Abstract: A single die MR array composed of a plurality of MR elements, wherein each MR element is composed of a number of serially connected MR segments. The MR elements are arranged and configured so as to produce a variety of MR array geometries. In one form, an MR array is formed to provide angular sensing schemes wherein angular measurement redundancy is incorporated therein. In a second form, an MR array is formed to provide angular sensing schemes wherein angular measurement redundancy and reference redundancy are incorporated therein.

Abstract: A sensor system for sensing a rotation of a sensing wheel is disclosed. The sensor system has a sensing coil in juxtaposition with the sensing wheel. Moreover, the sensing coil has a sensing coil output signal indicative of the rotational speed of the sensing wheel. Further, a cancellation coil is located remotely from the sensing coil and connected in series therewith. Additionally, the cancellation coil has a cancellation coil output signal indicative of an environmental disturbance which is effecting the sensing coil output signal. The cancellation coil output signal operates to cancel the effects of the environmental disturbance on the sensing coil output signal.

Abstract: A method for operating an eddy current sensor (10) with a measuring coil (2) and an evaluation circuit (4) for determining material or geometric parameters of a test object (5), in which the test object (5) is arranged at a distance (d) from the measuring coil (2). The impedance of the measuring coil (2) is evaluated, while the measuring coil (2) is being supplied with an alternating voltage of a predetermined frequency, and the evaluation circuit (4) determines the material and geometric parameters of the test object (5) based on the impedance of the measuring coil (2). The impedance of the measuring coil (2) is determined at an alternating voltage of a first frequency, and the impedance of the measuring coil (2) is determined at an alternating voltage of a second frequency, and the evaluation circuit (4) computes the material and geometric parameters of the test object (5) on the basis of the impedances of the measuring coil (2) at the first and the second frequencies.

Abstract: An angle encoder for determination of an angle between a sensor device (4, 5, 6, 7) and a magnetic field, having a magnet (2) that generates the magnetic field, a number of Hall elements (4, 5, 6, 7) disposed in the magnetic field, and flux-conducting parts (3) made of ferromagnetic material disposed between the Hall elements and rotationally fixed in relation to them, wherein the magnet (2) is embodied so that it can rotate in relation to the Hall elements and the flux-conducting parts, wherein at least four Hall elements (4, 5, 6, 7) are provided.

Abstract: A magnetic flux detector comprises a core member 12 and an armature member 11, and the core member 12 generates a magnetic flux by an exciting coil 13 when the exciting coil receives an excitation current controlled by an excitation current controller 30. The magnetic flux detector further comprises a search coil 14, which is provided in a magnetic path for the magnetic flux, and a magnetic flux calculator 40, which determines the magnitude of the magnetic flux by measuring an electromotive force induced in the search coil 14 by a change in the magnetic flux. The magnetic flux calculator 40 has a potential setup resistor 43, whose resistance B is sufficiently larger than the internal resistance A of the search coil 14 (approximately A=B/3˜B/30).

Abstract: A method is provided to determine a static position of an armature 24 of an electronically controlled solenoid device 10. The method provides an electronically controlled solenoid device having a first stator 14 and a first coil 16 operatively associated with the first stator, a second stator 18 and a second coil 22 operatively associated with the second stator, and an armature 24 mounted for movement between the first and second stators. The armature defines a magnetic circuit with each of the first and second stators and their associated coils. A flux of a magnetic circuit associated with each coil is ramped in a generally linear manner over a period of time. A nominal position of the armature is defined where current in both of the coils is substantially equal. A current slope of each of the coils resulting from the associated ramped flux is observed. An offset of each current slope from the nominal position is indicative of the static position of the armature.

Abstract: A magnetic rotational position sensor for sensing each rotational position of a control shaft about a first axis over a definable range of rotation. The position sensor generally includes a magnetic circuit and a pair of magnetic flux sensors. The magnetic circuit is comprised of a ring pole piece defining an air gap area and a magnet disposed within the air gap area. The ring pole piece and the magnet cooperate to produce a magnetic field within the air gap area. The magnetic circuit is adjoined to the control shaft to synchronously rotate the magnetic field about a second axis. The pair of magnetic flux sensors are disposed within the magnetic field to sense each rotational position of the control shaft as the control shaft is rotated about the first axis over the definable range of rotation.

