A Highly Directional Speaker with Amplitude-Phase Control Using a Digitally Direct-Driven System

Abstract

The paper proposes a novel directive control method with amplitude-phase control for a beamforming speaker by using a digitally direct-driven system with an array loudspeaker. This system can achieve high directivity and control side-lobe attenuation with the amplitude-phase control. The output pulse width is controlled using pulse width modulation for changing the amplitude and phase by using several 1-bit D flip-flops because the sub-loudspeakers are driven by 1-bit digital signals without digital-to-analog controllers and amplifiers. A segmented noise shaping dynamic element matching method is used to reduce the noise generated by the mismatch of sub-loudspeakers, which degrades the signal-to-noise ratio.