Patent ID: 7688711
Filing Date: 2010-03-30
Classification: G06F,G10L

Abstract:
1. Method, comprising: receiving by an audio signal processor a digital audio signal in the time domain; and transforming by the audio signal processor the digital audio signal from the time domain into a different domain, comprising: forming partitions of transform length N from said digital audio signal, which partitions overlap by N/2, wherein N is an integer multiple of ‘4’, performing a multiplication of a transform matrix Mh, said transform matrix having a size of N/2 rows and N columns, with each one of said partitions such that succeeding transformed signal partitions are provided, wherein said transform matrix is constructed in the form: wherein ‘a’ and ‘b’ are sub-matrices each having N/2 rows and N/4 columns and including ‘+1’ and ‘−1’ values only, and wherein lr( ) means that columns or elements of a sub-matrix are reversed in order, and wherein ‘a’ and ‘b’ are chosen such that a matrix has the rank N, whereby said transform matrix multiplication outputs N/2 output values per N input values representing a subsampling by a factor of ‘2’, thereby forming a transformed digital audio signal.