Nearfield acoustic holography based on wave superposition algorithm for cyclostationary sound filed

Abstract

The seriously modulated radiation sound waves, as a kind of special nonstationary signal in the engineering, can be considered as cyclostationary. The modulating feature can not be understood clearly via the reconstructed sound field by conventional nearfield acoustic holography (NAH). A cyclostationary NAH (CYNAH) technique based on wave superposition algorithm (WSA) is suggested for reconstructing the cyclostationary sound field, which can be applied to the cyclostationary acoustic sources with complicated profiles. The information of modulating wave can be understood by the reconstructed hologram of cyclic spectrum density (CSD), in which the distribution of modulating wave is visualized and the location of modulating wave can be determined. The simulation and the experiment verified that the modulating characteristic can be understood by CYNAH based on WSA. The main advantages of WSA, including the high calculation accuracy and calculation efficiency due to the exclusion of uniqueness and singularity problems inherent in the boundary element method, are retained in the presented CYNAH procedure.