关键词: 速率测量, 时频分析, 短时Fourier变换, 数据采集

Abstract: It is too difficult to capture all flying shrapnel and measure its speed，because the number of shrapnel is uncertain and the velocity of all shrapnel is various，when shell exploded.The paper has designed a target，which can capture all shrapnel coming from the exploded shell.According to the circuit of every area of the target，it gives a formula of the output signal.With a data acquisition equipment，it can acquire the signal data.Analyzing every signal segment with a short-time Fourier transform method，according to the amplitude-frequency characters of it，it can find the time point when shrapnel touched the target at the first time.Then it can calculate the shrapnel’s flying time from exploded position to the target.Measuring the distance from exploded position to the target，it can calculate the velocity of shrapnel.The paper gives a example，which can prove the design is feasible and correct.

Key words: speed measurement, time-frequency analysis, short-time Fourier transform, data acquisition