Abstract: A device for implementing a method for predicting rotational positions of a rotating shaft is disclosed. A motor shaft is rotated over a range of rotation. The device detects each incremental rotation position of the motor shaft from a set of incremental rotational positions being spaced by a fixed increment. Prior to a change in the rotational speed of the motor shaft, the device generates a prediction of each rotational position. When a detected incremental rotation indicates a change in rotational speed of the motor shaft, the device modifies the prediction of each motor shaft position in a continuous manner.

Abstract: A sensor apparatus having a sensor for generating an analog sensor signal with successive minima and maxima is provided. The apparatus can include a first output signal generating device for generating a first alternating output signal in accordance with the zero crossings of the sensor signal; a sequence controller for defining a normal operating phase, in which the first output signal can be output, and a calibration phase, in which a second alternating output signal can be output; and an extremum defining device for the phase-shifted definition of the successive minima and maxima; the sequence controller furthermore having a zero crossing establishing device for establishing fictitious zero crossings of the sensor signal which follow the respective extrema defined by the extremum defining device.

Abstract: An apparatus and method for measuring a characteristic, such as speed, of a machine. A variable reluctance sensor (VRS) is coupled to a resistive element, which filters a portion of a basic output signal generated by the VRS having a frequency above a prescribed threshold level, thus removing high-frequency noise from the basic output signal. An amplifier amplifies the filtered output signal. The filtered, amplified output signal has an increased signal-to-noise ratio such that the machine characteristic, i.e. speed, can be more accurately measured during a slow speed operation. A controller generates a control signal received by a switching device to decouple the resistive element when machine speed exceeds a prescribed threshold level. Then, the basic output signal is used to measure the characteristic of the machine during normal machine operation.

Abstract: The method allows communication with a built-in sensor, in particular a rotational speed sensor, which supplies successive signal pulses as output signal. The sensor is preferably built into a motor vehicle in such a way that it can be supplied with a supply voltage externally via a voltage supply line. The sensor is placed into a detection mode. The supply voltage on the voltage supply line is externally modulated. The modulated supply voltage received in the sensor is analyzed with regard to the fulfillment of a predetermined criterion stored in the rotational speed sensor. And, finally, the received modulated supply voltage is interpreted as an external communication signal if the criterion is fulfilled.

Abstract: A method and system for improving the duty cycle output of a vehicle speed sensor circuit is disclosed. The vehicle speed sensor circuit can be configured, for example as a binary counter, to provide a particular number of pulses per distance of vehicle travel. An output of the vehicle speed sensor circuit is generally divided by placing varying values on particular load pins of an associated counter circuit, thereby providing a substantially improved duty cycle output from the vehicle speed sensor circuit, which is independent of an associated sensor duty cycle. The output of the vehicle speed sensor circuit can be divided utilizing a toggle flip-flop circuit integrated with the vehicle speed sensor circuit. The toggle flip-flop can be configured as an edge-triggered toggle flip-flop. The vehicle speed sensor can be utilized to sense rotating members present in a vehicle. The vehicle speed sensor thus provides a digital pulse output for every tooth that passes in front of the vehicle speed sensor.

Abstract: A high torque/high speed brushless DC motor system for controlling both the speed and torque of the motor including a rotor and a stator, the stator of the motor including a first, second and third winding. The system further includes means for sensing the position of the rotor and means for selectively configuring the first, second and third windings of the stator in a wye connection when the speed of the motor is less than a predetermined value and configuring the windings in a delta connection when the speed of the motor is greater than the predetermined value.

Abstract: The present invention describes a sensor assembly for detecting movements, wherein a sensor signal is produced in an active sensor (1) by an encoder (E) acted upon by the movement, and which includes a first device (2, 3, 4, 5) that permits converting the sensor signal, along with at least one additional information, into an output signal which can be transmitted to an evaluating device, and which is in particular characterized in that a second device (1a) is provided by which a signal voltage that depends on an air slot (d) between the active sensor (1) and the encoder (E) is detected and sent to the first device (2, 3, 4, 5) for transmission as additional information.

