The Time Dependence of a Quasimonochromatic Signal in the Region of Destructive Two-Beam Interference

Resumo

We consider the time dependence of a total signal from two point acoustic sources emitting similar quasimonochromatic signals (two-beam interference of quasimonochromatic waves). It is shown that the time dependence of the envelope function of the total signal is close to the time dependence of the envelope function of the signal from one source with accuracy up to the delay time. The delay time varies within the limits from the usual (geometric) time in the light bands of the interference field (the constructive-interference region) to the zero one (within the framework of the considered approximations) in the dark bands (the destructive-interference region). At the intermediate points of the interference field, the delay time appears to be complex, i.e., the signal is not only shifted in time, but also distorted.