A circuit includes a bandpass filter and a self-tracking circuit. The bandpass filter has a first input node configured to receive an input square wave signal and an output node configured to provide an output sine wave signal. The bandpass filter includes a first binary-weighted programmable resistor array. The self-tracking circuit includes a second input node coupled to the output node. The self-tracking circuit includes a counter, and the counter includes an output node coupled to the first binary weighted programmable resistor array.

An electromagnetic induction type encoder, wherein a detection head has a drive coil generating magnetic flux, wherein a scale has a plurality of connection coils arrayed in a fundamental period in a measurement axis direction, are electromagnetically coupled with the magnetic flux generated by the drive coil and generates magnetic flux fluctuating in a predetermined spatial period in the measurement axis direction, wherein the detection head has a plurality of receiver coils arrayed in the fundamental period in the measurement axis direction and are electromagnetically coupled with the magnetic flux generated by the plurality of connection coils and detects a phase of the magnetic flux, wherein /22d<L</2 is satisfied when a distance between line width centers of the plurality of connection coils is L and a line width of the plurality of connection coils is d.

A circuit includes a bandpass filter and a self-tracking circuit. The bandpass filter has a first input node configured to receive an input square wave signal and an output node configured to provide an output sine wave signal. The bandpass filter includes a first binary-weighted programmable resistor array. The self-tracking circuit includes a second input node coupled to the output node. The self-tracking circuit includes a counter, and the counter includes an output node coupled to the first binary weighted programmable resistor array.

Provided is an electromagnetic induction type displacement detection apparatus in which influence of a change in magnetic flux received by a receiving device can be suppressed. An electromagnetic induction type displacement detection apparatus 1 includes a scale including a scale coil and a head 3 relatively moving with respect to the scale. The head 3 includes a transmitting device 4 that generates magnetic flux in the scale coil, and a receiving device 5 that includes a first receiving unit 51 and a second receiving unit 52 each receiving the change in the magnetic flux and in which the first receiving unit 51 and the second receiving unit 52 are arranged to be shifted from each other along a measurement direction. The receiving device 5 includes one end portion 10a and another end portion 10b in which a density of a plurality of receiving coils 500 is made sparse, and a central portion 11 that is positioned between the one end portion 10a and the other end portion 10b and in which the density of the plurality of receiving coils 500 is made dense. The electromagnetic induction type displacement detection apparatus 1 includes the one end portion 10a and the other end portion 10b and the central portion 11, whereby influence of the change in the magnetic flux received by the receiving device 5 can be suppressed.

Provided is an encoder that can sense an abnormality in the attitude of a detector with respect to a scale. An encoder includes a scale and a detector, the scale being provided on one measurement target part with marks arranged on the scale, and the detector being provided on another measurement target part and configured to detect an amount of relative movement with the scale. The scale includes a sensing unit that senses the attitude of the detector with respect to the scale, and thus even in a case where an abnormality in the attitude of the detector with respect to the scale cannot be sensed on the basis of a change in a signal read by a reading unit, the abnormality can nevertheless be sensed.

A sensing circuit in a device having a moving body in which a unit to be detected including first and second pattern units spaced apart from each other is formed includes an oscillation circuit unit including first and second oscillation circuits fixedly mounted on a substrate spaced apart from the unit to be detected, including, respectively, first and second sensing coils having first and second inductance values depending on areas of overlap between the first and second sensing coils and the first and second pattern units and outputting, respectively, first and second sensed oscillation signals based on the first and second inductance values; and a sensing circuit outputting an output signal having movement information of the moving body based on each period count value for each of the first and second sensed oscillation signals using a reference oscillation signal.

An electromagnetic induction type encoder, wherein a detection head has a transmitter coil configured to generate magnetic flux, wherein a scale has a plurality of connection coils arrayed in a measurement axis direction, are configured to be electromagnetically coupled with magnetic flux generated by the transmitter coil and generate magnetic flux that fluctuates in a predetermined spatial period in the measurement axis direction, wherein the detection head has a receiver coil having a plurality of coils arrayed in the measurement axis direction on a predetermined face of the detection head and are configured to be electromagnetically coupled with the magnetic flux generated by the plurality of connection coils and detect a phase of the magnetic flux, wherein a current direction of one of the plurality of coils is opposite to a current direction of another coil of the plurality of coils next to each other.

Provided is an encoder device capable of reducing interference between a magnetic field generated in a reference mark and a magnetic field generated in a scale. An encoder device is provided with a reference mark and a head. The reference mark has: a first scale coil; and a second scale coil electrically connected to the first scale coil. The head has: a transmission coil that transmits an electromagnetic wave without any contact to the first scale coil; a reception coil that receives an electromagnetic wave without any contact from the second scale coil; and electric circuits that generate a pulse for generating an origin signal from the electromagnetic wave received by the reception coil, if the transmission coil faces the first scale coil and the reception coil faces the second scale coil.

Devices, systems, and method for detecting, determining and compensating for offset error arising in inductive position and torque sensors are described. In accordance with at least one embodiment, an offset coil can be configured for use within an inductive sensor and include a first trace and at least one second trace. The first trace and the at least one second trace may be drawn within a stator of an inductive sensor. The first trace and the at least one second trace may be drawn within the stator proximate to a pair of excitation coil connecting leads, drawn on a first plane within the stator, and on at least one plane substantially parallel to the first plane such that wherein an excitation coil flowing through the pair of excitation coil connecting leads induces an offset coil signal in the first trace and at least second trace.

The electromagnetic induction type position detector includes a scale having a plurality of gradation coils, a head having a transmission unit and a reception unit, and a control unit. Each of the plurality of graduation coils includes a transmission graduation arranged with a pitch L1, a reception graduation arranged with a pitch L0 different from the pitch L1, and a connection unit. The transmission unit includes three transmission coil groups that are constituted by pluralities of transmission coils, each being arranged with a pitch L1, and that are arranged such that adjacent transmission coil groups have a phase difference. The reception unit includes three reception coil groups that are constituted by pluralities of reception coils, each being arranged with a pitch L0, and that are arranged such that adjacent reception coil groups have a phase difference identical to the phase difference of the three transmission coil groups.