Abstract: A method and apparatus for non-contact testing of a rotating shaft includes first and second proximity sensors coupled to an automated shaft testing system. Output signals from the proximity sensors are compared to empirically determined threshold values to determine the presence or absence of a shaft coupling characteristic, the speed of the rotating shaft, and the direction of rotation of the shaft when the shaft is oriented proximally to the sensors.

Abstract: The present invention provides a sensor apparatus having a sensor (2) for generating an analog sensor signal (200) with successive minima and maxima, and a corresponding method for generating an output signal of a sensor apparatus.

Abstract: A device and a method to detect a broken tooth in a pulse signal by measuring one pulse cycle and another pulse cycle, determining whether a ratio of one pulse cycle and another pulse cycle is a multiplied number while wheel speed is constant.

Abstract: The present invention relates to a method for checking or determining the installation air slot between an active sensor and an encoder, wherein the maximum size of the air slot (maximum air slot) which still ensures trouble-free operation of the sensor depends on the level of the supply voltage of the sensor at least within a range of said supply voltage, and which is more particularly characterized by the following method steps: reducing the supply voltage of the sensor to at least one value by which the maximum air slot is each time decreased by a desired test measure, and comparing the at least one test measure with a desired difference between the maximum air slot and the existing air slot by sensing a variation of the sensor output signal by the reduction of the supply voltage, as well as evaluating the comparison result by signaling and/or storing. A corresponding device is also described.

Abstract: In an evaluation circuit for evaluating an output signal of a magnetoresistive sensor (1) for rotational speed measurement, in which the evaluation circuit performs an offset compensation of the sensor signal and comprises a comparator (4) which receives the offset compensated sensor signal and compares it with a reference voltage, a reliable identification of the output signal of the sensor after switching on the arrangement is ensured in that, in an initial mode, the value of the reference voltage is selected in dependence upon the temperature, the temperature dependence being approximated to that of the sensor signal, in that a control unit (6) is provided which, in the initial mode, consecutively checks whether the sensor signal is present, triggers the offset compensation only after the presence of said signal, subsequently checks whether the comparator (4) supplies an output signal, and changes over to a control mode only after the presence of said signal, in which control mode the temperature dependenc

Abstract: A sensor ring and method for forming same is provided in which the ring has a stamped configuration bent into a final configuration. The stamped configuration has a flat, annular sensor portion extending from a cylindrical hub portion and the sensor portion has a plurality of substantially identical, circumferentially spaced window openings therein. Each window opening has an inner edge adjacent to and spaced radially outward from the hub and an outer edge spaced radially inward from the outer peripheral end of the sensor portion and leading and trailing edges extending, respectively, from the ends of the inner and outer edges to form each window as a polygon, preferably a trapezoid. In the final configuration, the sensor portion has a bight segment extending radially outward from the hub and a sensor or finger segment extending from the bight segment in the direction fo the hub to form a U-shaped cross-section.

Abstract: An improved method, for obtaining a datum concerning the rotation speed (n) of a rotating object, such as a motor rotor (32), offers high precision. Typically, the motor has a sensor (61) which supplies a sensor signal that has, for each revolution of the rotor, a plurality A of events such as pulses or pulse edges which are counted by a microprocessor (23) associated with the motor. In order to keep the computation load on the microprocessor from increasing as the rotor speed increases, yet maintain high precision, the measurement is done over a full rotation of the rotor, starts at a first signal event (176), and ends after a third or nth signal event (182) which happens at the same rotational position as the first signal event.

