There is provided an optical encoder including a phase shifter circuit, two multiplexers, two digital circuits and four comparators. The phase shifter circuit receives signals from an amplifier and outputs multiple phase shifted signals. Each of the two multiplexers receives a half of the multiple phase shifted signals and outputs two pairs of phase shifted signals, each pair having 180 degrees phase difference, respectively to two comparators connected thereto. Each of the two digital circuits controls the corresponding multiplexer to select the two pairs of phase shifted signals from the half of the multiple phase shifted signals.

Systems, methods and apparatuses for magnetic field sensors with self-test include a detection circuit to detect speed and direction of a target. One or more circuits to test accuracy of the detected speed and direction may be included. One or more circuits to test accuracy of an oscillator may also be included. One or more circuits to test the accuracy of an analog-to-digital converter may also be included. Additionally one or more IDDQ and/or built-in-self test (BEST) circuits may be included.

A method for determining the angle of the rotor of an electric motor includes receiving a first rotor position signal from a rotor position sensor by using a control unit, the first rotor position signal including a plurality of orders; determining the angular velocity of the electric motor at least by way of the first rotor position signal by using an angular velocity module of the control unit; determining a first base signal by way of the determined angular velocity and the first rotor position signal by using a first filter module of the control unit; and determining the angle of the rotor at least by way of the determined first base signal by using an angle module of the control unit.

To provide an angle detection apparatus which can reduce the error of the angle which is caused by the eccentricity, by performing the reduction processing about smallest possible number of frequency bands and the lowest possible order of frequency band. An angle detection apparatus performs a first-order component reduction processing which reduces a first-order component which is a component of one rotation period in a mechanical angle of the rotor, to each of the first system two output signals; and calculates a first angle (θ1) of the rotor, based on the first system two output signals to which the first-order component reduction processing was performed.

A controller (1) to reduce integral non-linearity errors of a magnetic rotary encoder (2) comprises a position error determining unit (20) to determine a plurality of time marks (P0, . . . , Pk) specifying a respective time at which a moving device (3) reaches a respective one of predefined positions (α0, . . . , αk). The position error determining unit (20) calculates a plurality of error correction parameters (B[0], . . . , B[k]) in dependence on the time marks (P0, . . . , Pk). An error compensation unit (10) of the controller determines a respective error compensated position parameter (φ.sub.start.sub._comp, φ0_comp, . . . , φn_comp) for each position parameter (φ.sub.start, φ0, . . . , φn) received from the encoder (2) in dependence on the respective position parameter (φ.sub.start, φ0, . . . , φn) and the respective error correction parameter (B[0], . . . , B[k]).

A dynamic displacement error compensation system by which detection error information obtained based on calibration detection of first and second axes, is respectively made into first and second compensation tables for compensating displacement on the axes by using positional information of the axes as variables, the first compensation table is stored in a first driver of a first motor device for driving a first moving element to move linearly on the first axis, the second compensation table is stored in a second driver of a second motor device for driving a second moving element to move linearly on the second axis, the drivers simultaneously or successively obtain a first dynamic positional information of the first moving element on the first axis and a second dynamic positional information of the second moving element on the second axis, and the moving elements are respectively displaceably compensated according to the compensation tables.

A position sensing device for measuring a position, comprises a position sensing device for measuring a position; a plurality of sensors arranged to produce sense signals each being a function of an input phase representative of a position to be measured; a combiner circuit arranged to generate an error signal by combining the sense signals according to an array of weight factors; a processing block including a loop filter to filter the error signal and arranged to output a phase value representative of the position; and a feedback loop comprising a feedback signal unit arranged for receiving the output phase value and for adjusting based on the received output phase value of the array of weight factors.

An n-th-harmonic error estimation unit that estimates the error component of an n-th harmonic included in a resolver angle 8 and a subtraction unit that subtracts an n-th-harmonic estimated angle error from θ to output the corrected angle θ′ are included. The n-th-harmonic error estimation unit includes an n-th-harmonic error phase detection unit that obtains a phase difference u such that the integral, for a 1/n period of an electrical angle of the rotor, of the output obtained by synchronously detecting 0 by using a rectangular wave obtained by comparison from a COS wave expressed as cos(nθ+u) becomes zero and generates a SIN wave expressed as sin(nθ+u); a synchronous detector that synchronously detects θ′ by using a rectangular wave obtained by comparison from the SIN wave; an integrator that integrates the detected output for a 1/n period of the electrical angle; an actual angle integral calculation unit; an amplitude setter that sets an error amplitude from the value obtained by subtracting the integral of the actual angle integral calculation unit from the integral of the integrator; and a multiplier that generates the n-th-harmonic estimated angle error by multiplying the SIN wave by the error amplitude.

The invention relates to a counting sensor for counting the number of rotations or of linear displacements of an object, wherein the counting sensor comprises: one single Wiegand module; at least one sensor element; a processing electronic circuit, which is connected to the sensor element; and a permanent magnet arrangement, which is movable relatively to the Wiegand module; wherein the processing electronic circuit is configured to obtain direction information, whether the permanent magnet arrangement moves in said one direction or in an opposite direction, and (ii) to obtain magnetic pole information; and a data storage for storing a value, which indicates the number of the rotations or of the linear displacements; wherein: the processing electronic circuit is configured (i) to determine, on the basis of the direction information and the magnetic pole information, the number of the rotations or of the linear displacements of the object and to store the corresponding value in the data storage, (ii) to perform, on the basis of a sequence of the direction informations and of the magnetic pole informations, an error detection to the effect whether one of the rotations or one of the linear displacements of the object has not been recognized partially or completely, and (iii) to determine an according correction and to correct the value upon detection of an error.

A monitoring control device for diagnosing a presence/absence of a detection failure of a rotation state of a rotator includes: a rotation sensor that detects the rotation state of the rotator and outputs an analog signal in response to the detected rotation state; a converter that calculates a first absolute angle of the rotator at a first timing based on the analog signal and outputs a signal including the first absolute angle; a first control device 10 that obtains the first absolute angle; and a second control device 20 that calculates a second absolute angle of the rotator at a second timing different from the first timing based on the analog signal. The first control device 10 generates a first diagnostic signal based on the first absolute angle, and outputs the first diagnostic signal to the second control device. The second control device generates a second diagnostic signal based on the second absolute angle, and compares the first diagnostic signal with the second diagnostic signal to diagnose the presence/absence of the detection failure of the rotation state.