| long-duration transmission of sound
Note 1 to entry: The duration of transmission is long compared to a specified duration of interest. In many cases, the relevant duration of interest is the maximum duration of flight from transmission to reception.
Note 2 to entry: The sound is constrained within a constant and relatively narrow band of frequency, such that continuous waves are often described as a single frequency. Often, the term "continuous wave" presumes a sinusoidal signal.
Note 3 to entry: Note that the use in underwater acoustics of the words "transmit", "transmitter" and "transmission" to describe the process of sound radiation by a source is commonplace, but this deviates from the usage prescribed in IEV 702-02-05 where the words "emit", "emitter" and "emission" are preferred.