Abstract: The rotation of a rotating magnet is detected by magnetic sensors. The rotational speed is detected from pulse signals detected by magnetic sensors, and the rotational direction is detected from the difference in a shift in phase. Signals different in pulse width are generated according to the rotational direction. A signal selection circuit outputs a pulse signal with timing for the rotational speed. A rotational speed determining circuit outputs a decision signal Sf of a high level when the rotational speed reaches a predetermined speed. When a self-diagnostic circuit determines that the magnetic sensors have malfunctioned, a binary error code generating circuit generates an error signal Sg and a 4-bit error code signal Sh. When the signal Sf of the rotating magnet is brought to a high level, the signal selection circuit outputs an error code signal and allows output an output current Is.

Abstract: A rotation detecting device has the following structure. An intermediate assembly includes terminal pins having projections at given portions thereof; a molded plastic base in which the given portions of the terminal pins are embedded with the projections being exposed to the outside; and a plurality of electronic elements connected to the exposed projections of the given portions of the terminal pins. One of the electronic elements is a sensor element which is mounted on the molded plastic base. A molded plastic housing entirely and hermetically covers the intermediate assembly except a connector part thereof where leading ends of the terminal pins are positioned. For producing the rotation detecting device, two or three molding assemblies are used in order.

Abstract: This wheel speed detector is constructed of a magnetic sensor and a magnetic ring and is integrated with the inside of a seal device. The magnetic ring constitutes a part (core bar) of the seal device. This arrangement can enable the compacting and reduction in the number of components and improve space saving and assembling workability.

Abstract: A position, speed and displacement speed detector for a continuous reference element (2) is described that is constituted by a pair of polar search elements (1A, 1B), comprised of magnetic sheets having longitudinal teeth (10A, 10B) distributed along its face turned to the continuous reference element (2). The polar search elements further comprise a winding (3A, 3B) which, when fed with a pre-established current, generates a magnetic field. The voltage generated in that coil is a function of the permeability measured by the polar search element (1A, 1B) and, accordingly, is a function of the relative position between the teeth of the pair of polar search elements. By reading the coil voltages and through the device for identification of the direction and relative displacement speed of the teeth of the pair of polar search elements and reference element, the position, direction and displacement speed are identified.

Abstract: A device and a method to detect a broken tooth in a pulse signal by measuring one pulse cycle and another pulse cycle, determining whether a ratio of one pulse cycle and another pulse cycle is a multiplied number while wheel speed is constant.

Abstract: A magnetically sensitive sensor for counting pulses for measuring rotational speeds and angular positions of a rotating component via a pulse transmitter connected for rotating with the rotating component automatically adapts its switching points to the respective measurement location conditions. A logic unit initiates automatic adaptation of the switching points from an original state when an operating parameter first exceeds a limit value after the supply voltage of the sensor turned on. The original state is not preset or is coarsely preset. The configuration of the switching points is then stored in a non-volatile data memory specifically for the sensor.

Abstract: An arrangement for sensing the rotational speeds of a wheel or any other rotating member includes a sensor module with a sensor element, a controllable current source with a modulator and a signal conditioning and evaluating circuit. The modulator controls the current source in response to the signals of the sensor element and/or external signals and, as an output signal of the sensor module, delivers a current signal representative of the rotational behavior with status or additional signals superposed on the current signal. The evaluating circuit of the sensor module includes at least two different signal-conditioning networks which, by way of a control network, in dependence on predetermined criteria or conditions, are connected between the sensor element and the modulator controlling the current source and take care of signal conditioning.

Abstract: An electronic trip meter for a bicycle is provided. The electronic trip meter for a bicycle includes a signal generator and a main unit. The signal generator is used for generating a signal each time the bicycle travels over a specific distance, and the main unit is used for receiving the signal, evaluating and displaying the riding data, and generating an alert signal to remind the rider to execute a maintenance operation when the riding distance or the riding time exceeds a preset riding distance or a preset riding time.

