频闪观测器（Stroboscope）又称同步定时仪，可测量反复运动所需的时间。

频闪观测器是一个可以转动的圆盘，圆盘上有狭缝，能发出脉冲光。频闪观测器大多用来量度水波、脑波的频率。

A strobe light or stroboscopic lamp, commonly called a strobe, is a device used to produce regular flashes of light. It is one of a number of devices that can be used as a stroboscope. The word originated from the Greek strobos, meaning "act of whirling."