Paraunitary systems are essentially multi-input, multi-output (MIMO) allpass filters. Let denote the matrix transfer function of a paraunitary system. Some of its properties include the following :
- In the square case (), the matrix determinant,
, is an allpass filter.
- Therefore, if a square
contains FIR elements, its
determinant is a simple delay:
Properties of Paraunitary Filter Banks
MIMO Paraunitary Condition