An absolute position measurement system includes a multipole magnet including alternating magnetic poles extending along a multipole extension direction, the multipole magnet has a linear changing configuration relative to a linear path and produces a magnetic field having a field strength that undergoes a sinusoidal change along the linear path due to the alternating magnetic poles and a linear change along the linear path according to the linear changing configuration relative to the linear path; and a magnetic sensor configured to move along the linear path. The magnetic sensor includes a first sensor element arrangement configured to generate a first sensor signal, a second sensor element arrangement configured to generate a second sensor signal that is phase shifted with respect to the first sensor signal, and a processing circuit configured to calculate an absolute position of the magnetic sensor based on the first sensor signal and the second sensor signal.

A rotary coding disc and a method for designing the same is applied to an optical encoder. N-bit De Bruijn sequences include 1 and 0. The N-bit De Bruijn sequence has the maximum binary code and the minimum binary code. When a binary code having M bits is located between the maximum binary code and the minimum binary code, the corresponding N-bit De Bruijn sequences are selected as diagonal De Bruijn sequences, wherein

[00001]$\frac{2^N-2N}{2}-\frac{N}{2}<M<\frac{2^N-2N}{2}+\frac{N}{2}.$

The De Bruijn sequence may be converted into a De Bruijn energy level. The total number of 1 consecutively neighboring 0 and (N−1) consecutively neighboring N of the De Bruijn energy level is calculated. The transparent areas and the opaque areas are located based on the De Bruijn sequence or the De Bruijn energy level that corresponds to the total number less than or equal to N.

The present disclosure provides a magnetoresistive quadrant detector for use in a magnetic sensing device comprising a magnetic multi-turn sensor and an angle turn sensor, in particular, an angle sensor configured to provide 180° absolute angle measurements, such as an anisotropic magnetoresistive (AMR) angle sensor. The quadrant detector is formed of at least two magnetoresistive elements, preferably giant magnetoresistive (GMR) elements, which may be integrated to the multi-turn sensor die or provided on a separate die within the sensor package. The magnetoresistive elements are configured to provide a unique combination of resistance states for each quadrant of magnetic field direction. This quadrant information can then be used to remedy any ambiguities in the multi-turn measurement without needing 360° absolute angle information from the single turn angle sensor.

An inductive angle sensor includes an exciter coil, an oscillator circuit, a plurality of receiver coils, an evaluation circuit evaluating a plurality of signals induced in the receiver coils, and a coupling element that is movable and influences a strength of an inductive coupling between the exciter coil and the receiver coils. The coupling element has a first encoder element and a second encoder element. The coupling element has a third encoder element formed as a conducting extension with an asymmetric geometry. The asymmetric geometry influences the strength of the inductive coupling between the exciter coil and the receiver coils only in a part of a plurality of periodically repeating loop structures of the receiver coils.

A sensor arrangement for an absolute measuring position detection system based on a magnetic code object has a substantially linear arrangement of magnetic field sensors, wherein a bit pattern encoded on a single-track magnetic code object having a uniform bit length is readable by the magnetic field sensors. In the case of a position detection system having the sensor arrangement, the values of magnetic bits are detected in the range of a detected bit sequence and the position of each 0.fwdarw.1 and 1.fwdarw.0 bit transition along a longitudinal axis of a code object is determined from the detected bit values.

This invention provides a position detection apparatus that improves the position detection accuracy. A position detection apparatus includes an absolute track in which when N is an integer of not less than 2, a recording binary sequence created based on a position detection binary sequence in which identical sequences do not exist no matter which N continuous terms are extracted is recorded, and an absolute sensor unit that reads the recording binary sequence from the absolute track, wherein a plurality of terms included in the recording binary sequence consist of two binary values, and when the two binary values are assumed to be 1 and 0, the recording binary sequence is a sequence obtained by replacing one of two values included in the position detection binary sequence with 10 and the other value in the position detection binary sequence with 01.

A method of operating a position encoder apparatus, including a scale having features defining position information and a readhead for reading the scale. The method includes: calculating extrapolated position information from at least one previous reading of the scale; comparing an extrapolated position with a position calculated from a reading of the scale to determine any discrepancy between them; using the extrapolated position information whether or not there is a discrepancy; and maintaining a record of any discrepancies.

A position-measuring device for determining an absolute position includes a measuring scale and a scanning unit that is movable relative to the measuring scale along at least one measuring direction. To generate a scannable signal pattern, the measuring scale has a measuring graduation which includes a raster of stripe elements arranged along the measuring direction at a measuring-scale longitudinal period. For the encoding of an absolute position, the stripe elements have a periodic structure having a measuring-scale transverse period along a transverse direction that is oriented perpendicular to the measuring direction. For scanning the signal pattern, the scanning unit has a two-dimensional detector system having a plurality of detector elements, which includes multiple detector columns having a plurality of detector elements in each case. The detector columns are periodically arranged along the measuring direction and the detector elements are periodically arranged along the transverse direction, so that by scanning the signal pattern, at least three periodic partial incremental signals are able to be generated with regard to relative movements along the measuring direction, as well as at least one absolute-position signal per detector column.

A sensor arrangement for an absolute measuring position detection system based on a magnetic code object has a substantially linear arrangement of magnetic field sensors, wherein a bit pattern encoded on a single-track magnetic code object having a uniform bit length is readable by the magnetic field sensors. In the case of a position detection system having the sensor arrangement, the values of magnetic bits are detected in the range of a detected bit sequence and the position of each 0.fwdarw.1 and 1.fwdarw.0 bit transition along a longitudinal axis of a code object is determined from the detected bit values.

A method of operating a position encoder apparatus, including a scale having features defining position information and a readhead for reading the scale. The method includes: calculating extrapolated position information from at least one previous reading of the scale; comparing an extrapolated position with a position calculated from a reading of the scale to determine any discrepancy between them; using the extrapolated position information whether or not there is a discrepancy; and maintaining a record of any discrepancies.