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

The Active Noise Controller (ANC) system described here implements a practi cal design that significantly decreases background noise of signals common to most portable audio devices. This is achieved by a mixture of convention al ANC blocks with less traditional implementations, including a combined F IR/IIR structure using switched-capacitor blocks such as summers, integrato rs, multipliers, and delays. The proposed design also works as a stand-alon e system and it has been successfully implemented on a 12-mum CMOS technolo gy.