他试图睡觉，但得到的是整夜的迫击炮和直升机声。
He tries to sleep but gets woken by mortars and helicopters all night long.
在对直升机声信号特征进行分析之后，提出了一种基于谐波恢复的ESPRIT方法来提取直升机声信号谐波频率作为特征用以识别直升机声目标。
Based on analysis of spectral characteristic of helicopter acoustic signal, a method of extracting harmonic frequencies from the helicopter acoustic signal via ESPRIT is proposed.
Sara对机上人员大声叫喊，以盖过直升机机翼的旋转声，“他失了很多血，低血容量性休克！”
Sara shouts over the sound of the whirling chopper blades, “He’s lost a lot of blood.
应用推荐