Phase Comparison Method Suitable to Measure H-Maser Performance

摘要

Very Long Baseline Interferometry is one of the modern specialized applications where phase noise instability has to characterized not only for short term, but also over very long periods of time. This technique is utilized by radioastronomers to draw sky maps with angular resolutions of a few milliaroseconds and by geophysicists to measure continental plate motions, with precision of a few centimeters across earth diameter distances. These types of observations are performed by networks of radiotelescope antennas, each of which needs a H-Maser frequency standards to preserve, in the receiving down conversion mixing process, the phase of the signal coming from sky radio sources.