Caesium beam frequency standard, external oscillator generates a microwave frequency and induce those atoms to go into resonance, oscillating at that frequency for equal flux of atoms in the two hyperfine states.

铯束频率标准，外部振荡器产生微波频率并诱导这些原子进入共振，在该频率下振荡，从而获得两个超精细态中原子的相等通量。