Paraconjugation

Paraconjugation is the generalization of the complex conjugate transpose operation from the unit circle to the entire $z$ plane. A paraunitary filter bank is therefore a generalization of an orthogonal filter bank. Recall that an orthogonal filter bank is one in which $\bold{E}(e^{j\omega})$ is an orthogonal (or unitary) matrix, to within a constant scale factor, and $\bold{R}(e^{j\omega})$ is its transpose (or Hermitian transpose).