h sub s output______________________________________ 1 gt 0 gt 0 0 0 h k 1 h sub without 2 lt 0 gt 0 1 0 h k 1 h sub without 1 3 gt 0 lt 0 0 1 h k 1 h sub without 1 4 lt 0 lt 0 1 1 h k 1 h sub without______________________________________ first when updating term d k is negative i e d s 1 and tap coefficient h k is positive i e h s 0 as shown in row 2 of the above table negative leak is introduced in the positive tap coefficient cleverly this obtains because a one 39 s complement form of d k is on cable 460 and the carry in signal h s 0 as mentioned the one 39 s complement form of a negative number is one less than its two 39 s complement form hence a unit of negative leak is introduced second when updating term d k is positive i e d s 0 and tap coefficient h k is negative i e h s 1 as shown in row 3 positive leak is introduced in the negative tap coefficient this obtains in a deceptively simple manner since sign bit h s of tap coefficient h.