An Integrated NAH/Beamforming Solution for Efficient Broad-Band Noise Source Location

Near-field Acoustical Holography (NAH) is a powerful, high-resolution noise source location technique for low-to-medium frequencies, requiring however often too many measurement positions at high frequencies. Beamforming provides too poor resolution at low frequencies, but very good resolution at high frequencies with relatively few measurement points. A combination of the two techniques therefore seems attractive. But where traditional NAH requires a regular array, Beamforming can provide the attractive high-frequency performance only by the use of irregular array geometries. The present paper describes a system that enables NAH and Beamforming to be supported with the same irregular array, and which can provide comparable scaling of the output from the two types of array measurement.