Patent ID: 11747512

Abstract:
A method and apparatus for for sensing a change in an acceleration gradient δa(t) between two gravity fields a1(t) and a2(t) respectively sensed by the first and second proof masses, the first and second proof masses either being coupled only to a first resonator or being individually coupled to first and second resonators, the first resonator generating, in use, a signal at a frequency fD which is applied said second resonator, the second resonator being driven, in use, into a non-linear state corresponding to a modal resonant frequency fΘ wherein it generates a comb of frequencies each tooth of which is separated from each other by a frequency Δ which is frequency-wise proportional a frequency difference between fD and fΘ and also proportional to the change in said acceleration gradient δa(t), circuitry for selecting an nth tooth in said comb of frequencies where the frequency of the nth tooth is equal to fD+nΔ, circuitry for detecting a change in the frequency of the nth tooth and for generating a signal that is proportional to n times the change in an acceleration gradient δa(t).