Design of Phase Control System for Parametric Array Loudspeakers Based on FPGA

Abstract

In order to achieve accurate control of the audible sound of the acoustic parametric array in the air, fine phase control of the ultrasonic signal as a carrier is required. By establishing the parametric matrix mathematical model and the directivity function formula, the effects of delay accuracy on the ultrasonic carrier and the audible sound deflection angle are simulated and analyzed. The control of 16-channel phase-controlled parametric array excitation signal is realized by using the fast parallel processing speed of FPGA. The signal processing circuit is designed to D/A conversion and amplification of the parametric array excitation signal to drive the piezoelectric transducer array efficiently. The experimental results show that the system can achieve fine control of the parameter array carrier transmission delay. The control accuracy of the parametric array carrier for the 40KHz carrier is 1 ns, and the error delay is less than 1 ns.