A rotary encoder that is capable of securing a sufficient synthesis tolerance while achieving miniaturization is provided. The rotary encoder 1 includes a rotor 3, a stator 4, and a calculating unit 5 for calculating the rotation angle. The rotor 3 has a first rotor pattern 31 with a plurality of unit patterns 310 arranged along the measurement direction around the rotating shaft 2, and a second rotor pattern 32 with fewer unit patterns 320 than the plurality of unit patterns 310 in the first rotor pattern 310 arranged along the measurement direction. The number of the plurality of unit patterns 310 of the first rotor pattern 31 and the number of the plurality of unit patterns 320 of the second rotor pattern 32 are provided such that the maximum common divisor therebetween is two or more. The calculating unit calculates the rotation angle of the rotor 3 based on the detection signals from the first rotor pattern 31 and the second rotor pattern 32.

A scale includes a base material, an intermediate layer of soft magnetic material formed on one surface of the base material and roughened on face thereof opposite to the base material, and a scale pattern of a conductor formed on the intermediate layer.

A feedback device for use in a gas turbine engine, and methods and systems for controlling a pitch for an aircraft-bladed rotor, are provided. The feedback device is composed of a circular disk and a plurality of position markers. The circular disk is coupled to rotate with a rotor of the gas turbine engine, to move along a longitudinal axis of the rotor, and has first and second opposing faces defining a root surface that extends between and circumscribes the first and second faces. The plurality of position markers extend radially from the root surface and are circumferentially spaced around the circular disk. The position markers have a top surface elevated with respect to the root surface and opposing first and second side surfaces. The side surfaces of the position markers have a curved concave profile extending toward the root surface.

Apparatus and methods provide sensing of quadrants, angles, or distance using magnetoresistive elements. A quadrant or angle sensor can have magnetoresistive elements split into multiple angles to generate an output with reduced harmonics. A distance sensor can have magnetoresistive elements split and spaced apart to generate an output with reduced harmonics. A biasing conductor can alternatingly carry different amounts of current (different in at least one of magnitude or direction) for DC offset compensation or cancellation.

A linear or angular position sensor system comprising a magnetic structure for generating a magnetic field, and a sensor device movable relative to the magnetic structure. The sensor device comprises a plurality of sensor elements for measuring at least two characteristics of said magnetic field, and a processing circuit for determining a linear or angular position of the sensor device relative to the magnetic structure in accordance with a predefined function of these characteristics (e.g. components or gradients). The magnetic structure comprises one or more grooves, having a shape and size which can be described by a limited set of parameters, having values optimized to reduce a maximum error between the actual position of the sensor device, and the calculated position based on said predefined function, by at least a factor of 2.

A position-measuring device includes a scale having first and second measuring graduations, which each include graduation structures that respectively extend parallel to first and second directions. A first scanning unit is associated with the first measuring graduation, and second and third scanning units are associated with the second measuring graduation. A fourth scanning unit is associated with the first or second measuring graduation. In the former case, a first straight connecting line running through scanning locations of the first and fourth scanning units and a second straight connecting line running through scanning locations of the second and third scanning units are parallel or form a predetermined angle therebetween that is not equal to a sum of the angles of the first and second directions. In the latter case, the scanning locations of the second, third and fourth scanning units do not lie on a common straight connecting line.

A magnetic encoder comprising an encoder element having at least two tracks of encoder regions, each region comprising a magnetic pole, the poles along each track being arranged as an alternating pattern of North and South poles, and one or more sensors, each sensor comprising one or more sensing elements associated with a respective track and generating an output that is indicative of the magnetic field associated with that track in the vicinity of the sensor, in which at least one track has a differing number of poles to at least one of the other tracks, and in which the properties of the poles of a first one of the tracks differ along the track such that there is a periodic variation along the first track of the magnetic field emitted by the first track that is detected by the sensing elements associated with the first track which at least partially cancels out a corresponding periodic variation in field from the other tracks that is also detected by the sensing elements associated with the first track.

A magnetic encoder having a plurality of rows of magnetic tracks and capable of detecting an absolute angle is easily producible with higher accuracy. The magnetic encoder includes: a core member of annular shape having a bending plate portion that bends and extends from an edge of a track formation surface; and two or more rows of magnetic tracks arranged adjacent to each other on a magnetic member provided on the track formation surface, each track having N poles and S poles alternately magnetized thereon. The magnetic tracks include a main track that has a largest number of magnetic poles and is used for calculating an angle, and a sub track used for calculating a phase difference from the main track. The main track is located on a side closer to the bending plate portion than the sub track.

A position sensor includes a detector and a signal processor. The detector includes a magnet generating a bias magnetic field and a detection element configured to be applied by the bias magnetic field, and generates plural detection signals including distinct phase difference and corresponding to plural ranges aligned in one direction along a movement direction of a detection target, based on a change in a magnetic field received by the detection element from the detection target with a movement of the detection target having a magnetic body. The signal processor acquires the detection signals from the detector, compares the detection signals with a threshold value, and specifies a position of the detection target as a position at one of the ranges based on a combination of magnitude relation between the detection signals and the threshold value.

A position detection encoder includes a scale that has a position detection pattern and a linear pattern that is formed in a direction parallel to a length direction of the position detection pattern; and a position detector generating a position detection signal with a different value due to a displacement of the position detection pattern in the length direction. In the position detector, a position confirmation pattern is formed that includes two markers arranged at an interval equal to or less than an offset tolerance value for a positional relationship of the position detector and the scale in a width direction of the position detection pattern.