A Click Modulation audio player

Abstract

This paper presents a technical solution for a audio player based on Click Modulation, capable of generating a PWM output out of a pre generated audio file. This modulation allows a spurious-free baseband with very low PWM switching rates. The player is based on a Texas Instrument (TI) C2000 32-bit microcontroller, that provides high resolution PWM generation with low system clock and very competitive price. Off-line Click Modulation and typical PWM modulation solutions (NPWM and USPWM) are also reported. In addition, overview of two analytical approaches for PWM spectrum determination and its results are used to help the different process used to generate the tested signals. Also a numerical approach is used for PWM spectrum determination. The experimental results of the off-line modulations used validate the theoretical and the numerical models used.