Microphone-Based Speech Signal Acquisition and Filtering for Noise Reduction

The objective of this course project is to acquire speech signals using a microphone and implement filtering techniques for noise reduction. The development is carried out on the MATLAB 7.1 platform. The design process encompasses three main stages: First, we capture speech signals through MATLAB's audio input functions (such as audiorecorder) and analyze their frequency spectrum using FFT algorithms to identify noise characteristics. Next, we design a Hamming window-based FIR filter by specifying cutoff frequencies and filter order, utilizing MATLAB's fir1 function with windowing techniques to achieve optimal frequency response. Finally, we apply the designed filter using convolution operations (filter function) to process the acquired signal. After filtering implementation, the processed speech signal demonstrates noticeably improved clarity compared to the original recording, with reduced background noise and enhanced vocal frequencies. This project successfully achieves its primary design goals through systematic digital signal processing methodology.