Multi-channel active noise cancellation using the DSP56001 (digital signal processor)

The authors report on the performance of a portable active noise cancellation (ANC) system based around a PC hosted 20-MHz Motorola DSP56001 processor with a four-channel analog input/output (I/O) board connected to the real world via standard consumer audio components. The system will perform active noise cancellation over the frequency range of 65-500 Hz. Quantitative results are presented for the cancellation of single tone noise and of narrowband noise, and a measure of the ANC power spectrum is calculated for various parameters of the filtered-X LMS algorithm in different acoustic environments. Qualitative results based on human hearing perception of the attenuation of various narrowband and real world noise sources are also discussed