Abstract: A firmware/hardware apparatus for controlling with digital signals the smooth operation of a needle of an electronic analog gauge meter even when the measurand data is provided intermittently.

Abstract: A sensor is connectable with a load circuit via two conductors. The sensor receives its electrical power from the load circuit via the two conductors and similarly provides its output signal indicative of the sensed phenomenon via the same conductors. An unregulated source potential is provided to a terminal of the sensor from a supply potential via the load circuit. Voltage regulating circuitry in the sensor converts the unregulated source potential to a regulated operating potential for its active circuit elements. Certain output circuitry in the sensor is connected to the terminal having the unregulated source potential for conveying an output signal from the sensor to the load circuit.

Abstract: A circuit arrangement for generating a useful direct voltage signal associated with the frequency of an alternating current signal serves, in particular, to regulate the synchronism of an electric motor. It includes a comparator circuit (7) which converts the two opposite polarity half-waves of the alternating current signal of a tacho coil (2) into pulses whose edges trigger a measuring and control circuit (18) which generates direct voltages corresponding to the half-period durations of the alternating current signal measured from the respective zero passages.

Abstract: A driving circuit for driving a crossed-coil type instrument used for reading a physical quantity in which a pair of windings surrounding a movable magnet carrying a pointer needle thereon are disposed to cross each other with a predetermined mechanical angle. The driving circuit comprises a digital data conversion circuit supplied with an electrical signal representing the physical quantity to be measured for producing a digital data representing the electrical signal, a pulse data producing circuit supplied with the digital data for producing a number of pulses in correspondence with the digital data, and a drive signal generating circuit supplied with the pulses for generating first and second analog drive signals therefrom. The driving signals are respectively supplied to the first and second windings for moving the magnet disposed in the first and second windings.

Abstract: A position and speed detecting device is provided. This device includes a detection-signal generator comprising a rotor magnet assembly having a plurality of magnetic poles and a coil pattern for signal detection which moves relatively facing magnetized bodies of the rotor magnet assembly, a speed-signal detector for taking out a signal for frequency detection from said coil pattern for frequency-signal detection to produce a signal for speed detection; and a position-signal detector for producing a signal for position detection from said coil pattern for position-signal detection.

Abstract: In the embodiments described in the specification, a device having gear teeth to provide magnetic asymmetries rotates adjacent to a permanent magnet which is part of a mechanical mounting for a piezoelectric transducer. Relative motion between the gear teeth and the magnet subjects the transducer to a varying mechanical stress so that it generates a pulsed output voltage signal having an amplitude which is independent of surrounding influences.

Abstract: A magnetic sensor bearing utilizes an adaptive threshold circuit for signal processing in order to compensate for external factors such as temperature, stress, aging, and external magnetic fields which all affect a fixed reference signal used with a comparator. As the magnetic sensor's output signal drifts due to these external factors, the adaptive threshold circuit causes the reference signals to drift in a complementary manner so that the magnetic sensor bearing continues to function properly in spite of the external factors.

Abstract: The circuit comprises a comparator 1 fed by a quasi-sinusoidal signal delivered by a source 2 for converting the positive alternations of the signal into pulses acceptable by digital computing means. According to the invention, the circuit comprises a current source 7 selectively connectible to the circuit in order to vary its sensitivity and to thus enable an evaluation of the amplitude of the signal delivered by the source 2. Application to the diagnosis of the operating state of a variable reluctance sensor delivering a quasi-sinusoidal signal representing the speed of rotation of a shaft fitted in a motor vehicle.

Abstract: Known rotational signal generators for generating signals that correspond to the rotational speed and/or the angle of rotation of a rotatable component part may be connected with the rotatable component part, by means of a coupling or the like. This coupling results in higher space requirements and in an expensive assembly of the rotational signal generator. The rotational signal generator according to the invention is equipped with a hollow shaft and can be fitted onto the rotatable component part. For the compensation of misalignments or the like of the rotatable component part, the rotational signal generator is mounted elastically. The rotational signal generator may be used for measuring the rotational speed, for measuring the angle of rotation, for measuring the length and for similar operations in the fields of driving technology, systems construction, automatization technology and the like.

