Patent Document ID: 8880572
Application ID: 13201572
Patent Status: 1

Claim One:
1. A method for determining N coefficients of an asymmetric prototype filter p 0 for usage for building an M-channel, low delay decimated analysis/synthesis filter bank comprising M analysis filters h k and M synthesis filters f k , k=0,. .. , M−1, wherein M is greater than 1, and having a transfer function, the method comprising the steps of choosing a target transfer function of the filter bank comprising a target delay D; wherein D is smaller or equal to N; determining a composite objective function e tot comprising a pass band error term e t and an aliasing error term e a ; wherein the pass band error term e t is associated with the deviation between the transfer function of the filter bank and the target transfer function; and wherein the aliasing error term e a is associated with errors incurred due to a decimation operation in the filter bank; wherein the pass band error term e t is determined by accumulating a squared deviation between the transfer function of the filter bank and the target transfer function for a plurality of frequencies; wherein the step of determining the composite objective function e tot comprises generating the analysis filters h k and the synthesis filters f k of the analysis/synthesis filter bank based on N given coefficients of the prototype filter p 0 ; wherein the M analysis filters h k and the M synthesis filters f k are modulated versions of the prototype filter; and determining N updated coefficients of the asymmetric prototype filter p 0 that reduce the composite objective function e tot .