A sensor device has a clock generator, a counter, an exciter device, a sensor element and an evaluation device, and outputs a sensor signal in response to a request signal having alternating leading and trailing edges. The counter reading is incremented differently, depending on whether the request signal has a leading/trailing edge between two successive leading or trailing edges of the clock signal. If the request signal has such a leading/trailing edge the counter corrects the counter reading. The value of the excitation signal outputted by the exciter device depends on the counter reading or a value derived therefrom. The sensor element outputs based on the excitation signal a raw signal, which is supplied to the evaluation device. The evaluation device determines based on this information whether to acquire the raw signal and how to take the raw signal into account when establishing the sensor signal.

Optical encoders and methods of determining rotational movement are provided. The optical encoders include an encoder disk having a patterned signal track comprising a plurality of optically detectable elements disposed on a periphery of the encoder disk, wherein each optically detectable element is associated with a bit in a binary sequence, wherein each bit has a predefined bit depth, a boundary dividing the patterned signal track into at least two sub-regions, wherein each sub-region comprises a subset of the optically detectable elements, at least one sensor arranged to detect an optical signal associated with at least one optically detectable element, and a controller in communication with the at least one sensor, the controller configured to determine an angular position of the encoder disk, wherein the controller determines the angular position based on a detected binary sequence, a detected sub-region, and a look-up-table.

A position-measuring device includes a graduation carrier having a measuring graduation disposed thereon. At least one position sensor is configured to generate position-dependent measurement signals by scanning the measuring graduation. A processor is configured to process the position-dependent measurement signals into position signals. An interface is configured to transmit the position signals to subsequent electronics via at least one data channel. At least one motion sensor is configured to generate time-varying measurement signals. A signal analyzer is configured to analyze the measurement signals in the frequency domain dependent on parameters that are transmittable from the subsequent electronics to the interface unit, and to produce result data that is transmittable from the interface unit to the subsequent electronics.

A rotation angle detection device that is capable of detecting an absolute rotation position with a high accuracy without an error. A rotation detection target rotates together an operatable rotation member and has an outer scale and an inner scale. Two rotation detection elements are arranged at opposite positions across the rotation axis in the radial direction so as to respectively irradiate the outer and the inner scales with light beams and output signals corresponding to reflected components. A control unit calculates a rotation angle of the rotation detection target using the signals. The outer and inner scales are so formed that a signal output from one of the two rotation detection elements increases and the signal output from the other decreases when the rotation member is rotated.

A position detecting apparatus includes a signal detecting unit that detects a plurality of periodic signals, a correction unit configured to correct the plurality of periodic signals using a correction value to generate a plurality of correction signals, a first calculating unit configured to generate a plurality of displacement signals based on the plurality of correction signals and to calculate the position based on the plurality of displacement signals, a second calculating unit configured to calculate a reliability based on the plurality of displacement signals, and a correction value adjusting unit configured to adjust the correction value based on the reliability. The second calculating unit calculates a first reliability corresponding to a first correction value and a second reliability corresponding to a second correction value, and changes the first correction value to the second correction value when the second reliability is higher than the first reliability.

An encoder includes: a phase signal generator that generates and outputs first and second sinusoidal analog signals that are out of phase with each other by 90 degrees, according to a movement of a measurement target; a Lissajous angle calculator that determines a Lissajous angle from the first and second analog signals; and an amplitude adjustor that adjusts an amplitude of only the first analog signal output from the phase signal generator and outputs the adjusted amplitude to the Lissajous angle calculator.

According to an embodiment, an encoder system includes an encoder and an interface. The encoder detects the position and speed of a motor, and generates A-, B- and Z-phase signals. The interface includes an AB waveform recognition circuitry to recognize a waveform of an AB phase, a Z waveform recognition circuitry to recognize a period of an enable state of a Z phase, a starting point storage device to store a value of the AB phase when the Z phase changes and stores an AB-phase change pattern, a starting point recognition circuitry to generate an interrupt signal, and a rotation angle counter to start a new count of the rotation angle of the motor.

A method for automatic calibration of a camshaft sensor for a motor vehicle. The sensor includes a processing module configured to generate, from a raw signal indicative of the variations in a magnetic field which are caused by the rotation of a toothed target and measured by a cell, an output signal indicative of the moments at which the teeth pass past the cell. The calibration method makes it possible, for each tooth, to determine a switching threshold not only as a function of a local minimum and of a local maximum for the tooth during the preceding revolution of the target, but also as a function of a corrective value calculated from a local maximum and/or a local minimum of the raw signal during the passage of a preceding tooth past the cell during a new revolution.

The present invention provides a method for detecting a positional change amount due to a movement of a moving body by reading, with a sensor, a plurality of gradations disposed along the direction of the movement. The method includes: a step for taking, as one period, one gradation among the plurality of gradations and acquiring a pseudo sinusoidal signal in response to the positional change amount; a step for executing a Fourier transform on the pseudo sinusoidal signal within the range of at least one gradation, and calculating, from the spectral intensity of each frequency component obtained by the Fourier transform, the signal intensity of a fundamental wave component and the signal intensity of at least one harmonic component; a step for calculating a gain corresponding to each of the at least one harmonic component by dividing each signal intensity of the at least one harmonic component by the signal intensity of the fundamental wave component; and a step for detecting the positional change amount by subtracting, from the pseudo sinusoidal signal, each harmonic component multiplied by a corresponding gain.

A measurement apparatus includes: a light source that emits light; a scale that has a plurality of tracks whose patterns are different from each other, the tracks passing at least a part of lights emitted by the light source; a light receiving part that has a plurality of light receiving elements that each output an optical signal corresponding to strength of light received through the tracks; and a signal generation part that generates a serial signal in which a plurality of the optical signals are time-division multiplexed and sends the generated serial signal.