John C. Burgess
David I. Havelock
Inst. for Microstructural Sci., Natl. Res. Council, Ottawa, Ontario K1A 0S1, Canada
Atmospheric turbulence affects both the amplitude and phase (instantaneous frequency) of transmitted sound. The effect is similar to that of random variations in sound propagation velocity. Two methods to estimate the time-varying phase are discussed, one based on an FFT with optimum data windows and the other based on the discrete Hilbert transform. Accuracy of the two methods is compared using synthesized single-frequency test signals. Comparisons are made between the methods applied to acoustic data obtained from sound propagating through a turbulent atmosphere. [sup a)]On leave from the University of Hawaii.