Abstract: A speed detector, for use with a tone wheel having metal teeth, employs two coils positioned in offset relation near the tone wheel for interacting with the tone wheel teeth and thus changing their respective inductances. One coil is in a phase sense oscillator circuit and the other is in a tuned sensor network. The oscillator is coupled to, and drives, the tuned network. The change in coil inductances effects a shifting of the phase of the output signal from the oscillator relative to the output signal from the tuned network. The phase sequence of those two output signals also reverses itself cyclically as the tone wheel rotates, and a phase reversal detector detects that reversal and uses the event to provide timing reference pulses for a final determination of speed.

Abstract: An ignition monitoring circuit for an ignition system of an internal combustion engine of an automobile, which comprises, in addition to a pulse height and a pulse width shaper circuit, a circuit for eliminating an initial erroneous pulse which is generated from the pulse width shaper circuit upon making of the key switch. The pulse height shaper circuit shapes impulses corresponding to an ignition voltage into pulses of predetermined height; the pulse width shaper circuit shapes the output pulses of the pulse height shaper circuit into pulses of predetermined width. The eliminating circuit comprises: a serial circuit of a resistor, a diode, and a capacitor, coupled across the battery; and a transistor, having its base coupled to the output terminal of the pulse height shaper circuit through an inverter, which is coupled in parallel with the serial connection of the diode and the capacitor.

Abstract: In an apparatus for detecting a rotating speed of a rotating object, in which a pulse train having a frequency proportional to the rotating speed is generated and the rotating speed is detected by detecting the period of the pulse train, the period detection results are over-sampled to form a recursive filter having a peak at the frequency where the frequency characteristic of the period detecting operation becomes zero. As a result, the frequency characteristic of the apparatus as a whole does not have a peak. The phase delay due to the period detecting operation is reduced.

Abstract: An instrument with cross-coil type movable magnet which performs desired indication by A-D converting in accordance with the state of an object under measurement and applying to the crossed coils the current corresponding to a digital value after A-D conversion, comprising an A-D converter to which an input signal corresponding to the state of the object under measurement is sent after overlapping with a dithering ripple, thereby enabling improvement in the resolution of pointer indication.

Abstract: A system and method determines the rotational speed of a rotating member by determining speed from signals having a frequency directly proportional to the rotational speed. The system provides for the estimation of rotational speed even if no speed signals are detected over a sampling interval.

Abstract: An apparatus for electrically detecting the speed of a vehicle or the rotating speed of a wheel which is especially suitable for accurate speed detection in an anti-skid control circuit. This apparatus includes a rotor fixed on a rotating portion of the vehicle and provided with protruding timing teeth on the peripheral surface thereof at regular intervals and a sensor provided in the vicinity of the teeth of the rotor and not being in contact with the teeth of the rotor. The sensor detects the movement of the teeth with the rotation of the rotor electro-magnetically or by high frequency and outputs an electrical pulse signal as a speed detecting signal. In order to obtain accurate speed from the pulse signal, the center position of the pulse signal is obtained from both the output timing of the front or rear edge of the pulse and the pulse width, and the rotating speed of the rotor is calculated on the basis of the center position.

Abstract: The data display instrument for a bicycle comprises an LCD field having an analog scale field to display the momentary travelling speed and an analog scale field to display the pedalling speed. The scale fields are automatically switchable to two measuring ranges. Furthermore, two digital numerical fields are provided in which a multiplicity of information concerning the riding situation can be displayed in dependence on the travelling speed. In addition to the momentary speed and the momentary pedalling speed which are displayed in the scale fields, the digital fields will during travel display the distance travelled since a last reset and the average speed. Immediately after the bicycle comes to a standstill, the digital fields will indicate the travelling time since the last reset and the maximum speed. After a predetermined period of time has elapsed during which the bicycle continues to remain immobile, the digital fields will indicate the total distance travelled and the wheel diameter.

Abstract: A device for detecting the rotational speed of a motor by a first rotational speed sensor and at least a second rotational speed sensor and a switch unit connected to the rotational speed sensors, the switch unit selecting signals from one of the sensors within a respective given rotational speed range.

Abstract: A movement parameter sensor for sensing of parameters of movement between a stator member defining a frame of reference and a rotor member movable relative to the stationary member about a rotation axis. The sensor includes field providing means for generating an electric field located at the stator member, the field providing means including a pole arrangement comprising an array of four source electrode means arranged adjacent to each other along a field line around the rotation axis. The field providing means includes an excitation signal generator for generating four equal frequency excitation signals at 90 degree increments of phase, each one of the four excitation signals being applied to a respective one of the four source electrode means such that a virtually moving electric field is created at the source electrode means so that the electric field effectively moves relative to the stator member along the field line.

