Mutual-mode drive level dependence in dual-mode resonators

Dual-mode oscillators are widely used in high-stability frequency references. The presence of the second excited mode allows one to get information about the temperature of crystal resonator or its aging. However, dual-mode excitation results in the appearance of additional components of basic mode frequency instability. One of them is mutual drive level dependence, i.e. the first mode frequency versus the second mode excitation level. This phenomenon has not been practically investigated up to now. The given work deals with the detailed analysis of mutual drive level dependence for dual-mode resonators with wide-spread SC and DT cuts. This work presents the results of experimental investigation on the basis of which the causes and components of mutual drive level dependence are analyzed. The consequences of this dependence (namely worsening of oscillator frequency stability) are analyzed as well. The work is based on the experimental data and has practical orientation