Discrete-Time Peak and Shelf Filter Design for Analog Modeling

Jonathan Abel and David P. Berners $<${abel,dpberner} at uaudio.com$>$ (Universal Audio, Inc.)

A method for the design of discrete-time second-order peak and shelf filters is developed which allows the response of analog peak and shelf filters to be approximated in the digital domain. For filters whose features approach the Nyquist limit, the proposed method provides a closer approximation to the analog response than direct application of the bilinear transform. A peak filter and three types of resonant shelf filter are discussed, and design examples are presented.