Abstract: A GMI sensor for determining spin rate of a rotating body within an external magnetic field is presented. The sensor comprises an oscillator generating an AC drive signal at an oscillator output terminal. A voltage divider circuit includes a first terminal AC coupled to the oscillator output terminal through a coupling capacitor, and a second terminal electrically connected to a reference ground. The voltage divider circuit further includes a GMI fiber having a GMI junction terminal. The fiber is disposed in fixed relation to the rotating body such that impedance of the fiber is modulated by the external magnetic field to provide a modulated drive signal at the GMI junction terminal. A signal processing circuit is electrically connected to the GMI junction terminal to processes the modulated drive signal and provide an output signal indicative of the spin rate of the rotating body.

Abstract: The invention concerns the design methodology for high speed rotating shafts based on the wave spectrum analysis of the vibrational modes of elastic circular rods and shells. In accord with the invention, a shaft is designed by (1) selecting the material of the shaft; (2) determining dilational wave speed of the material as a function of frequency; (3) determining shear wave speed of the material as a function of frequency; (4) solving for critical frequencies of the shaft by solving a three-dimensional characteristic frequency equation for the shaft, the equation being defined by the dilational wave speed, the shear wave speed, and the inner and outer radius of the shell, the critical frequencies defining functions that depend upon physical dimensions of the inner and outer radius; and (5) specifying the inner and outer radius of the shell by minimizing cross-over of critical frequencies over operational rotational speeds of the shaft.

Abstract: A vehicle variable reluctance sensor includes a hollow generally cylindrical sensor housing with an open proximal end. Within the interior of the sensor housing is a coil wound around a “T”-shaped spool. The coil is connected to two electrical terminals by two electrical leads. A channel is formed in the spool between the coil and the electrical leads and the electrical leads are disposed within the channel. The channel is flanked on each side by a lip that extends outwardly from the spool. If the electrical leads become slack under extreme temperatures, the configuration of the channel, in conjunction with the lips, prevents the electrical leads from coming out of the channel and unwinding the coil. As such, it is not necessary to tape the coil or otherwise immerse the coil in varnish to prevent the coil from unwinding.

Abstract: A first portion of a perimeter of an outer circumferential portion of a tire is magnetized with a first polarity along the steel belt in one circumferential direction less than 360° and a second portion of the perimeter is magnetized with a second polarity in an opposite circumferential direction. The magnetic field generated by the magnetized steel belt is detected by two magnetic detection elements, which are set so that the magnetic field detection directions of the two magnetic detection elements are parallel to the side surface of the tire, and the two elements are juxtaposed in a direction perpendicular to the side surface of the tire.

Abstract: A magnetic effect sensor system has a target with a first set of regularly spaced tooth/slot transition target features and a second set of different tooth/slot transition target features interspersed within the regularly spaced features. The mix of target features allows a single magnetic effect sensor to output a clocking pulse train for misfire detection and an encoded pulse train for determining absolute mechanical position by utilizing two thresholds on the sensor output waveform.

Abstract: Apparatus for monitoring fan speeds within a computing system includes a tachometer turning with the fan, providing a tachometer signal including a number of pulses during each revolution of the fan. This tachometer signal is provided as an input to a signal generator in the form of a flip-flop, which generates a square-wave signal having transitions between high and low levels corresponding to tachometer signal pulses. The square-wave signals are provided as inputs to separate input ports of a microprocessor. These input ports are sequentially sampled at a rate providing at least two samples per period of the fastest square-wave signal, so that transitions of each square wave signal during a predetermined time interval can be detected and counted. For each input port, the number of counted transitions is compared to a stored acceptable value to establish whether the fan is operating in an acceptable speed range.

Abstract: An arrangement for determining the rotational behavior of a rotating body or encoder (3) includes a sensor module (1) which comprises a sensor element (2; 2.1 to 2.4), a controllable power source (4) supplying a load-independent current representative of the rotational behavior, a modulator (5) that controls the power source (4) as a function of signals of the sensor element (2; 2.1 to 2.4) and of signals supplied by an external signal source through an additional port (K5), and an evaluating circuit (9). The sensor module (1) is magnetically coupled to the encoder (3). The output signal of the sensor module (1) is a signal, representative of the rotational behavior, with a superimposed status signal and/or additional signal.

