A firmware system for phase measurements in extremely low and ultralow frequency ranges

Abstract

In experimental investigations of artificial and natural signals in extremely low frequency (ELF) and ultra low frequency (ULF) ranges, it is necessary to measure amplitudes and relative phases of the elec tromagnetic field components in a network of stations. The phase measurement includes accurate synchro nization of data with the universal time. In this work, the geophysical data acquisition system, which allows one to synchronize measurement results and the coordinated universal time with an accuracy of a few micro seconds, is described. Methods for processing the electromagnetic field components of the harmonic signal source, recorded by this data acquisition system, are proposed.