Filtros digitais em áudio

Abstract

The following work presents the performed procedures to the project and implementation of digital filters in one microcontroller device with the objective of filtering an audio signal. The main concepts about sound waves and the main problems encountered in communication systems due to undesirable signals are discussed. In addition, the paper approaches the concept of the application of filtering in the musical area through the equalization of sound. Also presenting the concepts of digital signal processing and the process of digital filtering of signals that sustain the work. Based on the concepts, the FIR and IIR digital filters were designed for simulations in Matlab and implemented in the STM32F407VG microcontroller. The simulations presented the filtering responses of two different input signals, an audio signal and a multisenoidal signal, for each of the projected filters, allowing to verify the performance and selectivity of each typology. In addition, with the results of the simulations it was possible to make comparisons, as to the order used and the selectivity obtained, of the FIR and IIR filters. Although only the practical results of the implementation of the FIR filters were obtained, it was possible to show that the responses of these filters are consistent with the simulations.