Hardware and software considerations for active noise control

Active noise control is a real-time application of adaptive digital filtering which requires the full capabilities of a modern digital signal processing module. Even though frequencies are low, so that sample rates of a few kilohertz can be used, the extensive computations involved require efficient, high-speed processing. System hardware was designed to allow software-controlled versatility as well as fully automatic operation of a complete active noise control system. The ability to self-calibrate and self-model are important system features. Adaptive filter lengths determine the algorithm speed and necessary memory requirements. System limitations were primarily caused by on-chip memory size. The use of the Texas Instruments TMS32010 for this application and the improvements possible with the TMS32020 are described