实用型氢激射器频标锁相接收系统

为了使上海天文台两台氢激射器频率标准更好地适应甚长基线干涉(VLBI)实验的要求,我们充分利用国内外新器件,采用新技术方案,研制出一种实用型氢激射器锁相接收系统。该系统具有接收灵敏度高(≤-120dBm)、噪音系数烛(≤1.8dB)、体积小、自动搜索人锁以及可靠性高等特点。本文主要以系统设计为实例,讨论了氢激射器频标锁相接收系统的总体设计原则、锁相环路的设计考虑和环路对系统的噪声抑制的定量估算等问题。最后,介绍了运用该系统后氢激射器频标的短期频率稳定度达到1.88×10-~(13)/S、3.7×~(-14)/10S、9.2/10~(-15)/100S9.5×10~(-15)/1000s,完全满足了甚长基线干涉实验的需要。

The Practica1 Phase--1ocked Receiver System Using the Hydrogen Maser in VLBI

The hydrogen maser frequency standard is one of practi- cal type frequency standards which are of the best frequency stabili- ty, so it is widely applied in many fields of modern science, especially in VLBI radio astronomy. Since the frequency stability of the hydrogen maser is transmitted to VCXO by means of phase-locked receiver system, while VCXO is directly used by user, the phase-locked receiver system decides the best transmission of frequency stability of the hydrogen maser frequency standard. This paper first describes the desi gn of the new high stable phase-locked receiver system, then gives the result of frequency stability of two hydrogen maser frequency standards which are provided with the new phase-locked receiver system at VLBI Seshan Sec- tion of Shang hai Observation.