Abstract: A position sensor system capable of self compensation over wide temperature ranges, air gaps and tilts. Three matched MRs are aligned in the direction of movement of a magnetic target. The middle MR is the position sensor, and the two outer MRs serve as reference sensors which sense the magnetic field at the limits of the position sensing range. The cooperating magnetic target assures that one of the two outer MR elements is always exposed to some maximum magnetic field, BMAX, corresponding to a position XMAX, and the other MR element is always exposed to some minimum magnetic field, BMIN, corresponding to a position XMIN, such that BMIN≦BX≦BMAX, corresponding to XMIN≦X≦XMAX, where BX is the magnetic field measured by the middle MR and varies with the position, X, of the target. The actual position, X, is computed assuming a linear relation between MR resistance in the magnetic field range from BMIN to BMAX and the position, X, of the target.

Abstract: A magnetic incremental motion detection system (110) for outputting a plurality of voltage and/or current signals in digital form wherein the voltage and/or current signals are a collective representation of any incremental rotational, linear, or pivotal movement of an object. A target (120) of the system (110) is adjoined to an object to synchronously move with the object. A plurality of indications (121c, 121d) are adjoined to the target (120), and uniformly and serially disposed along an area (121a) of a surface (121) of the target (120). The system further comprises one or more magnetic sensors (80, 180) spatially positioned from the area of the surface to define air gap areas therebetween. Each of the magnetic sensors (80, 180) are operable to output an analog signal in response to a synchronous movement of the target with the object, and one of two digital circuits (85, 185) output a digital signal in response to the analog signal.

Abstract: A self-compensating control circuit for use with a magneto-resistive sensor. The control circuit includes a first stage amplification and offset function that removes a DC component from the input signal and maximizes an AC component of the input signal within the dynamic range of the control circuit. Subsequent stages remove the remaining DC component, if any, and provide suitable additional amplification. A comparator provides a digital output based on the processed input signal and a threshold signal.

Abstract: A magnetic sensor with a signal processing circuit includes a magnetic sensor section 4 composed of a compound semiconductor thin film or a magnetic thin film, and a signal processing circuit 5 for amplifying a magnetic signal the magnetic sensor section detects as an electrical output. The signal processing circuit 5 includes an operational amplifier 51 and a constant current circuit 52 for carrying out feedback. The constant current circuit 52 in the signal processing circuit 5 includes a plurality of resistors with two or more different temperature coefficients, and the current output from the constant current circuit has a temperature coefficient inversely proportional to the temperature coefficient of the combined resistance of the plurality of the resistors.

Abstract: A magnetically sensitive sensor for counting pulses for measuring rotational speeds and angular positions of a rotating component via a pulse transmitter connected for rotating with the rotating component automatically adapts its switching points to the respective measurement location conditions. A logic unit initiates automatic adaptation of the switching points from an original state when an operating parameter first exceeds a limit value after the supply voltage of the sensor turned on. The original state is not preset or is coarsely preset. The configuration of the switching points is then stored in a non-volatile data memory specifically for the sensor.

Abstract: A magnetic level sensor is adapted for interconnecting with a vertically moving component of a vehicle such that the level sensor determines a vertical orientation of the component of the vehicle relative to the frame or chassis of the vehicle. The magnetic level sensor includes a magnetic angular measurement device interconnected to the component of the vehicle such that vertical movement of the component causes a corresponding relative rotational movement of a magnetic element associated with the angular measurement device. An electronic control is included for analyzing an output of the angular measurement device and determining an angle of rotation of the magnetic element and thus a vertical movement of the component. The control further determines an error or offset in the output of the angular measurement device and adjusts an output of the control in response to the error or offset.

Abstract: A detection system determines the position of an object moving along a first direction. The system includes a magnetic field source generating a magnetic field signal and a magnetic field detection system coupled to the object. The detection system includes a source interface module with magnetic field sensors positioned a known distance apart along a second direction different from the first direction. Each sensor detects the magnetic field generated by the magnetic field source and generates a magnetic field signal. A processing module processes the magnetic field intensity signal produced by the source interface module. The processing module generates data for each sensor in the source interface module, which is made up of points representing peak magnetic field and sensor location along the second direction. The points are compared to determine the distance of the object from the magnetic field source along the second direction.

