11.1 Surround sound: chamberlin filters

Introduction

Chamberlin filter topology is frequently used in music applications where very narrow-band, low-pass filters arenecessary. Chamberlin implementations do not suffer from some stability problems that arise in direct-form implementationsof very narrow-band responses. For more information about IIR/FIR filter design for DSPs, refer to the Motorola Application Note .

Filter topology

A Chamberlin filter is a simple two-pole IIR filter with the transfer function given in [link] :

[link] and [link] show how the response of the filter varies with $Q_c$ and $F_c$ .

Exercise

First, create a MATLAB script that takes two parameters, $Q_c$ and $F_c$ , and plots the frequency response of a filter with a transfer function given in [link] . Then implement a Chamberlin filter on the DSP and compare itsperformance with that of your MATLAB simulation for the same values of $Q_c$ and $F_c$ . What do you observe?