DETECTOR AND METHODS OF DETECTING

摘要

An ultrasonic detector (10) suitable for mounting in a position for surveying an area for a source of airborne ultra-sound, which detector comprises a sensor (20) for detecting an ultrasonic sound signal, characterised by a transducer (64) config-ured to produce a broadband ultrasonic sound signal for reception by said sensor (20) enabling said ultrasonic detector to perform a self-test.