频率混叠在气体炮内弹道速度测量中的应用

Frequency Aliasing Used in Interior Ballistic Velocity Measurements for Gas Guns

从采样理论出发,分析频率混叠现象的产生规律及其在时域和频域中的表现形式,获得采样信号频率与原始信号频率的关系,论证了利用频率混叠规律恢复原始信号频率的可行性。采用数值方法模拟理想条件下的频率混叠信号,分析原始信号频率恢复方法。利用激光位移干涉仪和光束遮断法,开展了二级轻气炮内弹道速度的对比测量实验,根据频率混叠规律恢复干涉信号频率,得到的结果与光束遮断法测量结果一致,解决了内弹道长历程、高速测量中记录长度与采样率之间的矛盾。

The occurrence of frequency ali analyzed with sampling theory. Relations culated and shows that the frequency of quency aliasing ring method is gas gun frequenc obtained length or ball IS mea asln hip g and its representation between the sampled signal and original signal can be recovered ~ Ideal sampled signals with frequency aliasing are confirmed by numerical simulations. The interior sured by a laser displacement interferometer and y of the laser interference signal recovered by aliasing an from d the the sam optical beam break method, which solves the pling frequency in high velocity measurements istic velocity measurement. simulat ballistic and frequency domain are the original signal is cal- by using the rule of fre- ed,and the frequency recove velocity in a two-stage the optical beam break method. The rules is the same as the frequency contradiction between the recording of long time duration,such as interi-