Active noise control in the concept of IoT

Abstract

This paper introduces a “proof of concept” system for Active Noise Control (ANC) where the audio data from the reference microphones are travelling through the already existing Ethernet network. The system realizes the active noise control with the help of a multi channel DSP card. The noise control algorithm is the Filtered Error Least Mean Square (ELMS) - an LMS variant -, which has already proven its efficiency previously in different environments. The audio data from the reference microphone to the DSP card are digitalised with the help of an ADSP-BF537 Ez-Lite Kit, and transmitted over Ethernet to a counterpart ADSP-BF537 Ez-Lite Kit card, which converts it back to an analogue signal to be able to be fed into the multi channel DSP card. The article highlights the usage of Ethernet network for audio transmission, and shows the problems that are caused by the properties of such medium, as well as the potential that lies in it. The working of the system and its efficiency is illustrated by measurement results.