Influence of magnetic field on quartz crystal oscillators

Recent investigations on the magnetic sensitivity of certain on-board quartz crystal oscillators are presented. A part of the study deals with the global magnetic sensitivity of the devices as a function of the magnetic field intensity and direction. Measurements were done on various ovened oscillators used in actual satellites. In addition, in order to determine the origin of the magnetically induced frequency shift, some components were separated from the oscillator and individually submitted to the magnetic field. The work presents the experimental setup, measurement procedures and results obtained at the CNRS laboratory in Besancon. Special attention is paid to the quartz crystal resonator itself. It is shown to have a sensitivity on the order of 10^-12/G. An explanation of the resonator´s magnetic sensitivity is given, and related verification experiments are presented