possible implementation each activation of the filterbank may be implemented as a direction to a commutator to address and select one particular arm of a polyphase filter structure the arrows shown in fig2 are labeled with the phases of interest at each iteration at the beginning we have three phases labeled u201c 0 u201d between which the true maximum may lie at iteration 1 the control unit causes the computation of the output of the filterbank at phases labeled u201c 1 u201d the position of these phases is somewhere in the interval of interest and could be trivially chosen as a symmetric bisection of the regions defined by the peak and two adjacent samples other techniques of bisection based on the golden rule of the fibonacci sequence may be employed as well see knuth u201c the art of computer programming searching and sorting u201d at each iteration the locations of the peaks as computed to that point are used to decide the phases of interest for the next computation the rule used to determine the phases of interest is that these phases must lie on either side of the current maximum for iteration 3 the regions of interest are defined by the center point labeled u201c 0 u201d and the two points labeled u201c 2 u201d on either side of u201c 0 u201d since.