Abstract: Disclosed is a method of obtaining information in-situ regarding a film of a sample using an eddy probe during a process for removing the film. The eddy probe has at least one sensing coil. An AC voltage is applied to the sensing coil(s) of the eddy probe. One or more first signals are measured in the sensing coil(s) of the eddy probe when the sensing coil(s) are positioned proximate the film of the sample. One or more second signals are measured in the sensing coil(s) of the eddy probe when the sensing coil(s) are positioned proximate to a reference material having a fixed composition and/or distance from the sensing coil. The first signals are calibrated based on the second signals so that undesired gain and/or phase changes within the first signals are corrected. A property value of the film is determined based on the calibrated first signals. An apparatus for performing the above described method is also disclosed.

Abstract: A sensor unit is supported on a stationary ring which does not rotate even when it is in use, and the rotation of the rotary ring can be detected by a rotation detecting sensor held within the sensor unit. Within the sensor unit, besides the rotation detecting sensor, there are disposed other sensors such as a temperature sensor and a vibration sensor, thereby being able to detect the rotation speed and the rotation number of the wheel supported on the rotary ring, and the other car driving conditions.

Abstract: A proximity sensor for determining the gap between a sensor and a metal target which is insensitive to noise, changes in temperature of the sensor and different lengths of wire by measuring the AC conductance, DC conductance and susceptance of the sensor and using the measured values with a predetermined data base to derive the desired gap distance.

Abstract: A sensor module (1) is constructed as a solid state integrated circuit (IC) and has a sensor (2) as well as at least one measuring amplifier (3), wherein the sensor module has external connections at least for the power supply and for the output measurement signal. In the sensor module an evaluation circuit (6) is provided that is connected to at least one internal measurement point of the circuit. The evaluation circuit (6) is connected to a modulator (10) for modulation of the supply current and/or the supply voltage and/or the output measurement signal, in order to output a diagnostic signal, which is formed from an internal circuit measurement value, via the available external connections of the sensor module.

Abstract: A circuit and method of providing desired response from magnetic field sensors to a predetermined magnetic function. Typically, magnetic field sensors, such as magnetoresistive devices and Hall effect sensors, provide an output which is a characteristic function of the magnetic field density, and so they do not generate a linear response in relation to any predetermined magnetic function, such as is required within numerous position or angle resolving circuits. The present invention utilizes two or more magnetically sensitive devices to tailor the overall sensor output signal to any desired function of the magnetic field density. The devices are connected in such a way that they mutually effect each other's voltages or currents to render the final desired output characteristic.

Abstract: The present invention provides a position sensor which is suitable for use in a piston and cylinder assembly. The position sensor includes a movable field modifying member which is operable to vary the inductance of a sensor winding, whereby the position of the field modifying member relative to the sensor winding can be determined by monitoring the inductance of the sensor winding. The position sensor also includes a compensation winding which is arranged to have a common coupling with the field modifying member whereby a signal output from the compensation winding can be used to compensate for variations in the signal level output by the sensor winding caused by, for example, temperature variations of the system.

Abstract: A position sensor system capable of self compensation over wide temperature ranges, air gaps and tilts. Three matched MRs are aligned in the direction of movement of a magnetic target. The middle MR is the position sensor, and the two outer MRs serve as reference sensors which sense the magnetic field at the limits of the position sensing range. The cooperating magnetic target assures that one of the two outer MR elements is always exposed to some maximum magnetic field, BMAX, corresponding to a position XMAX, and the other MR element is always exposed to some minimum magnetic field, BMIN, corresponding to a position XMIN, such that BMIN≦BX≦BMAX, corresponding to XMIN≦X≦XMAX, where BX is the magnetic field measured by the middle MR and varies with the position, X, of the target. The actual position, X, is computed assuming a linear relation between MR resistance in the magnetic field range from BMIN to BMAX and the position, X, of the target.

Abstract: An improved method of measuring vehicle speed based on the output signal of a variable reluctance speed sensor responsive to the teeth of a transmission output gear adjusts the sensitivity of a signal processing circuit in dependence on the mode of operation of the vehicle so as to reduce sensitivity to output signals produced by gear tooth vibration. The signal processing circuit only passes portions of the sensor output signal that have an amplitude greater than a predefined threshold and a frequency less than a predefined frequency, except when an electronic controller identifies a condition of potentially erroneous speed sensing characterized by substantially stationary vehicle operation with the engine decoupled from the output gear and an engine speed in excess of a calibrated threshold.

