In order to detect a replay attack in a speaker recognition system, at least one feature is identified in a detected magnetic field. It is then determined whether the at least one identified feature of the detected magnetic field is indicative of playback of speech through a loudspeaker. If so, it is determined that a replay attack may have taken place.

An angle sensor comprising: a plurality of magnetic field sensing elements configured to detect a magnetic field and generate a respective plurality of analog magnetic field signals; a plurality of analog frontend circuits each analog frontend circuit associated with a respective magnetic field sensing element; and a digital feedback circuit configured to generate digital magnetic field signals from the plurality of analog magnetic field signals and generate digital error correction values, wherein the plurality of analog frontend circuits are configured to obtain the digital error correction values from the digital feedback circuit, generate analog correction values from the digital error correction values, and apply the analog correction values to the plurality of analog magnetic field signals to generate a plurality of corrected analog magnetic field signals.

A magnetic sensor includes first to fourth resistors, a power supply port, a ground port, a first output port, and a second output port. The first resistor and the second resistor are located in a first region and connected in series via a first connection point connected to the first output port. The third resistor and the fourth resistor are located in a second region and connected in series via a second connection point connected to the second output port, at least a part of the second region being located at a position different from the first region in a direction parallel to an X direction. The first and second resistors are located between the third and fourth resistors in a direction parallel to a Y direction.

A calibration system for magnetometers includes magnetometers configured to measure a magnetic field to be measured; a magnetometer holder fixedly mounted on the magnetometer holder; at least one magnetic field generating device having its position fixed relative to the magnetometers, and used to generate a calibration magnetic field distribution in a space to be measured; and a calculation device configured to calculate the magnitudes of magnetic field vectors at the positions of the magnetometers according to the calibration magnetic field distribution generated by the at least one magnetic field generating device in the space to be measured, receive measured magnitudes of the magnetic field vectors from the magnetometers, and calculate detection gain values of the magnetometers on the basis of the calculated magnitudes of the magnetic field vectors and the measured magnitudes of the magnetic field vector.

According to one embodiment, a sensor includes an element part, and a control circuit part. The element part includes first and second elements. Each of the first and second elements includes a first magnetic element and a first conductive member. The control circuit part includes a first current circuit, a differential circuit, and a phase detection circuit. The first current circuit is configured to supply a first current to the first conductive member. The differential circuit is configured to output a differential signal corresponding to a difference of a first signal and a second signal. The first signal corresponds to a change in a first electrical resistance of the first magnetic element of the first element. The second signal corresponds to a change in a second electrical resistance of the first magnetic element of the second element. The phase detection circuit is configured to perform a phase detection of the differential signal.

A superconducting electronic circuit includes at least two SQUID elements, an array of at least three Josephson Junctions, and a magnetic source element. Each SQUID element has no shared Josephson Junctions or at least one shared Josephson Junction with another SQUID element and at least one exclusive Josephson Junction. The array of at least three Josephson Junctions are connected in one, two, or three-dimensions. The magnetic source element has an electrically-tunable spatially non-uniform magnetic field.

An exemplary inventive optimization model delineates a three-dimensional geometric environment for situation therein of electromagnetic sources and an electromagnetic sensor array used for measuring electric and magnetic fields emanating from the electromagnetic sources. Based on measurements and computations relating to electrical, magnetic, and structural physical properties, the geometric environment is stratified into air, sea, and seafloor regions as well as into electromagnetically distinct zones. The design of the electromagnetic sensor array is optimized through an iterative process involving successive determinations as to how well the electric and magnetic fields emanating from the electromagnetic sources may be calculated based on measurements taken in the geometric environment by the electromagnetic sensor array. Every instance of the electromagnetic sensor array in the iterative process is uniquely located and/or uniquely configured vis-à-vis every other instance. Design optimization can be performed with respect to various frequencies or frequency ranges.

Apparatus and associated methods relate to measuring position and displacement of a 2D surface magnet array of at least three adjacent magnetic north and south tracks with an acute angle versus its motion displacement relative to a magnetic field sensor (e.g., magnetic sensing probe). In an illustrative example, the geometry of the 2D surface magnet array may be planar with adjacent and alternating north and south pole regions. In some embodiments, the 2D surface magnet array geometry may take the form of (1) an axial cylindrical helical multipole magnet array having individually magnetized layers that are oriented in helical shape, or (2) a radial disk spiral multipole magnet array with at least three adjacent north and south tracks oriented as a spiral shape.

A magnetic sensor includes a piezomagnetic component which includes a first piezomagnetic element and a second piezomagnetic element that are arranged opposite to each other, a magnetostrictive component which includes a first magnetostrictive element and a second magnetostrictive element arranged opposite to each other on the same side of the first piezomagnetic element and the second piezomagnetic element, respectively, and a piezoelectric component which includes a first piezoelectric element deposited underneath the first piezomagnetic element, a second piezoelectric element deposited underneath the second piezomagnetic element, a third piezoelectric element deposited underneath the first magnetostrictive element, and a fourth piezoelectric element deposited underneath the second magnetostrictive element. The first piezoelectric element and the second piezoelectric element are electrically connected to a power supply circuit, and produce first deformation, which is applied to the first piezomagnetic element and the second piezomagnetic element to produce an alternating magnetic field.

A magnetometer system for medical use comprises one or more induction coils for detecting a time varying magnetic field. Each coil has a maximum outer diameter of 10 cm or less, and a configuration such that the ratio of the coil's length to its outer diameter is 0.9 or more, and the ratio of the coil's inner diameter to its outer diameter is 0.6 or more. Each induction coil comprises a magnetic core. The magnetometer system further comprises a detection circuit coupled to each coil and configured to convert a current or voltage generated in the coil by a time varying magnetic field to an output signal for use to analyse the time varying magnetic field.