A new factorization and structure for cosine modulated filter banks with variable system delay

A new design method for biorthogonal modulated filter banks is presented. It is based on a cascade of simple matrices, and it has some properties that have not been reported before. It represents filter banks with arbitrary overall system delay and filter length, it is shown that almost all cosine modulated filter banks can be described by this structure, and that it leads to a more efficient implementation than previous structures. Imposing certain symmetries on the matrices can be used to design low delay filter banks with identical (except for the sign) baseband impulse responses for the analysis and synthesis filter bank.