pinger

English Thesaurus

1. a pulse generator used for echo sounding in sonar (noun.artifact)

hypernym	:	pulse generator,
definition	:	a generator of single or multiple voltage pulses; usually adjustable for pulse rate (noun.artifact)

part meronym	:	asdic, echo sounder, sonar,
definition	:	a measuring instrument that sends out an acoustic pulse in water and measures distances in terms of the time for the echo of the pulse to return (noun.artifact)