A theorem providing bounds on digital filter scaling factors
R.H. Brackert, H. J. Orchard, Alan N. Willson · IEEE Transactions on Signal Processing · 1991
A theorem which gives a lower bound on the magnitude of a rational function H(z) when evaluated on the unit circle in the complex plane is proved. In the special case of biquadratic H(z), the theorem yields valuable insights and bounds which are useful for digital filter scaling. Two examples with zeros on the unit circle are given.>