An Audio Quality Evaluation of Commercial Digital Radio Systems

In this paper, the subjective audio quality of various digital radio systems is evaluated. In order to estimate the true audio quality of a commercial digital radio service, test audio signals were acquired directly from the digital radio equipment in the field. Twenty-one subjects participated in the test after pre-screening. The evaluation process consisted of two phases. In the first phase, the audio quality of each system was evaluated as a function of the bit rates, and the relationship between the audio quality and the channel capacity of each system was obtained. In order to confirm the evaluation consistency, in the second phase, the audio quality as a function of the systems was evaluated. Assuming that the digital radio equipment tested in this paper is used for service, these evaluation results provide the true audio quality of commercial digital radio services for various types of systems and bit rates, and can be used as a reference to determine the optimal channel capacity of digital radio service for a given target audio quality.