Abstract: In a speed detecting apparatus for detecting the rotational speed of a rotating body mechanically coupled thereto, an encoder generates one cycle of a sine-wave signal each time its angular position of rotation changes by a predetermined unit amount. A zero-crossing pulse is generated at each zero-crossing point of the sine-wave signal generated from the encoder, and the phase angle of the sine-wave signal is detected on the basis of the zero-crossing point of the sine-wave signal generated from the encoder. In a high speed range, the rotational speed is detected on the basis of the ratio between the number of zero-crossing pulses and the time interval between a first one and a last one of the plural zero-crossing pulses. On the other hand, in a low speed range, the rotational speed is detected on the basis of the combination of the number of the zero-crossing pulses appearing within a predetermined period of time and the phase angle of the sine-wave signal.

Abstract: A method is presented in which at least one of the sinusoidal voltages (U.sub.S) which is induced in the stator windings by the residual magnetism or remanence of the rotor in a rotating-field machine, the frequency of which corresponds to the rotor speed is converted into a symmetrical square wave signal, (U.sub.R), the frequency and the phase of this square wave signal (U.sub.R) matching with the frequency and the phase of the induced sinusoidal voltage (U.sub.S). From this square wave signal (U.sub.R), an output signal (U.sub.DA) proportional to the frequency thereof is generated. Thus, a method is obtained by which the time required for finding the operational speed of the rotating-field machine (2) is reduced considerably so that a frequency converter can be connected to the rotating-field machine (2) rapidly at a synchronous speed.

Abstract: The device includes a comparator (4) fed by a quasi-sinusoidal signal (3) delivered by a variable reluctance sensor, for converting alternations of the signal into pulses acceptable by digital computing means. According to the invention, the device includes a selectively connectable feedback resistor (R5) for varying the threshold of the comparator in such a way as to check, at a given frequency of the signal, the correctness of the amplitude of the signal (3) provided by the sensor. The device may be used for the checking of the operational state of a variable reluctance sensor delivering a signal indicating the speed of rotation of a shaft fitted in a motor vehicle.

Abstract: To the primary winding of a synchronous electric machine, a polyphase a.c. excitation signal from an excitation circuit is applied. Thus, an induced voltage signal, the phase of which varies by an angle proportional to a rotational position of a rotary body, is produced on the secondary winding of the synchro. A phase difference produced between the a.c. excitation signal and the induced voltage signal is detected by a phase difference detecting circuit. This phase difference detecting circuit detects not only a phase difference itself, but also detects the time at which the phase difference has been detected. On the basis of the phase difference and the time thus detected, a predictive computation circuit predicts a rotational position of the rotary body at an arbitrary time.

Abstract: A magnetoresistive sensor monitors the passing of teeth on a rotating wheel and generates a DC biased speed signal. An amplifier compares this voltage with the capacitor voltage and charges or discharges the capacitor through a pair of parallel coupled, oppositely poled diodes to maintain the capacitor voltage equal to the DC biased speed signal. The voltage across the diode pair is supplied to a comparator switch to provide a pulse train having a frequency that is a measure of the rotational speed of the wheel.

Abstract: An electronic instrument is mounted on a handlebar of a bicycle. An instrument carrier is fastened to the handlebar. The instrument itself is engageable with the instrument carrier for holding engagement. A signal receiver is fastened to one leg of a fork which carries a bicycle wheel. The receiver is opposite the bicycle wheel. A signal inducer is mounted on a spoke of the bicycle wheel. The signal inducer generates signals within the signal receiver. These signals are supplied from the signal receiver by a cable to the instrument carrier. The instrument carrier is provided with contacts. Complementary contacts are provided on the instrument. When the instrument is engaged with the instrument carrier the electrical contacts of the instrument carrier and of the instrument come in mutual electrical engagement. At least one of the contacts is provided on a silicon rubber block which is elastically deformable when the contacts of the instrument carrier and the instrument are brought in electric connection.

Abstract: A signal detector for a cycle computer comprises a head, a sensor supported by the head, and a flexible strap having one end connected to the head. The head includes a housing having a curved abutment surface shaped to bear against the curved abutment surface of a support tube such as a leg of a bicycle fork or a rear stay tube. The head has a strap-guiding surface defining one wall of a strap-receiving passageway extending completely through the housing and tangent to the curved abutment surface. The passageway has a strap entrance portion adjacent the curved abutment surface and a strap exit portion remote from it. The strap has transverse teeth along the inside surface facing inwardly into the passageway when the strap extends through it. In the embodiment disclosed, the head is molded of plastics material and includes an integral pawl in the passageway.

