An active apparatus includes a pressure sensor array. The pressure sensor array includes at least one transducer and a standard optical fiber mechanically coupled thereto. The active apparatus includes a distributed Bragg reflector fiber laser located within the optical fiber. The fiber laser emits a wavelength. The fiber laser consists of two fiber Bragg gratings, which define a linear cavity. The linear cavity is mechanically coupled to the at least one transducer. A pressure change detected by the at least one transducer causes at least one property change in the optical fiber. For example, the at least one property change in the optical fiber causes a change in the cavity length. The change in the cavity length causes a wavelength shift relative to the wavelength emitted by the fiber laser.

An active apparatus includes a pressure sensor array. The pressure sensor array includes at least one transducer and a standard optical fiber mechanically coupled thereto. The active apparatus includes a distributed Bragg reflector fiber laser located within the optical fiber. The fiber laser emits a wavelength. The fiber laser consists of two fiber Bragg gratings, which define a linear cavity. The linear cavity is mechanically coupled to the at least one transducer. A pressure change detected by the at least one transducer causes at least one property change in the optical fiber. For example, the at least one property change in the optical fiber causes a change in the cavity length. The change in the cavity length causes a wavelength shift relative to the wavelength emitted by the fiber laser.

An at least one acoustic sensor in form of a microphone configured for coupling with a tire pressure monitoring system and tire pressure monitoring system unit sensor to generally detect an acoustic signal within a tire interior space generated by a tire as the tire travels across a road surface. The detected signal can be used by various vehicle systems to generally determine a tire condition, such as, but not limited to, tread wear, tread depth, tire health, road condition, road characterization, status of noise reducing foam, and active noise cancelling.

A sensor assembly that includes a surface acoustic wave (SAW) sensor. The SAW sensor is adapted to measure a first environmental condition in response to receiving an RF signal. The SAW sensor includes a substrate having a layer of piezoelectric material. The SAW sensor further includes a interdigitated transducer (IDT) formed on the piezoelectric material. The IDT includes two comb-shaped electrodes having interlocking conducting digits in a first arrangement. The interlocking conducting digits in the first arrangement generates a first signal modulation of an RF signal received by the first IDT. The first signal modulation identifies the first SAW sensor.

A sensor assembly that includes a surface acoustic wave (SAW) sensor. The SAW sensor is adapted to measure a first environmental condition in response to receiving an RF signal. The SAW sensor includes a substrate having a layer of piezoelectric material. The SAW sensor further includes a interdigitated transducer (IDT) formed on the piezoelectric material. The IDT includes two comb-shaped electrodes having interlocking conducting digits in a first arrangement. The interlocking conducting digits in the first arrangement generates a first signal modulation of an RF signal received by the first IDT. The first signal modulation identifies the first SAW sensor.

The invention provides a signal processor that receives a signal containing information about an acoustic signal that is generated by at least one acoustic transmitter, that travels through an aerated fluid in a container, and that is received by at least one acoustic receiver arranged in relation to the container, including inside the container; and determines the gas volume fraction of the aerated fluid based at least partly on the speed of sound measurement of the acoustic signal that travels through the aerated fluid in the container. The signal processor also sends an output signal containing information about the gas volume fraction of the aerated fluid. The signal processor may be configured together with at least one acoustic transmitter, the at least one acoustic receiver, or both.

The invention provides a signal processor that receives a signal containing information about an acoustic signal that is generated by at least one acoustic transmitter, that travels through an aerated fluid in a container, and that is received by at least one acoustic receiver arranged in relation to the container, including inside the container; and determines the gas volume fraction of the aerated fluid based at least partly on the speed of sound measurement of the acoustic signal that travels through the aerated fluid in the container. The signal processor also sends an output signal containing information about the gas volume fraction of the aerated fluid. The signal processor may be configured together with at least one acoustic transmitter, the at least one acoustic receiver, or both.

The invention provides a signal processor that receives a signal containing information about an acoustic signal that is generated by at least one acoustic transmitter, that travels through an aerated fluid in a container, and that is received by at least one acoustic receiver arranged in relation to the container, including inside the container; and determines the gas volume fraction of the aerated fluid based at least partly on the speed of sound measurement of the acoustic signal that travels through the aerated fluid in the container. The signal processor also sends an output signal containing information about the gas volume fraction of the aerated fluid. The signal processor may be configured together with at least one acoustic transmitter, the at least one acoustic receiver, or both.

The invention provides a signal processor that receives a signal containing information about an acoustic signal that is generated by at least one acoustic transmitter, that travels through an aerated fluid in a container, and that is received by at least one acoustic receiver arranged in relation to the container, including inside the container; and determines the gas volume fraction of the aerated fluid based at least partly on the speed of sound measurement of the acoustic signal that travels through the aerated fluid in the container. The signal processor also sends an output signal containing information about the gas volume fraction of the aerated fluid. The signal processor may be configured together with at least one acoustic transmitter, the at least one acoustic receiver, or both.

A pressure sensor apparatus is disclosed. The pressure sensor apparatus includes a bulk acoustic wave (BAW) die having a die interface side and a pressure contact side, a sensor BAW resonator and a reference BAW resonator disposed on the die interface side of the BAW die, a control circuit die coupled to the die interface side of the BAW die via an attachment layer, and an extended opening on the pressure contact side that extends into a depth of the BAW die and is generally aligned with the sensor BAW resonator, the extended opening being configured to translate an external pressure on the pressure contact side onto the sensor BAW resonator.