A Digitally Direct Driven Small Loud Speaker

摘要

Although a substantial quantity of music data is stored as digital information, as in the case of CDs and MDs, an analog drive is still the main component of a loudspeaker. If the speaker can be driven digitally, it becomes possible to perform all processes from the input to the output digitally. As a result, the analog power amplifier and some other components become unnecessary and a small, light, and high-quality speaker can be achieved. In this paper, we propose a basic idea of Digital Speaker and a digital-driven piezoelectric speaker employing multi-bit delta-sigma modulation. The prototype Digital Speaker implemented with a FPGA, CMOS drivers, and piezoelectric sub-speakers shows low THD performance.