Abstract: A reduced offset absolute position transducer has at least one magnetic field generator that generates a first changing magnetic flux in a first flux region. A plurality of coupling loops have a first plurality of coupling loop portions spaced at a first wavelength along a measuring axis and a second plurality of coupling loop portions spaced at a second wavelength along a measuring axis. One of the first plurality of coupling loop portions and the second plurality of coupling loop portions are inductively coupled to a first changing magnetic flux from a transmitter winding in a first flux region to generate a second changing magnetic flux outside the first flux region in the other of the first plurality of coupling loop portions and the second plurality of coupling loop portions. A magnetic flux sensor is positioned outside the first flux region and is responsive to the second changing magnetic flux to generate a position-dependent output signal.

Abstract: Methods and apparatus for position/orientation tracking within a bounded volume employ at least one stationary sensor, called a “witness sensor,” having a fixed position and orientation near or within the volume to account for electromagnetic distortion. One or more probe sensors are placed on an object to be tracked within the volume, and the output of each witness sensor is used to compute the parameters of a non-real effective electromagnetic source. The parameters of the effective source are used as inputs to the computation of position and orientation as measured by each probe sensor, as if the object were in the non-distorted electromagnetic field produced by the effective source or sources. In addition to trackers for helmet-mounted displays in aircraft, tank, and armored-vehicle applications, the invention finds utility in any electromagnetic tracking system which might be subject to electromagnetic distortion or interference.

Abstract: An electronic position sensor for determining position as a function of magnetic flux density. The position sensor includes a magnetic flux sensor and a movable magnet, the sensed magnetic flux density by the magnetic sensor being a function of the relative air gap, magnet thickness, and magnetic field direction between the magnet and the magnet sensor element. The relationship between the magnetic flux density sensed by the magnetic sensing element and the positional disposition of the moved magnet component of the sensor is geometrically defined and optionally linear between two defined points of the range of articulation or motion of the sensor. The magnetic flux sensing element is a Hall-effect integrated circuit, magnetoresistor, magnetodiode, magnetotransistor, or similar sensing element with associated electronic circuitry having adjustable or programmable features including ratiometry, gain, offset voltage, temperature coefficient, and output signal range limiting.

Abstract: An apparatus for minimizing angular rotor position errors in an air core gauge includes an air core gauge (105) having a magnetic rotor (108) and at least three coils (102, 104 and 106) wound around the rotor (108). A probe signal is applied to the first coil (102), and output signals are developed and detected across the second and the third coils (104, 106) in response to the probe signal and low-frequency signals applied to one or more of the coils (102, 104 and 106). The output signals are processed by a demodulation circuit (110) and a number of DC voltage signals are produced therefrom. A control circuit (304) is responsive to the number of DC voltage signals to determine an actual angular position of the rotor (108), and to suitably adjust the low-frequency signals to thereby correct for errors between the actual angular position of the rotor (108) and the desired angular position thereof.

Abstract: Electromagnetic field mapping is accelerated by acquiring data from the surface bounding a volume of interest and solving the boundary value problem (BVP) using Green's function in a preferred embodiment. Instead of measuring electromagnetic field components on a step-by-step basis at each point within a region of interest, only a component of the field, preferably the normal component, is measured on the surface bounding the volume. The use of surface data acquisition, a solution to the BVP using Green's function, and optional error correction based on the treatment of errors as virtual sources, combine to produce a process of defining of the electromagnetic field within the volume that reduces to a few minutes what presently takes days or longer, and sometimes impossible.

Abstract: A solution to the electromagnetic position/orientation tracking problem is presented in an environment wherein strong electromagnetic distortion may be present includes at least one source of an AC electromagnetic field, at least one witness sensor measuring components of the electromagnetic induction vector at known spatial points close to, or within the volume of interest, at least one wireless probe sensor placed on the object being tracked, and a control and processing unit. The wireless sensor has a known response or distortion to the electromagnetic field generated by the primary source. The control/processing unit uses data from the witness sensor(s) to locate the probe sensor, treating the probe sensor as a secondary source of the AC electromagnetic field; that is, as a transponder with initially known magnetic parameters.

