spatial frequency

例句：

1. 1.The spatial frequency of the signal is critical for detecting its presence.
   信号的空间频率对于检测其存在至关重要。
2. 2. In electromagnetic theory, spatial frequency refers to the distribution of energy in space.
   在电磁理论中，空间频率指的是能量在空间的分布。
3. 3. Spatial frequency analysis is used to study the behavior of materials under stress.
   空间频率分析用于研究材料在应力下的行为。