The battlefield medic is a staple of war movies, but rarely depicted is one challenge that goes beyond dodging bullets: noise.
U.S. Army acoustical engineers have developed a new stethoscope that can outperform its electronic predecessors by detecting a human heartbeat in intensely noisy environments, such as inside a military helicopter, according to LiveScience. Unlike others before it, the new stethoscope has a special head that can generate ultrasound waves, or sound frequencies that can cancel out external noises as high as 120 decibels.
Background noise on ambulances, helicopters or within crowds typically render electronic and traditional stethoscopes useless. But for the new device to work, researchers must ensure it does not generate emissions through the ultrasound waves that affect aircraft or other equipment.