j,d ( n )+μ e i,j,d f ( n )· c j ( n ) wherein e i (n) is the decision error at pair i, e i,j,d f (n) is the error at pair i after single tap FEXT cancellation of pair j, f i,j,d (n) is the single FEXT filter coefficient being trained, c j (n−d) is the received symbol decision at the adjacent j th pair with a delay of d symbols and μ is the step size.