Analog implementation of an active noise controller system for portable audio applications

The active noise controller (ANC) system described here implements a practical design that significantly decreases background noise of signals common to most portable audio devices. This is achieved by a mixture of conventional ANC blocks with less traditional implementations, including a combined FIR/IIR structure using switched-capacitor blocks such as summers, integrators, multipliers, and delays. The proposed design also works as a stand-alone system and it has been successfully implemented on a 1.2-/spl mu/m CMOS technology.