Choice of central beat frequency is studied.

确定了中心拍频的最佳选择；

The envelope of the beat frequency is depicted as the grey areas.

信封的摆动频率是描述的灰色地带。

The envelope of the beat frequency will always be stationary in space; no angular velocity.

信封的摆动频率将永远固定在空间；没有角速度。

The experimental results were satisfactory, the beat frequency stability was 1.27×10 - 7 ( Allen variance ).

实验频率锁定结果良好, 频率稳定度为127×10-7 ( 阿仑方差 ).