Abstract: An inductive angle sensor with an exciting coil and several receiving coils displaced with respect to each other by a predetermined angle. A rotor element, a position of which is to be determined by the angle sensor, has an inductive coupling element that couples signals into the receiving coils which are essentially sinusoidally affected by the position of the rotor element. Output signals of various receiving coils are phase-shifted with respect to each other. In order to establish a linear interrelationship between the position of the rotor element and the sensor output signals, on the one hand, and to achieve a greatest possible measurement accuracy, on the other hand, the angle sensor has a selection device that selects to evaluate a respective output signal whose nearly linear part of its sine function is in a vicinity of its zero crossing.

Abstract: A system including a pulse-generating device can comprise of at least one analog sensor and at least one unit for signal-processing is arranged to detect the analog signal and to generate signal changes having a higher frequency. When generating signal changes in connection with the determination of the amount of fuel dispensed from a fuel pump unit and a frequency generator for generating a periodic analog signal having a frequency is generated, which corresponds to a fuel volume flow in the pump unit. The amplitude of the analog signal is detected and then signal changes having a higher frequency are emitted, which is dependent on and higher than the frequency.

Abstract: A position sensing device including two spaced conductive coils constituting a primary and secondary winding of a transformer. A coupling member is mounted to a moveable object. This movement adjusts or alters the transformer coupling between the primary and the secondary and produces a variable output signal which can be correlated to the position of the moveable member. An electronic module is coupled to a programmable controller and adjusts an output from the linear position sensor to linearize the output with relative movement of first and second members such as components of a vehicle shock absorber.

Abstract: The sensor circuit arrangement includes a sensor (23; 53) that produces an alternating voltage sensor signal that varies according to a measured variable; first and second current supplying circuits (21, 51) connected to respective sensor terminals to apply first and second output voltages (U1, U2) to the respective terminals; a counter-coupling network (24, 54) coupling the current supplying circuits to provide respective constant currents to the sensor (23, 53) and a sensor signal processing circuit portion. The sensor signal processing circuit portion includes an operational amplifier (13,46) connected across the sensor terminals, a low-pass filter (20,50) connected to the operational amplifier and a capacitor (19, 46) connected to the operational amplifier to generate an alternating output signal having an amplitude depending on the magnitude of the measured variable. The low-pass filter produces a filter output signal indicative of a temperature-dependent internal sensor resistance.

Abstract: A measurement transducer and method is provided which provides a pair of pulses as an output, the measured condition being represented by the time between the pulses, and which includes internal compensation such that the pair of pulses are adjusted to mimic the output of a predetermined ideal transducer. In one embodiment, correction factors are calculated for a magnetostrictive linear position transducer by comparing the transducer output with a position measurement taken by a separate measuring device. These correction factors are stored in a non-volatile memory. Then, during operation of the transducer, a correction factor is selected for each uncorrected measurement and added to the uncorrected measurement to provide a compensated measurement. The compensated measurement is then used to generate a time value using a calculation which includes a predetermined standard waveguide propagation velocity value.

Abstract: A magnetic incremental encoder includes a plurality of detection devices which are provided on an outer periphery of a rotational member at a predetermined phase difference, wherein each of the detection devices outputs signals which vary periodically in accordance with the rotational angle of the rotational member upon rotation thereof; wherein the plurality of detection devices are provided in sets of two detection devices on the outer periphery of the rotational member, wherein a phase difference between one of the sets of two detection devices and an adjacent another of the sets of two detection devices is determined according to the following formula:

Abstract: The invention describes methods for locating a treatment device disposed within a living body by means of magnetic fields that are produced by Barkhausen jumps, principally from amorphous tag wires with high permeability that exhibit reentrant flux reversal. When wires of this type are attached to concealed treatment devices such as catheters, interrogation or scanning of the tag wire by a low frequency ac magnetic field affords an accurate means for locating the treatment devices using a sensor coil to detect the magnetic field signal from the wire locating tag. The strength of the field detected by the position of a sensor coil with respect to the locator tag is used to determine the location of the tag. A favorable signal to noise detection ration is obtained as the signal emitted by the wire is at a very high frequency compared to that of the frequency of the interrogation field.

Abstract: An inductive proximity sensor that uses a resonant oscillatory circuit to detect a target by changes to inductive reaction. The oscillating circuit has primary and secondary windings where a capacitor and load resistance are connected in parallel with the primary winding, the value of the load resistance is selected so that in a state of oscillation the ohmic losses in the load resistance are substantially higher than the ohmic losses in the primary winding, and the primary and secondary windings are disposed so that the mutual flux between the primary and secondary windings is substantially less than the particular flux of each winding.

