Study And Design For Parametric Loudspeaker System Based On DSP

The parametric loudspeaker is a kind of new products employing the prospect extensively, it can make the sound have directions. The domestic study on parametric loudspeaker system is still at the stage of exploring at present. On the basis of analyzing and studying foreign parametric loudspeaker products in the article, combine and use the extensive digital signal day by day to deal with the device at present -DSP chip, aim at exploring a new kind of systematic implementation methods of parametric loudspeaker, it is design of the parametric loudspeaker system and application of DSP chip that have put forward a kind of new design philosophy.Study and design to the parametric loudspeaker system include the contents of two respects: software and hardware. Study in the article focal point software part, directed primarily to study and design the digital signal processing algorithm in the parametric loudspeaker system. The main algorithm among them is as follows: dynamic range controllor, distortion- reduced preprocessing, sinusoidal wave oscillator and amplitude modulator. The dynamic range controller is a brand-new studying subject in the the digital audio signal processing too, it can utilize to spend dynamic range system fully, can play distortion of reducing, improve sound and raise voice function of sonority.It includes some following more concrete algorithms: noise gate, expanding device, compressing device, amplitude limiter, peak measurement , time constant generator , dynamic law and gate limit, logarithm and anti logarithm operations,etc. Distortion-reduced preprocing is one far-field principle that get distorted to predict the solution according to non-linear acoustics, utilize it input and output relational expression can come reduce distortion of sound that can hear before exporting; The sinusoidal wave generator is used for producing the ultrasonic signal carrier, realization algorithm have look-up table, recursive oscillator and Taylor series expansion approach,etc. Amplitude modulator is a committed step in the signal processing, it has determined to output working efficiency and quality of the launcher directly. Adoptable amplitude modulate scheme have double sideband amplitude modulator, single sideband amplitude modulator and quadrature amplitude modulator etc. The hardware part of the parametric loudspeaker system is mainly a design based on DSP experimental system interface circuit, including the designs of ultrasonic power amplification circuit, ultrasonic launcher,etc.Deal with the algorithm to compare and analyze to many kinds of digital signal processing in the article, and carry on emulation and design of the algorithm with the aid of MATLAB/SIMULINK, carry on software emulation to the algorithm in the integrated development environment CCS of DSP finally. Design and finish software emulation and realize of digital signal processing algorithm such as dynamic range...