在进行Ramsey作用时,以±π/2的相位差来调制同一频率点处两个周期微波脉冲,可以获得中心频率幅值为零的Ramsey条纹。这种方法可以直接通过中心频率处原子对探测光的吸收值变化来产生反馈本地振荡器的误差信号。理论上,相比于同相位Ramsey条纹,这种方法可以使得条纹信号幅值增加一倍。实验上,在积分球冷原子钟系统上,获得的相位调制Ramsey线型与理论计算相同,而且Ramsey条纹振荡幅值达到同相位下的1.6倍。 Ramsey fringes with zero center frequency can be obtained by modulating the two periodic microwave pulses at the same frequency with a phase difference of ± π / 2 during Ramsey. This method can generate the error signal of the feedback local oscillator directly through the change of the absorption value of the probe light by the atom at the center frequency. In theory, this approach doubles the amplitude of the fringe signal compared to Ramsey fringes with the same phase. Experimentally, the phase-modulated Ramsey line obtained on the integrating sphere cold atomic clock system is the same as the theoretical calculation, and the Ramsey fringe oscillation amplitude reaches 1.6 times of the same phase.