Period characteristics of radiated noise at high frequency is investigated by a method based on short time Fast Fourier Transformation, and propeller speed is estimated.
用短时傅立叶分析的方法研究了辐射噪声在高频段时频变化的周期性，估计了目标的螺旋桨转速。
Conclusions MEC has the following advantages: less trauma, short operation time, fast postoperative recovery and lower expense.
结论小切口胆囊切除术具有创伤小，出血少、手术时间短、术后肠功能恢复快、住院医疗费用低等优点。
The results indicated that in comparison with the traditional control method, this method is of short starting time, fast responding speed and better dynamic and static performances.
结果表明，与传统的控制方法相比，该控制方法起动时间短、响应速度快，具有更好的动、静态性能。
The results indicated that in comparison with the traditional control method, this method is of short starting time, fast responding speed and better dynamic and static performances.
结果表明，与传统的控制方法相比，该控制方法起动时间短、响应速度快，具有更好的动、静态性能。
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