Radio science experiment of Voyager-2 spacecraft occultation by Neptune

NASA-JPL and Japan's Institute of Space and Astronautical Science collaborated at the Usuda Deep Space Center in the Voyager-2 Neptune occultation experiment. Phase information is extracted from the recorded data by means of a digital filter that can track the carrier frequency and narrow the filter bandwidth by up to 3 mHz. The results thus obtained can verify the phase-stability of the receiving system as a whole. Problems experienced by low-noise amplifiers were solved through the use of system redundancies.