The Research Of AGC And Audio Loudness Control Algorithm

It is obvious that the voice is the most popular communication way in our daily life. So the quality of the audio signals is considerably important for all the products that contain audio signals.In general,factors such as the audio standards.transmission conditions,human errors could all lead to the fluctuation of the audio signals and the inconsistencies of the audio loudness. These factors may make the listener uncomfortable. So in order to mitigate these impacts,we could just limit the signal amplitude or use automatic gain control (AGC) method to improve the audio quality.In this paper,we will first study the sound loudness and introduce a feature value that can be used in our algorithm. Then we will introduce the traditional voice AGC algorithm and the normalized least mean square algorithm (NLMS). Based on those two algorithms, we will propose a new algorithm that can maintain the consistency of the audio loudness.By using the feature value of the audio loudness, the algorithm will adjust the audio signals dynamically. At the beginning, the algorithm will be implemented on the MATLAB platform.The results of theprogram will be studied and analyzed. Then after several tests, we could finally get the optimal parameters and the desired results. Then by using the ALSA audio driver in Linux, we will design a simple audio player that can control the loudness of the input audio files.