The composition of pulses and their use in underwater sound measurements are examined from a nonclassical viewpoint. The multiple aspects of the complicated subject of pulse modulation are treated with particular consideration for the practitioner rather than the mathematician or the theoretical physicist. Exception is taken to the following generally held notions concerning pulsed measurements: (1) If the response of the device being measured is to approach the steady-state condition, the number of cycles in the driving pulse must equal the Q of the driven device at the operating frequency. (2) The buildup and decay times of the pulse are equal. (3) The frequency of the received signal is the same as that of the transmitted signal.