The DPOAEs measured in the ear canal is the vector sum of two different components. The nonlinear and the linear components are characterized by very different group delay so that they can be effectively separated in the time-frequency domain. The two components are differently sensitive to the f2/f1 ratio. In particular, in the case of the nonlinear component, if the ratio approaches unity, due to the increase of the overlap between the f2 and f1 excitation patterns, the generation region becomes wider. The widening of the generation region causes a large negative interference phenomenon, due to the fact that the contribution to the fdp amplitude comes from wavelets with different phase. This behavior cannot be observed in the case of the linearly generated component, because the phase spread is compensated in the forward traveling wave path to the fdp place (beamforming effect). In this study, the result of analytical and numerical modeling are compared to experimental data, showing that the different models are able to reproduce different aspects of the DPOAE generation and transmission phenomenology.
Sisto, R., Botti, T., Moleti, A. (2015). DPOAE short and long latency components and the beamforming effect: Experiment and model. In Proceedings of the 22nd International Congress on Sound and Vibration. International Institute of Acoustics and Vibrations.
DPOAE short and long latency components and the beamforming effect: Experiment and model
MOLETI, ARTURO
2015-01-01
Abstract
The DPOAEs measured in the ear canal is the vector sum of two different components. The nonlinear and the linear components are characterized by very different group delay so that they can be effectively separated in the time-frequency domain. The two components are differently sensitive to the f2/f1 ratio. In particular, in the case of the nonlinear component, if the ratio approaches unity, due to the increase of the overlap between the f2 and f1 excitation patterns, the generation region becomes wider. The widening of the generation region causes a large negative interference phenomenon, due to the fact that the contribution to the fdp amplitude comes from wavelets with different phase. This behavior cannot be observed in the case of the linearly generated component, because the phase spread is compensated in the forward traveling wave path to the fdp place (beamforming effect). In this study, the result of analytical and numerical modeling are compared to experimental data, showing that the different models are able to reproduce different aspects of the DPOAE generation and transmission phenomenology.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.