Abstract: An inductive absolute position sensor has at least one magnetic field generator that generates a first changing magnetic flux in a first flux region. A plurality of coupling loops have a first plurality of coupling loop portions spaced at an interval related to a first wavelength along a measuring axis and a second plurality of coupling loop portions spaced at an interval related to a second wavelength along a measuring axis. One of the first plurality of coupling loop portions and the second plurality of coupling loop portions are inductively coupled to a first changing magnetic flux from a transmitter winding in a first flux region to generate a second changing magnetic flux outside the first flux region in the other of the first plurality of coupling loop portions and the second plurality of coupling loop portions. A magnetic flux sensor is positioned outside the first flux region and is responsive to the second changing magnetic flux to generate a position-dependent output signal.

Abstract: There is provided a highly reliable rotation sensor which is capable of accurate detection of a rotation state. The rotation sensor comprises: a rotor rotating together with a rotation portion of a detection side; a first supporting member for rotatably supporting the rotor; and a detecting member secured to the first supporting member for detecting a rotation state of the rotor. The first supporting member is supported movably in both directions, that is, an X direction orthogonal to the direction of the rotating shaft of the rotor and a Y direction which is orthogonal to the direction of the rotating shaft of the rotor and orthogonal to the X direction.

Abstract: A magnetic bearing device has an electromagnet for levitating an object under electromagnetic forces, a displacement sensor for detecting the displacement of the levitated object, a controller for supplying a signal to the displacement sensor through a cable and a current to the electromagnet through a cable, and a protective plate of nonmagnetic metal material disposed between the displacement sensor and the levitated object. The controller includes a levitation control system having a noise removing filter for preventing an abnormal signal caused by the protective plate from being applied to the displacement sensor.

Abstract: A method of compensating periodic error signals in sensor output is provided. The method comprises obtaining a sum signal from sensing outputs of M sensor elements (where M is a positive integer), obtaining the amplitude and phase of N frequency components included in the sum signal, and calculating a sensing output gain adjustment coefficient for each sensor output. To ensure that a sum signal level obtained by summing a pre-adjustment output of each sensor element multiplied by the gain adjustment coefficient equals a sum signal level obtained by summing the unmodified outputs of the sensors, a gain adjustment coefficient is obtained for each sensor output by using a calculated scaling coefficient to perform pre-adjustment scaling of each gain adjustment coefficient. The adjustment gains thus obtained are used to adjust the gain of each sensor output.

Abstract: A pedal stroke sensor a rotor that rotates with a brake pedal with a pair of brushes fixed on the rotor. The brushes are inclined oppositely to each other along rotating direction of the rotor and contact a circuit printed on a circuit board to generate output voltages V1A and V1B which increase and decrease oppositely to each other in response to the brushes sliding over the circuit board. A difference signal |V1A−V1B| is output as a signal corresponding to pedal stroke S of the brake pedal. When any kind of vibration changes the contacting positions of the brushes on the board, the output voltages V1A, V1B change in the same direction, so that, even if the contacting positions of the brushes change because of a vibration, the difference signal |V1A−V1B| does not change greatly, allowing accurate detection of the position of the brake pedal even if such vibrations occur.

Abstract: A rotational sensing assembly including a ferromagnetic sensor wheel rotationally fixed to a shaft having a tooth pattern including a missing tooth. An inductive sensor is mounted adjacent the periphery of the sensor wheel and in communication with a processor. The sensor produces a generally sinusoidal signal in response to the wheel rotation, with voltage zero crossings that are time stamped by the processor. The geometry of the sensor wheel around the missing tooth location is altered to equalize the induced voltage in the sensor for fixed time intervals in order to maintain proper timing of the zero crossings in the sensor signal.

Abstract: A method for determining position and/or direction of a target, where the target has a series of magnetic poles with a magnetic pole spacing d.

