Efficient technique of driving a directional loudspeaker

• Main Author: Lim, Fabian Zi Yao.
• Other Authors: Chong Yong Kim
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Power electronics; DRNTU::Engineering::Electrical and electronic engineering::Electronic systems::Signal processing
• Online Access: http://hdl.handle.net/10356/53920
• Institution: Nanyang Technological University

In modern society, continuous advancements in industries such as the media and the military have led to a push for greater technology in sound reproduction. There are directional loudspeakers that offer impressive audio directionality [1]. Such loudspeakers can improve the the immersive multimedia experience for the consumer or provide a means for specialized directional communications. A type of directional loudspeaker – the parametric loudspeaker, is one of such that can achieve high degree of audio directionality by its specialized use of ultrasonic emitters. While the parametric loudspeaker is a proven concept, it is known to have low electric-to-acoustic radiant power conversion efficiency due to the impedance mismatch between the circuit and the piezoelectric ultrasonic emitters [1]. One way to improve the conversion efficiency is to use a Class D amplifier in the integrated parametric loudspeaker system. Thus this project explores an efficient means to drive a parametric loudspeaker by means of a Class D amplifier based on the Nicera design schematic. This project will also explore a digital alternative to PWM signal generation by programming the Blackfin ADSP-BF533 Evaluation Board, to drive the Class D amplifier MOSFETs. This will replace the PWM signal generator component based on the popular 555 timer chip in the original Nicera Class D amplifier design setup.