Abstract: A method and a sensing device transmit speed information and additional information over a transmission channel. For this purpose, the transmission clock cycle is selected to reflect the speed and is detected by the sensing device. The additional information is transmitted as a modulation of the transmission clock cycle.

Abstract: A system and method for calculating the speed of a moving member having an output device providing an output periodic signal as a function of displacement of the moving member includes measuring a time duration for a plurality of first periodic occurrences of the output periodic signal to occur. A number of second periodic occurrences of the output periodic signal is also counted in a selected time period. A speed of the moving member is calculated as a function of the time duration for the plurality of first periodic occurrences to occur and the number of second periodic occurrences to occur in the selected time period.

Abstract: A magnetization yoke having an exciting coil wound thereon is arranged to hold a magnetic member and a metal ring so that a magnetic flux passes through and magnetizes the magnetic member in the portion held by the magnetization yoke for successively magnetizing the magnetic member along the circumferential direction thereby multipolarly magnetizing the magnetic member in the circumferential direction. Thus, a magnetic encoder having large magnetization strength and a small magnetization pitch error, a wheel bearing employing the same and a method of manufacturing a magnetic encoder can be obtained.

Abstract: There is provided a speed and position signal generator which operates irrespective of mechanical error, and also operates without any delay of signal transmission. The speed and position signal generator generates A, B phase pulse signals corresponding to a frequency set value and direction setting, and outputs these two phase pulse signals and a Z phase pulse signal corresponding to a teeth number set value, and includes a reference clock generator as a reference, a frequency arithmetic operation circuit, a frequency division circuit for frequency dividing an output phase train from the frequency arithmetic operation circuit, an A, B phase generation circuit for generating A, B phase pulse signals using the frequency division signal, and a Z phase generator circuit for generating a Z phase pulse signal.

Abstract: A wheel rotating speed detector for detecting a wheel rotating speed of a motor vehicle, comprising: a magnetism generator provided either at wheel of the motor vehicle or a rotary member integrally rotatable with the wheel; a magnetism detector for detecting magnetism generated by the magnetism generator; a change-over switch enabling the magnetism detector to change over from a normal magnetism detecting mode to a low magnetism detecting mode or vice versa.

Abstract: A fan speed pulse filter is used for a PWM fan. The filter comprises a comparator, a latch circuit and a synchronizer. The fan unit, including a tachometer pulse output, is controlled by a PWM signal for determining the fan speed. By comparing the PWM signal with a reference voltage, the comparator generates a reset signal. The latch circuit, coupled to the comparator and the fan unit, receives the reset signal and the tachometer pulse and outputs a filtered tachometer pulse containing no phantom pulses. Furthermore, a synchronizer generates an output signal without interruption when the PWM signal is switched off.

Abstract: A tire (12) used includes a steel belt in its outer circumferential portion. A magnetic sensor (14) including a pair of magnetic detection elements (18A, 18B), which are arranged so that their magnetic detection directions become parallel to each other or series each other, is set in the vicinity of a rear tire (12) in a trunk room of a vehicle (10). Changes in magnetic field upon revolution of the tire (12) are differentially detected by the magnetic detection elements (18A, 18B), and the revolution of the tire (12) is detected on the basis of the differentially detected output waveform. Among a plurality of peaks present in the differentially detected output waveform, a peak, the potential difference from the immediately preceding peak of which is equal to or larger than a predetermined threshold value, is detected as an effective peak, which is effective for tire revolution detection, and the revolution speed of the tire is calculated by detecting the number of effective peaks.