Abstract: For the offset calibration of a magnetoresistive angle sensor for the determination of the directions of magnetic fields, the sensor includes a Wheatstone bridge with at least four magnetoresistive resistors. The Wheatstone bridge receives an input signal at its input side, in particular an input voltage, and supplies an angle signal at its output side, in particular an angle voltage, in dependence on the direction of a magnetic field which acts on the Wheatstone bridge. The Wheatstone bridge includes a first and a second pair of mutually opposed, substantially parallel magnetoresistive resistors, the first and the second pair being arranged substantially at right angles to one another, while the direction of the magnetic field can be determined from the angle signal supplied by the Wheatstone bridge by means of an evaluation circuit.

Abstract: A magnetoresistive sensor for use in detecting relative motion between the sensor and a further object bearing an alternating pattern of north/south magnetic poles. The sensor includes one or more pairs of magnetoresistive elements positioned so that each element within a pair magnetically complements the corresponding element in that pair. That is, whenever an element is exposed to a north pole of the magnetic pattern, a corresponding complementary element is exposed to a south pole so as to provide a magnetically complemented output. Such pair of complementary magnetoresistive elements are connected into a bridge circuit such that jitter effects caused by asymmetric magnetic fields and physical differences between sensor elements are cancelled. The quadrature sensor output is frequency multiplied to provide frequency multiplied output signals in quadrature.

Abstract: A proximity detector for sensing a magnetic field includes a magnetic-field-to-voltage transducer for generating a signal voltage Vsig that is proportional to the magnetic field, a peak-to-peak percentage threshold detector coupled to the magnetic-field-to-voltage transducer to receive the signal voltage Vsig and for providing an output signal voltage Vout and a forcing circuit coupled to the peak-to-peak percentage threshold detector for forcing and maintaining the value of the output signal voltage Vout at a predetermined value during an initial startup interval of the proximity detector. The proximity detector may further include an automatic gain control circuit coupled to the forcing circuit to provide a proximity detector capable of operating in a peak-to-peak percentage threshold detector mode with automatic gain control.

Abstract: An interleaved parallel MR bridge array is optimized for sensing fine pitch ring magnets and can be utilized to reduce ring magnet target size for wheel speed sensing applications.

Abstract: A method and apparatus wherein a single dual element galvanomagnetic sensor, herein exemplified by a single dual element magnetoresistive sensor (16′), is utilized to sense crankshaft position and rotational speed from the passage of single tooth edges (12′) of a target wheel (10′) by continuous adaptive matching of both MR output signals (VMR1′, VMR2′) during sensor operation. Over a slot (28′) or tooth (26′), both MR output signals should be equal, and if not, they are matched by adjusting the current of one of the current sources (30′, 32′) driving the MRs, performed over a slot or a tooth. Due to higher magnetic sensitivity at smaller air gaps, matching by current adjustment over a tooth is preferred. In a preferred embodiment of the present invention, one MR is driven by a constant current source (30′) while the other MR is driven by a voltage controlled current source (32′).

Abstract: In an evaluation circuit for evaluating an output signal of a magnetoresistive sensor (1) for rotational speed measurement, in which the evaluation circuit performs an offset compensation of the sensor signal and comprises a comparator (4) which receives the offset-compensated sensor signal and compares it with a reference voltage, a reliable identification of the output signal of the sensor after switching on the arrangement is ensured in that, in an initial mode, the value of the reference voltage is selected in dependence upon the temperature, the temperature dependence being approximated to that of the sensor signal, in that a control unit (6) is provided which, in the initial mode, consecutively checks whether the sensor signal is present, triggers the offset compensation only after the presence of said signal, subsequently checks whether the comparator (4) supplies an output signal, and changes over to a control mode only after the presence of said signal, in which control mode the temperature dependenc

Abstract: The rotation position of a rotor (2) rotatable around a rotation axis (1) is determined by mounting a magnetic source (2.1) on the rotor, by providing on a stator (3) at least three sensors (4, 5, 6, 7) for measuring the magnetic field of the magnetic source and being arranged in at least two pairs (4/5, 6/7), calculating the difference of quantities measured by the two sensors of each sensor pair, calculating the ratio of the difference values of two pairs and comparing the ratio with a predetermined function of said ratio versus the rotation position. This rotation position determination is very robust against offset and sensitivity variations common to all sensors (4, 5, 6, 7) and against external magnetic fields and can easily be made robust against mechanical tolerances between rotating and stationary parts also. In a preferred embodiment, there are four sensors (4, 5, 6, 7) arranged at the corners of a square perpendicular to and symmetrical relative to the rotation axis (1).