Precision device for measuring the three dimensional spectra of complex intensity

On the basis of the algorithms documented in the companion paper 2aSPb1 of Acoustics'17 Boston POMA where the complex intensity is defined and its physical meaning has been described, the block diagram of a possible device for precision measurement of the 3D complex intensity is here proposed. Its outline is based on the spectral equation linking respectively the active and reactive intensity to the real and imaginary part of the wave impedance through a frequency dependent factor given by the autospectrum of the particle velocity (energy-mass equation). In order to estimate the measurement precision of this device, an advanced calibration process requiring three different active and reactive reference fields is included in the layout, and calibration errors obtained with different correction functions in different field conditions are reported.