An angular position sensor system includes a two-pole magnet rotatable about a rotation axis; a magnetic sensor device having a plurality of horizontal Hall elements including at least a first, second and third horizontal Hall element located on a virtual circle having a centre located on the rotation axis. The Hall elements are spaced by multiples of 90. The magnetic sensor device has a processing unit connected to the horizontal Hall elements for obtaining a first, second and third signal, and for determining a first pairwise difference between the first and second sensor signal, and for determining a second pairwise difference between the second and third sensor signal, and for determining an angular position of the magnet relative to the sensor device based on a ratio of these pairwise differences.

An angle detector for detecting an amount of angular change due to the rotation of a rotary body. The angle detector is provided with a rotary body rotating around a rotation axis, a graduated scale having a plurality of graduations along the circumference of the rotary body in a rotation direction, and a plurality of sensors disposed along the circumference. Each of the sensors outputs a signal according to an amount of angular change on the basis of the plurality of graduations. The output signal includes a fundamental wave component having one of the plurality of graduations as a first period first order, and a harmonic wave component having an order that is an integer multiple of at least two times the fundamental wave component. An amount of angular displacement calculated from the output signal includes an angular error component that is due to the harmonic wave component and has an order component that is an integer multiple of the one graduation that is the first period first order. The number of the plurality of sensors is determined on the basis of the number of graduations on the graduated scale and the order component of the angular error component.

A read-out circuit includes an operational amplifier configured to receive input voltage via a positive input terminal; a feedback capacitor connected between an output terminal of the operational amplifier and a negative input terminal of the operational amplifier; a sensor charging/discharging circuit configured to charge or to discharge a sensor capacitor included in a sensor during a first time; and a switching circuit configured to connect the sensor capacitor and the operational amplifier during a second time after the sensor capacitor is charged or discharged.

A position sensor system is arranged for determining a position of a sensor device movable along a predefined path relative to a magnetic source. The system includes the magnetic source and the sensor device. The magnetic source has a first plurality of magnetic pole pairs arranged along a first track and a second plurality of magnetic pole pairs arranged along a second track, centrelines of the tracks are spaced apart by a predefined track distance. The sensor device is configured for measuring at least two orthogonal magnetic field components at a first sensor location, and at least two second orthogonal magnetic field components at a second sensor location. The first and second sensor location are spaced apart by a predefined sensor distance smaller than the predefined track distance, in a direction transverse to the tracks.

A position sensor system is arranged for determining a position of a sensor device movable along a predefined path relative to a magnetic source. The system includes the magnetic source and the sensor device. The magnetic source has a first plurality of magnetic pole pairs arranged along a first track and a second plurality of magnetic pole pairs arranged along a second track, centrelines of the tracks are spaced apart by a predefined track distance. The sensor device is configured for measuring at least two orthogonal magnetic field components at a first sensor location, and at least two second orthogonal magnetic field components at a second sensor location. The first and second sensor location are spaced apart by a predefined sensor distance smaller than the predefined track distance, in a direction transverse to the tracks.

An encoder for detecting rotation information of a first rotation shaft includes a first detector which detects a pattern provided in the first rotation shaft, a first housing case which houses the pattern provided in the first rotation shaft and the first detector, a second housing case which houses at least a part of a shaft portion different from a portion where the pattern is provided, of the first rotation shaft, and an adjusting mechanism which adjusts at least one of an atmospheric pressure and a temperature in the first housing case to be higher than at least one of an atmospheric pressure and a temperature in the second housing case. The inflow of the high-humidity air from a motor into the encoder is prevented or suppressed, so that the condensation in the encoder can be prevented or suppressed.

An angle measuring device includes first and second component groups and a bearing. The first component group includes a scale element having a first graduation. The second component group has a first modular unit, including a position sensor, and a second modular unit, including first, second, and third position transducers, and a compensation coupling. The first and second modular units are connected in a torsionally stiff but axially and radially flexible manner. The angle measuring device is operable in first and second modes. In the first mode, the first graduation is scannable by the position sensor to determine a first angular position. In the second mode, the first graduation or a further graduation situated on the scale element is scannable by the position transducers to determine further angular positions. A corrected relative angular position is determinable based on the first angular position and the further angular positions.

A rotation sensing apparatus includes a detected part, a sensor unit, and a rotation information calculation circuit. The sensor unit includes a first sensor disposed opposite to a first pattern portion, a second sensor disposed opposite to a second pattern portion, a third sensor disposed to be spaced apart from the first sensor in the rotation direction and opposite to the first pattern portion, and a fourth sensor disposed to be spaced apart from the second sensor in the rotation direction and opposite to the second pattern portion. The rotation information calculation circuit is configured to sense the rotation direction, in response to a differential signal, generated based on the first oscillation signal and the second oscillation signal, and an oscillation signal corresponding to maximum and minimum frequencies, from among the first oscillation signal, the second oscillation signal, the third oscillation signal, and the fourth oscillation signal.

A rotation sensing apparatus includes a detected part, a sensor unit, and a rotation information calculation circuit. The sensor unit includes a first sensor disposed opposite to a first pattern portion, a second sensor disposed opposite to a second pattern portion, a third sensor disposed to be spaced apart from the first sensor in the rotation direction and opposite to the first pattern portion, and a fourth sensor disposed to be spaced apart from the second sensor in the rotation direction and opposite to the second pattern portion. The rotation information calculation circuit is configured to sense the rotation direction, in response to a differential signal, generated based on the first oscillation signal and the second oscillation signal, and an oscillation signal corresponding to maximum and minimum frequencies, from among the first oscillation signal, the second oscillation signal, the third oscillation signal, and the fourth oscillation signal.

A position detection device includes a magnetic scale and a magnetic sensor. The magnetic scale includes a plurality of magnets arranged along a first reference direction. The magnetic sensor includes a plurality of detectors that detect a composite magnetic field. The plurality of detectors are each arranged to satisfy AG=N(M−W)/(n−1), where n is the number of magnets of the magnetic scale, M is a distance from a first end to a second end, W is the width of each of the plurality of magnets and is greater than 0 and less than or equal to M/n, AG is a gap between each of the plurality of magnets and each of the plurality of detectors in a second reference direction, and N is a number greater than or equal to 0.4 and less than or equal to 2.