Design of Active Noise Control Systems With the TMS320 Family

An active noise control (ANC) system based on adaptive filter theory was developed in the 1980s; however, only with the recent introduction of powerful but inexpensive digital signal processor (DSP) hardware, such as the TMS320 family, has the technology become practical. The specialized DSPs were designed for real-time numerical processing of digitized signals. These devices have enabled the low-cost implementation of powerful adaptive ANC algorithms and encouraged the widespread development of ANC systems. ANC that uses adaptive signal processing implemented on a low-cost, high-performance DSP is an emerging new technology. This application report presents general background information about ANC methods. Contrasts between passive and active noise control are described, and the circumstances under which ANC is preferable are shown. Different types of noise-control algorithms are discussed: feedforward broadband, feedforward narrowband, and feedback algorithms. The report details the design of a simple ANC system using a TMS320 DSP and the implementation of that design.