It electronically translates these signals by heterodyning them down into the audible range so that a user can hear these sounds through a headset and see them as intensity increments on the meter. Heterodyning works the same as a radio in that it accurately transforms the sounds so that they are easily recognized and understood.
The advantage of Ultrasound technology is simple to understand. Ultrasound is a high frequency, short wave signal. When compared with the sounds we humans can hear, the size of the sound waves are extremely small. This property provides advantages:
Ultrasound is very directional
Ultrasound can be easily blocked or shielded
Ultrasound instruments can be used in noisy environments
Ultrasound changes provide early warning of potential problems