Abstract: A rotation detector (100) includes a first transmitting element (1) and a second transmitting element (3) each disposed opposite a gear rotor (5) attached to a rotating body as a detected member. A signal processing device (13) is connected to the first transmitting element and the second transmitting element for generating pulse signals based on rotation signals generated by the first transmitting element and the second transmitting element. The rotation detector is characterized in that the signal processing device generates the pulse signals with different pulse widths to distinguish between the case where the first transmitting element generates the rotation signal prior to the first transmitting element and the case where the second transmitting element generates the rotation signal prior to the first transmitting element.

Abstract: A magnetic-field-to-voltage transducer includes a Hall element and a digitally gain-controlled Hall-voltage amplifier that produces an analog voltage Vsig having excursions of one polarity corresponding to the passing of magnetic articles. Vsig is applied to the input of a peak-referenced-threshold signal detector that generates a binary proximity-detector output voltage, Vout, having transitions of one direction upon approaches of gear teeth down to zero speed. A digitally gain-controlled amplifier is connected to the Hall element. A comparator circuit generates a binary signal Vbig (or Vtoobig) that changes from one to another binary level each time that Vsig exceeds a DC target voltage, VTG. The AGC circuit incrementally changes the transducer gain in the direction to bring the peaks in Vsig to just below the target value TTG. Reference voltages VP2 and VN2 are generated that are equal respectively to the most recent peak positive and negative going excursion in Vsig.

Abstract: A tire (12) used includes a steel belt in its outer circumferential portion. A magnetic sensor (14) including a pair of magnetic detection elements (18A, 18B), which are arranged so that their magnetic detection directions become parallel to each other or series each other, is set in the vicinity of a rear tire (12) in a trunk room of a vehicle (10). Changes in magnetic field upon revolution of the tire (12) are differentially detected by the magnetic detection elements (18A, 18B), and the revolution of the tire (12) is detected on the basis of the differentially detected output waveform. Among a plurality of peaks present in the differentially detected output waveform, a peak, the potential difference from the immediately preceding peak of which is equal to or larger than a predetermined threshold value, is detected as an effective peak, which is effective for tire revolution detection, and the revolution speed of the tire is calculated by detecting the number of effective peaks.

Abstract: A sensor is positioned to sense the magnetic field strength of a magnet associated with a rotating body. The sensor produces a signal having a sinusoidal output as the magnet rotates with the rotating body. A controller takes a derivative of the output and calculates the rotational velocity of the rotational body as a function of the derivative.

Abstract: A method is presented for detecting the position and the direction of motion of a movably mounted part on an electric motor that makes provision not only for a single-channel sensor but also a measuring arrangement for the motor current and the rectified motor current by means of which the motor current is activated after operating switching devices to reverse the polarity of the voltage applied to the motor to cause a reversal of the direction of motion. The measuring arrangement establishes from the variation of the motor current over time the point of time of the motor current maximum and transmits this to the evaluation logic. The point of time of the actual reversal of the direction of motion is derived from the point of time of the motor current. Preferably, the current is measured as a reference current value even before falling through the zero crossing.

Abstract: A tachometer has a display responsive to an rpm signal for producing an observable indication of an rpm value. A circuit responsive to an engine input develops a standard rpm signal representative of instantaneous engine rpm, and a differential Power Band amplifier circuit amplifies the difference between the standard rpm signal and an adjustable “offset” rpm signal by predetermined gain to produce an amplified differential rpm signal. A switching circuit selects the standard rpm signal or the amplified differential rpm Power Band signal for driving the display. A peak or valley rpm signal may also be developed and selected for display either in a standard mode or a differentially amplified Power Band mode.

Abstract: A display system for vehicle data provides a smooth and responsive display of vehicle data even when the data is transmitted on an irregular basis by extrapolating from the previously received data when data is not received in a given interval. The invention allows display data to be preempted by higher priority data in a shared communications system.

