The roles of integration time and acoustic multipaths in determining the structure of CW line spectra

A recently developed normal mode theory of the acoustic field generated by a uniformly moving time harmonic point source [K. E. Hawker, "A Normal Mode Theory of Acoustic Doppler Effects in the Oceanic Waveguide," J. Acoust. Soc. Am., scheduled for publication in March 1979] is used to study the relative importance of multipath and integration time effects in determining the structure of cw line spectra. Widths are shown to result from an interplay between three effects, acoustic multi-path (Doppler) broadening, intrinsic width due to the finite integration time, and a "range rate" or FM slide effect due to the combination of finite integration time and a time variable instantaneous frequency.