657 results about "Doppler effect" patented technology

A piezoelectric thin film sensor array is used to scan and capture biometric data, for example, a fingerprint image. In one embodiment, a multi-layer structure includes a PVDF layer in between two conductor grids arranged orthogonally to one another. Urethane can be added to one side where a finger is placed. A foam substrate can be used as a support. In one feature, the PVDF, and grids can be peeled off like a label for easy replacement. Multiplexers are switched to scan the sensor. A single pixel or a group of pixels can be detected and output to an image memory. The presence of a fingerprint ridge is detected by virtue of a ring-down oscillation that arises from reflection when an electric field is applied to the piezoelectric thin film sensor array at a pixel in contact with the fingerprint ridge. For example, such a ring-down value associated with a fingerprint ridge can be detected at about 150 ns. (or 5 cycles at 30 MHZ). Other reflections indicative of additional biometrics (e.g. from tissue, blood, bone, fingernail, etc.) can also be detected. A Doppler effect due to reflections from circulating blood can also be detected. Such a Doppler effect can provide further information about direction and speed of blood circulation. An instantaneous pyroelectric effect can also be detected to indicate a live finger presence.

An aircraft-mounted base transceiver station (mBTS) for providing intermittent coverage in a cellular radio network. The mBTS utilizes the existing protocol of its terrestrial counterparts, thereby avoiding dual-mode devices and enabling common usage of terminal monitoring and device management systems for devices connected to a single radio access network even when outside terrestrial coverage areas. The aircraft follows a transient flight pattern, providing intermittent flyover connectivity for remote radio device such as machine-type devices. Connectivity may be store and forward. Channel usage may be adjusted to avoid interfering with terrestrial communication cells during flyover. Doppler effects due to aircraft speed may be accounted for. The mBTS may be configured to service in-range radio devices which are outside a Doppler-inhibited region and / or to prioritize communication with devices based on expected time outside the Doppler-inhibited region. An aircraft mounted antenna may have a radiation pattern focused toward devices outside the Doppler-inhibited region.

A two-DOF (degree of freedom) heterodyne grating interferometer displacement measurement system comprises a two-frequency laser, a grating interferometer, a measuring grating, a receiver, and an electronic signal processing part. The grating interferometer comprises a polarizing beam splitter, a reference grating and a refraction element. The measurement system measures displacement according to optical grating diffraction, optical Doppler Effect and optical beat frequency principle. A two-frequency laser beam emitted by the two-frequency laser enter the grating interferometer and the measuring grating before two light signals are output to the receiver, and the signals are sent to the electronic signal processing part. When the grating interferometer is in two-DOF linear relative motion with the measuring grating, the system can output two linear displacements. The measurement system allows for sub-nano or higher resolution and precision, and can measure two linear displacements simultaneously. The measurement system has the advantages of insensitivity to environment, high measurement precision, small size, light weight and the like, and after the measurement system is used as a lithography machine ultra-precision workpiece bench position measurement system, comprehensive performances of a workpiece bench can be improved.