Overview of the phase and amplitude gradient estimator method for acoustic intensity

This paper summarizes the theory, benefits, and example applications of a recently developed method for frequency-domain acoustic intensity estimation from multimicrophone probes. The phase and amplitude gradient estimator (PAGE) method can use the same hardware as the traditional method, but greatly improves bias error estimates for complex intensity by obtaining the gradient of the amplitude and phase separately. The theory described includes the bias error improvements, including phase unwrapping beyond the spatial Nyquist frequency. Applications to jet noise, outdoor sound source localization, and to improved broadband sound power estimates are described.