Investigation of directional audio system based on ultrasonic modulation

In this paper the structure and basic principle of directional audio system and its realization process are analyzed. An audio signal processing module with digital signal processor as its core is designed. According to the theory of nonlinear self-demodulation, three kinds of signal processing methods including DSB, distortion compensation DSB and SSB are introduced. Finally the directivity of ultrasonic transducer array is analyzed and simulated, the result presents that directivity of the sound can be effectively improved by using array technique.