Orthonormal expansion of stable rational transfer functions
Xiaoning Nie, Daka Raghuramireddy, Rolf Unbehauen · Electronics Letters · 1991
It is shown that the transfer function of any stable recursive digital filter can be developed as an orthogonal (orthonormal) expansion with N functions where N is the order of the transfer function. This fact is particularly useful for structurally passive realisations of arbitrary recursive digital filters.