Abstract: An inventive accelerometer includes a proof mass and a pair of vibrating sensors. An excitation-and-detection circuit drives one sensor at resonant frequencies f1 and F1, with f1?F1; a second excitation-and-detection circuit drives the other sensor at resonant frequencies f2 and F2, with f2?F2. The vibrational modes driven at the frequencies f1 and f2 are the same for each sensor; the vibrational modes driven at the frequencies F1 and F2 are the same for each sensor. Compressive or tensile loads oppositely applied by the proof mass to the vibrating sensors cause a difference frequency ?F=F1?F2 to vary monotonically with acceleration of the apparatus along a sensing axis, from which a measurement of acceleration can be generated.

Abstract: An inventive accelerometer includes a proof mass, vibrating sensors, and an excitation-and-detection circuit. The vibrating sensors are substantially identical, and each exhibits corresponding fundamental and higher-order vibrational modes characterized by corresponding fundamental and higher-order resonant mode frequencies. The excitation-and-detection circuit drives each corresponding vibrating sensor at one of its resonant mode frequencies f1 or f2; the vibrational modes driven at the frequencies f1 and f2 are the same for each sensor. Compressive or tensile loads oppositely applied by the proof mass to the vibrating sensors cause a difference frequency ?f=f1?f2 to vary monotonically with acceleration of the apparatus along the sensing axis. The excitation-and-detection circuit includes at least one low-pass filter with a low-pass cut-off frequency fLP that is less than ?f.

Abstract: An inventive accelerometer includes a proof mass and a pair of vibrating sensors. Excitation-and-detection circuits drive vibrational modes of one sensor at resonant frequencies f1, F1, and F?1, and drive those same vibrational modes of the other sensor at resonant frequencies f2, F2, and F?2. Compressive or tensile loads oppositely applied by the proof mass to the vibrating sensors cause difference frequencies ?f=f1?f2, ?F=F1?F2, and ?F?=F?1?F?2 to vary monotonically with acceleration of the apparatus along a sensing axis. A measurement of acceleration can be generated based at least in part on a linear or nonlinear function of one or more or all of f1, f2, F1, F2, F?1, or F?2, and can be generated using a trained neural network.

Abstract: An inventive accelerometer includes a proof mass, vibrating sensors, and an excitation-and-detection circuit. The vibrating sensors are substantially identical, and each exhibits corresponding fundamental and higher-order vibrational modes characterized by corresponding fundamental and higher-order resonant mode frequencies. The excitation-and-detection circuit drives each corresponding vibrating sensor at one of its resonant mode frequencies f1 or f2; the vibrational modes driven at the frequencies f1 and f2 are the same for each sensor. Compressive or tensile loads oppositely applied by the proof mass to the vibrating sensors cause a difference frequency ?f=f1?f2 to vary monotonically with acceleration of the apparatus along the sensing axis. The excitation-and-detection circuit includes at least one low-pass filter with a low-pass cut-off frequency fLP that is less than ?f.

Abstract: An inventive accelerometer includes a proof mass and a pair of vibrating sensors. Excitation-and-detection circuits drive vibrational modes of one sensor at resonant frequencies f1, F1, and F?1, and drive those same vibrational modes of the other sensor at resonant frequencies f2, F2, and F?2. Compressive or tensile loads oppositely applied by the proof mass to the vibrating sensors cause difference frequencies ?f=f1?f2, ?F=F1?F2, and ?F?=F?1?F?2 to vary monotonically with acceleration of the apparatus along a sensing axis. A measurement of acceleration can be generated based at least in part on a linear or nonlinear function of one or more or all of f1, f2, F1, F2, F?1, or F?2, and can be generated using a trained neural network.

Abstract: An inventive accelerometer includes a proof mass and a pair of vibrating sensors. An excitation-and-detection circuit drives one sensor at resonant frequencies f1 and F1, with f1?F1; a second excitation-and-detection circuit drives the other sensor at resonant frequencies f2 and F2, with f2?F2. The vibrational modes driven at the frequencies f1 and f2 are the same for each sensor; the vibrational modes driven at the frequencies F1 and F2 are the same for each sensor. Compressive or tensile loads oppositely applied by the proof mass to the vibrating sensors cause a difference frequency ?F=F1?F2 to vary monotonically with acceleration of the apparatus along a sensing axis, from which a measurement of acceleration can be generated.

Abstract: A sensor for detecting mechanical perturbations represented by a change in an electrical signal includes a structure such as a cantilever, membrane, etc. and a field effect transistor such as a MOSFET embedded in the structure. The drain current of the embedded transistor changes with mechanical perturbations in the structure caused, for example, by a biochemical interaction being sensed. A scanning probe microscope utilizes the embedded MOSFET with a BiMOS actuator.