Abstract: In so-called active sensors which transmit an output signal to an electronic controller, the amplitude of the output signal depending neither on the speed of the encoder nor on the distance between the sensor and the encoder, the problem is that the output signal does not permit identifying whether the air slot size set between the sensor and the encoder is chosen sufficiently small to ensure an appropriate amplitude of the input signal, generated in the sensor, even when dynamic increases in the air slot occur. If the input signal induced by the encoder in the sensor is too low, a sensor-inherent hysteresis threshold is not exceeded, and no output signal is generated. To prevent the sensor from being inadvertently operated at the limits of its maximum permissible air slot, according to the present invention, the sensor-inherent hysteresis threshold is changed over to the higher hysteresis threshold for testing purposes.

Abstract: A magnetic sensing device comprising a magnetic sensor and a digital circuit is disclosed. The magnetic sensor is operable to output an analog signal as an indication of any movement of an object. The digital circuit can include a dynamic reference threshold generator to output a reference signal in response to a detection of a signal feature of the analog signal and to a detection of a diametric signal feature of the analog signal, and an output format generator to output a digital signal in response to a comparison of the analog signal and the reference signal. The digital circuit can include a dynamic reference threshold generator to output a reference signal in response to a detection a first pair of quadrants of the analog signal and a detection of a second pair of quadrants of the analog signal, and an output format generator to output a digital signal in response to a comparison of the analog signal and the reference signal.

Abstract: A rolling bearing unit with rotating speed detector comprises a stationary outer ring member, a rotating inner ring assembly, a rolling elements between the outer ring member and inner ring assembly, a sensor mounted to the outer ring member and a tone wheel mounted to the inner ring assembly and having a cylindrical portion faced to the sensor, such that the portion is formed with an outward facing flange to which a jig can be applied.

Abstract: An evaluation method for an output signal of a sensing device for scanning a cyclic movement, consisting of a rotatable pole wheel provided with equidistant teeth and an inductive sensor, permits recognition and display of damage to the pole wheel, in particular defective or missing teeth. Contrary to known evaluation processes, where error monitoring of the output signal is carried out for a relatively short time period comprising few signal cycles of the output signal, an observation of the output signal is effected for a sufficiently long time span in the evaluation process according to the invention, such that within the time span, at least two complete revolutions of the pole wheel are completed. To detect damage to the pole wheel, the sudden changes in the output signal occurring in the course of a complete revolution are recorded and are compared with changes recorded in previous, complete revolutions.

Abstract: In normal operation, a sensor element emits information only as to whether two or more field-sensitive components are located in peripheral zones of identical or different electromagnetic field strengths of a pulse generator. In order to permit sensor elements of this type determining immediately upon activation of a supply voltage whether an identical electromagnetic field strength on both components corresponds to a zone of low (L) or high (H) field strength, according to the present invention, the sensor element, upon activation of the supply voltage, is initially operated so that the absolute field strength is measured for a given time. If there is a difference circuit between two field-sensitive components (3, 4), the measurement is carried out because one of the components is temporarily switched off, both components are connected in parallel, or both components are connected in series.

Abstract: In the case of a method for checking the width of the measuring air gap of a magnetic speed sensor, square-wave output signals are generated from the measurement signals of the sensor by means of at least one prescribable threshold value. The pulse duty factor of the output signals is held within a prescribed range in the case of an acceptable gap width. In the case of amplitudes of the measurement signal outside prescribed limits, the pulse duty factor deviates in a reliably measurable fashion from the prescribed range. A circuit has the means for carrying out this method.

Abstract: The tachometer includes a microphone for disposition next to the exhaust of the vehicle and an accelerometer for disposition adjacent to its engine. A selected one of the outputs is connected to an ADC which provides digital samples to a central processing unit. Also, the ripple from the battery is sampled and provided to the CPU. The CPU calculates a constant representing the relationship of the frequencies of the ripple samples and the mechanical samples and responds to the ripple samples and the constant to provide output signals corresponding to the speed of the engine. The speed is displayed.