Methods and apparatus for determining and transmitting speed and/or direction information for a rotating target by a magnetic field sensor. A reference channel signal is generated for a target from at least one magnetic field sensing element and a virtual channel signal in quadrature with the reference channel signal is generated. A tangent signal is generated. A slope of an arctangent of the tangent signal is determined, wherein the slope corresponds to rotational speed of the target. The speed and/or direction of the target can be transmitted by a sensor IC.

An encoder includes scale and detection head. The detection head includes light source (transmitting unit) and light-receiving unit (receiving unit). The light-receiving unit includes light-receiving surface (receiving surface) and converts light received at the light-receiving surface 50 into differential detection signals with two phases and outputs the same. The light-receiving surface includes element array group including four element arrays provided in a parallel manner along an orthogonal direction, with each element array including a plurality of light-receiving elements (receiving elements). The plurality of element arrays in the element array group are disposed at positions where the sum of: (i) a distance in the orthogonal direction from a reference position to a positive phase signal element array; and (ii) a distance in the orthogonal direction from the reference position to the negative phase signal element array, is the same for all the phases of the at least two phases.

Methods and apparatus for determining and transmitting speed and/or direction information for a rotating target by a magnetic field sensor. A reference channel signal is generated for a target from at least one magnetic field sensing element and a virtual channel signal in quadrature with the reference channel signal is generated. A tangent signal is generated. A slope of an arctangent of the tangent signal is determined, wherein the slope corresponds to rotational speed of the target. The speed and/or direction of the target can be transmitted by a sensor IC.

An encoder wheel assembly comprising: a first encoder wheel rotationally fixed to a rotor and having a number n of teeth arranged along the circumference of the encoder wheel; a second encoder wheel rotationally fixed to the first encoder wheel, and having the same number n of teeth as the first encoder wheel along the circumference of the encoder wheel, wherein the teeth of the second encoder wheel have an asymmetrical angular offset relative to the teeth of the first encoder wheel; a first sensor designed to scan the first encoder wheel; a second sensor designed to scan the second encoder wheel; and a controller connected to the first sensor and the second sensor and designed to ascertain the absolute angular position and the rotational direction based on a binary signal derived from a first signal of the first sensor and a second signal of the second sensor.

Disclosed is a method for processing a primary signal produced by a sensor detecting the rotation of a rotating target. The primary signal includes pulses having, for a given speed of rotation of the target, a first positive voltage level for rotation in a first determined direction or a second positive voltage level for the opposite direction. A first secondary signal is generated by comparing the primary signal to a first determined voltage threshold between the first and second voltages. A second secondary signal is generated by comparing the primary signal to a second determined voltage threshold between the second voltage level and zero. A determined delay is introduced in the second secondary signal. A determined time threshold is compared to the duration between an active edge of the second secondary signal and the last preceding active edge of the first secondary signal, indicating direction.

A rotation detection device includes: a detector arranged with a gap to a rotating body in which rotation position information is periodically provided at regular intervals, and detecting a magnetic change as a rotation position of the rotating body; and a signal processor acquiring the rotation position information. The detector has first and second magnetic elements arranged with an interval of a/2 in a rotation direction. Each regular interval is defined as a. The first magnetic element outputs a first signal having a period corresponding to the regular intervals. The second magnetic element outputs a second signal having an opposite phase to the first signal and the period. The signal processor acquires a differential signal between the first and second signals as the rotation position information.

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.

Magnetic field sensor devices, corresponding systems and corresponding methods are discussed where a plurality of magnetic field sensors senses a magnetic field. An evaluation circuit generates a first signal component associated with a periodicity of a magnetic field, and a second signal component at least for periods of the magnetic field exceeding a threshold period length, the second signal component having a resolution smaller than the first signal component.

An apparatus and a method provide an output signal indicative of a speed of rotation and/or a direction of movement of a ferromagnetic object. The sensor includes at least one magnetic field sensing element configured to generate a magnetic field signal in response to a magnetic field associated with an object. The sensor includes a detector configured to generate a detector signal having edges occurring in response to a comparison of the magnetic field signal and the threshold signal. The sensor includes an output circuit configured to generate an output signal having a first format when a characteristic of the magnetic field signal is within a first range and having a second format different than the first format when the characteristic of the magnetic field signal is within a second range, different than the first range.

A touch screen device includes a display screen having a touch surface, an input knob, and a microcontroller programmed to execute a method. The knob has a stationary member with conductive base pads facing the surface and a moveable member. The knob lacks a direct electrical connection to the surface. The microcontroller receives encoder signals as the moveable member moves with respect to the stationary member, with the signals being indicative of discrete touch events between the moveable member and the screen, e.g., via an intervening switch. The microcontroller processes the encoder signals to determine a direction of movement of the knob, and derives a true position of a center point of the knob using a position of each of the base pads. The microcontroller then controls an operation of the touch screen device.