Abstract: This invention is directed to a combination touchless (photo type) and contact type tachometer having a digital display for measuring high, medium and low rotating and surface speeds. Mechanical rotation may be detected by a photo emitting-receiving sensor on the left-hand end of the device or by the contact transmitter located on the right-hand side. The received signal is amplified by an amplifier circuit and regulated by a regulator circuit. Subsequently the data is processed by a standard micro-processor IC circuit, for performing calculations, unit conversion and display decoding. The speed and other information are precisely displayed by a shiftable and reversible, rotatable 180.degree., digital displaying unit to achieve the advantages of an easy to read, precise, economical and effective tachometer.

Abstract: A rotation sensor for vehicle includes a drive shaft connected to a rotation shaft of a vehicle by a transmission member, a ring-shaped magnet member provided onto the drive shaft and a detector for detecting change of magnetic flux caused by rotations of the magnetic member, wherein rotation frequency or rotation speed can be measured by detecting the changes of the magnetic flux. The magnetic member is formed of a composition of heat resisting resin and magnetic materials, and the formed magnetic member is fixed to the drive shaft through a heat resistant elastic member. As a result, even if the rotation sensor is located in high temperature place, e.g. around an engine, there is no possibility that a crack in the magnet member will be caused since expansion or contraction in the magnetic member can be absorbed by the elastic member.

Abstract: An electronic interface device is provided for use between a sensor and a display unit, including a controllable generator which delivers a signal to the display unit and is connected to an input of a comparator whose other input receives the output signal of the sensor. The output of the comparator controls the up counting or the down counting of an up-down counter of clock pulses. The sign output of the up-down counter controls the generator.

Abstract: A signal whose frequency is proportional to a rotational speed of a rotor and whose rising and falling angles near points crossing zero becomes larger with the rotational speed of the rotor is used to produce a first signal of amplitude corresponding to the rising and falling angles and a second signal of amplitude corresponding to the frequency, a difference between the first and second signals is evaluated, and the first or second signals are corrected with the difference.

Abstract: A method for monitoring of a tachometer signal is suggested, wherein the tachometer output signal is not only monitored with respect to its presence, but in addition also with respect to its plausibility. One exemplified embodiment may be realized with the assistance of a correspondingly programmed computer, wherein the tachometer signal change is checked to determine whether it is within predetermined limits. Furthermore, a possibility of reciprocating switching between erroneous and non-erroneous speed signals is eliminated.

Abstract: Apparatus for measuring velocity utilizes quadrature input signals provided by a transducer and divides the derivative of one of the signals by the magnitude of the other to obtain a measure of velocity. The apparatus may be digital or analog. It is particularly suitable for the measurement of velocity where the quadrature signals are provided by an optical grating and transducer arrangement.

Abstract: A system and method for determining the rotational speed of a rotating member is described that determines speed from signals having a frequency directly proportional to the rotational speed. The speed signals are counted during each of successive sampling intervals. At the end of each sampling interval, the rotational speed is determined based on a calculation interval that is the time interval from the next-to-last speed signal generated in the prior sampling interval to the last speed signal generated and the number of speed signals occurring in the calculation interval. The resulting overlapping calculation intervals minimize the influence of one speed signal on successive determinations of rotational speed.

Abstract: An apparatus for detecting the rotation speed of a rotatory member such as a rotary shaft of an electric motor comprises a first counter for counting the pulses of a pulse signal of a frequency proportional to the rotation speed of the rotatory member, a presettable down-counter for counting down a predetermined value sequentially in response to clock pulses, and a CPU for reading out the count value of the first counter upon completion of prescribed count-down of the presettable down-counter and computing the rotation speed of the rotatory member on the basis of the count value thus read out. And upon termination of such computation, the CPU changes the count value of the presettable down-counter back to the predetermined value.

