Variable-block-size lapped transforms

A structure for implementing lapped transforms with time-varying block sizes that allows full orthogonality of the transient transforms is presented. The formulation is based on a factorization of the transfer matrix into orthogonal factors. Such an approach can be viewed as a sequence of stages with variable-block-size transforms separated by sample-shuffling (delay) stages. Details and design examples for a first-order system are presented.