最近，英国利兹大学的科研人员研制成功了一种新型警报器，它可以使人们准确地判断装有该种警报器的车辆位置。主要采用了多频率的声音信号，使警报声更有层次感和主体感，因而比传感单调的警报声更容易让人准确地判断其位置。救护车、警车和救火车等在紧急的情况下需要发出警 Recently, researchers at the University of Leeds in the United Kingdom have succeeded in developing a new type of siren that enables people to accurately determine the location of a vehicle equipped with such an alarm. The main use of multi-frequency sound signal, so that the alarm sound more sense of hierarchy and the main body, and thus more sensitive than the monotonous alarm sound more accurate to determine its location. Ambulances, police cars and firetrucks need to be alerted in case of emergency