Design of Automatic Control Technology of Passive Hydrogen Maser

The passive hydrogen maser is one of the widely used atomic frequency standards with outstanding performance, which utilizes a hyper-fine transition between two ground state levels of hydrogen atoms as a frequency discriminator. In the past, the space passive hydrogen maser is developed, which outputs the standard signal for satellite navigation and positioning systems. Its structures are suitable for space-borne but not convenient for user operation. For the passive hydrogen maser for surface use, the automatic control technology is significant. With the FPGA technique to design the servo loop and the temperature control loop, the passive hydrogen maser performance is improved and the debugging becomes easy. The long-duration frequency stability performance is better than 5*10
⁻¹³
at one second and 4*10
⁻¹⁵
at one day, which reached the international advanced level. To facilitate the operation personnel monitoring, the working status data of the passive hydrogen maser is displayed and critical parameters can be set by the liquid crystal display touchscreen through the display and control system. In addition, real-time control between the computer and the passive hydrogen maser is realized through network interface communication. Thus, the data and parameters can be monitored and controlled through IPC.