Advanced Time-Domain Beamforming Techniques

Aeroacoustic beamforming for static sources like wind tunnel models is usually performed in the frequency-domain because special techniques that exploit the structure of the cross spectral matrix are formulated in the frequency-domain. This usually restricts the analysis to narrowband processing. Simple time-domain beamforming formulas that implement the diagonal deletion and cross-array beamforming techniques are presented. Examples using synthetic data show that the techniques are effective and that increasing the processing bandwidth can reduce the array sidelobes and improve the performance of diagonal deletion in removing the effects of microphone self noise.