U.S. Philips Corporation

Koninklijke Philips Corporation N.V.

August Petersen

Michael Muth

Volker Graeger

Bernd Seidel

Hans-Ulrich Lochmann

Stephan Linke

Hans-Werner L&uuml;tjens

Arrangement for measuring rotational velocity

An arrangement for measuring a relative linear position between a sensor and a magnetic body, whose position relative to each other can be changed linearly in a predefined direction. The sensor is arranged as a magnetoresistive angle sensor, with little building expenditure and little sensitivity to external influences, and a magnetic strip is provided as the magnetic body, which strip includes a pair of magnetic poles and magnetic field lines running over its length at varying angles, so that the angle of the magnetic field penetrating the magnetoresistive angle sensor depends on the relative position of the magnetoresistive angle sensor to the magnetic strip and the relative position can be computed from the output signal of the magnetoresistive angle sensor.

Arrangement for measuring a relative linear position between an angle sensor and magnetic body

An angle sensor includes a lateral magnetic field sensor element (1) for producing a sensor signal (U.sub.S) which is dependent on the angular position of a target object (6) which is rotatable about an axis of rotation (5). The lateral magnetic field (8) is produced by a magnet (4) which also produces an axial magnetic field (7). Magnetic field sensor elements have a linear characteristic only over an angular range of up to at most 180.degree.. According to the invention, however, in addition to the field sensor element (1) there is also provided a measuring element (2) which determines the direction of an axial magnetic field (7) also produced by magnet (4) and which traverses the measuring element (2). An evaluation circuit (9) is thereby enabled to determine the angular position of the target object (6) from the sensor signal (U.sub.S) produced by the magnetic field sensor element (1) and the direction signal (U.sub.R) produced by the additional measuring element (2), which determination can be performed over an angular range exceeding 180.degree..

Angle sensor having lateral magnetic field sensor element and axial

An angle sensor includes at least two angularly spaced sensor units which measure in a contactless manner and whose sensor voltages are similar but angularly shifted sinusoidal functions (sensor characteristic) of the angle .alpha. to be measured relative to a rotatable element and a processing circuit forms an angle sensor voltage which is a measure of the angle .alpha.. Using limited analog circuitry, a wide angular range is obtained and also a monotonously increasing angle sensor voltage which is dependent as linearly as possible on the angle to be measured, in that the sensor voltages are direct voltages which are constant in time. The processing circuit includes limiter circuits (15) whose input receives the sensor voltages (UMA, UMB), and whose output voltages exhibit values (10, 11) which remain constant when a limit value of the sensor voltages is exceeded, and that the output voltages of the limiter circuits (15) are applied to the input of a summing circuit (16) in order to form the angle sensor voltage.

Angle sensor including angularly spaced sensor units

The invention relates to an arrangement (10) for detecting a moved ferromagnetic element (16) comprising a magnet (11), to which a sensor (14) is assigned on one of its pole faces (12) at a certain distance from the moved element (16). Such arrangements (10) are known, for example, for detecting the speed of a toothed wheel (16). In such known arrangements (10), the positioning of the sensor (14) on the magnet (11) is critical as far as offset voltages in the stationary condition should be avoided in order to obtain a high sensitivity. For an accurate positioning the magnet (11) of such an arrangement (10) has means for producing at least one magnetic imperfection for symmetrization and parallelization of a magnetic field (17) located in the direction of movement (A) of the moved element (16) and of a perpendicular to the pole face (12) for forming a mounting zone (24) free from sensor signal voltage for the sensor (14).

Arrangement with field correcting structure producing a homogeneous

An adaptive revolution-measuring apparatus which includes a magnetic revolution sensor and an apparatus for comparing and evaluating the sensor signal of the revolution sensor to generate a digital output signal (U.sub.A) corresponding thereto, which despite large offset voltage tolerances and shifts uniquely identifies and evaluates the periodic sensor signal. The measuring apparatus contains a window comparator (17) with a controllable window as the apparatus for comparing which via at least one logic switching element (20, 21) drives a flip-flop (25) to produce the output signal (U.sub.A). Further apparatus are provided downstream of the window comparator which continuously generate corresponding reference voltages (U.sub.R1, U.sub.R2) for the window comparator as a function of the raised or lowered values of the sensor signal.

Adaptive measuring apparatus with automatically adjustable window

A phase sensitive output circuit is used at an output of a piezoferroelectric storage element driven by an alternating voltage so that the storage range of the element is practically doubled.

Analog storage circuit including a piezoelectric element

For reducing or preventing unwanted variations at adjacent storage electrodes upon polarization or depolarization of one of the storage electrodes on a PXE body a storage electrode terminating impedance is proposed of a special value.

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Henstedt-Ulzburg, Germany

August Petersen