An environmental condition may be measured with a sensor (10) including a wire (20) having an ultrasonic signal transmission characteristic that varies in response to the environmental condition by sensing ultrasonic energy propagated through the wire using multiple types of propagation, and separating an effect of temperature on the wire from an effect of strain on the wire using the sensed ultrasonic energy propagated through the wire using the multiple types of propagation. A positive feedback loop may be used to excite the wire such that strain in the wire is based upon a sensed resonant frequency, while a square wave with a controlled duty cycle may be used to excite the wire at multiple excitation frequencies. A phase matched cone (200, 210) may be used to couple ultrasonic energy between a waveguide wire (202, 212) and a transducer (204, 214).

A MEMS inertial sensor device, method of operation, and fabrication process are described with a MEMS inertial sensor, drive actuation unit, drive measurement unit, and PLL circuit coupled together in operational engagement, where the MEMS inertial sensor includes a substrate, a proof mass positioned in spaced apart relationship above the substrate, a proof mass suspension member connected on a first end to the proof mass and connected on a second end to an anchor fixed to the substrate to enable the proof mass to laterally oscillate over the surface of the substrate, and a compliant stop structure positioned in relation to the proof mass suspension member to physically engage with lateral oscillating movement of the proof mass suspension member past a desired stroke travel distance without physically preventing lateral oscillating movement of the proof mass, thereby stiffening a spring stiffness measure of the proof mass suspension member.

A MEMS inertial sensor device, method of operation, and fabrication process are described with a MEMS inertial sensor, drive actuation unit, drive measurement unit, and PLL circuit coupled together in operational engagement, where the MEMS inertial sensor includes a substrate, a proof mass positioned in spaced apart relationship above the substrate, a proof mass suspension member connected on a first end to the proof mass and connected on a second end to an anchor fixed to the substrate to enable the proof mass to laterally oscillate over the surface of the substrate, and a compliant stop structure positioned in relation to the proof mass suspension member to physically engage with lateral oscillating movement of the proof mass suspension member past a desired stroke travel distance without physically preventing lateral oscillating movement of the proof mass, thereby stiffening a spring stiffness measure of the proof mass suspension member.