Abstract: A device for the production of a tachometry signal of infinite resolution and without ripple from an inductive position sensor. The sensor is fed by a sinusoidal reference signal and supplies two phase signals. A resistance-capacitance circuit tuned to the frequency of the reference signal is fed by the two phase signals of the sensor and supplies a sinusoidal signal whose phase angle is proportional to the rotation of the sensor. This signal is then digitized and processed by digital phase comparators and low-pass filters before differentiation. This includes the use of particular digital phase comparators, each associated with a particular return to zero detector, to produce by a storage flip-flop and an electronic switch, the outgoing tachometry signal with the aid of a single differentiator with a device for elimination of discontinuities.

Abstract: A speed control system comprises a speed control unit and a test unit. The control unit has a Hall effect transducer for producing a signal representative of vehicle speed and a comparator for comparing that signal with a voltage reference source from which a control signal may be produced to control the vehicle throttle in the event of a disparity so as to maintain vehicle speed at a preset limit. The test unit is employed to set the voltage reference source.

Abstract: A firmware/hardware electronic digital speedometer connected to a vehicle multi-measurand data communications system maintains virtually no flicker in the display of digital numbers in a digital display unit such as a vacuum fluorescent display during movement of a vehicle when no change in speed is apparent. A speed sensor supplies speed information to a first computing unit which establishes an accumulated count of speed during a first interval. Then the first computing unit supplies over a communications link the speed count to a second computing unit at a rate that approximates the update rate of the display unit. The second computing unit processes the speed data in a particular manner to effect the virtually flicker-free updating of the display and improved accuracy.

Abstract: A digital tachometer for an internal combustion engine includes a circuit for receiving a pick-up pulse having a frequency related to the rotation speed of the engine and outputting a wave shaped pick-up pulse. This circuit filters the pick-up pulses and regulates the filtered voltage to provide a d.c. output for powering the tachometer. A crystal controlled oscillator and divider provides update pulses at intervals of 1 to 10 seconds and provides sampling pulses at frequencies of 1 to 5 kilohertz. A display counter and driver counts speed pulses indicative of speed between update pulses and latches the count until the next update pulse. A numerical display displays the count currently latched in the display counter. A multiplier/divider recieves the pick-up pulses and divides them by the number of pulses per revolution to provide pulses indicative of the engine rotational speed.

Abstract: In a timing signal generating apparatus for generating a timing signal showing that a rotating member has reached a target rotational angle position, the apparatus comprises a first generator for generating scale pulses every time the rotating member rotates N degrees, a second generator for generating a reference pulse used for discriminating a prescribed scale pulse from other scale pulses, and a calculator for performing a calculation in which a target rotational angle position of the rotating member is the dividend and N is the divisor and outputs first and second calculation data representing the quotient A and the remainder B respectively. The apparatus is responsive to the reference pulse, the scale pulses and the result of the first calculator and produces a first timing pulse indicating the timing when the rotating member has assumed a rotational angle position indicated by N.times.

Abstract: A programmable cycle meter assembly (17,117) for monitoring a cycling member by receiving an input signal from a transducer (13,113) proportional to the cycles of the monitored member and for indicating various cycle rates by a speedometer or tachometer (36) in linear proportion to a linear array of corresponding frequencies. The assembly includes a circuit (17, 117) which is characterized by a switchable filter means (12,112) which filters out unwanted frequencies above a predetermined frequency of the input signal from the transducer (13,113). a switchable divider (20,120) is used for adjustably dividing the input signal for changing the proportion of the frequency by variable a predetermined ratio to produce a repetitive rate (24,124). A fixed frequency to voltage converter (28,128) converts the repetitive rate adjusted frequency signal (24,124) into a proportional voltage for indicating cycle rate on a meter (36) for various configurations of the cycling member.

Abstract: A rally-oriented meter device for motorcycles, includes a meter unit, a fixing assembly for fixing the meter unit in the vicinity of a handle bar of the motorcycle, and a sensor for detecting the number of revolutions of a front wheel of the motorcycle. The meter unit has an internal electric circuit, a display section, and an operational section. The internal electric circuit comprises an integration circuitry for an integration of a travel distance of the motor cycle. A correction circuitry provides the integration circuitry with a correction signal representing a correlation factor. The operational section comprises a calibration switch system for providing a control signal for commanding the correction circuitry to start and stop an action thereof to determine the correction factor. The display section comprises a first display element for displaying the travel distance in a predetermined unit, and a second display element for displaying the travel distance in a unit smaller than the predetermined unit.

Abstract: A vehicle tachometer kit including a pick up coil that is adapted to be mounted on the outside of the vehicle's alternator to sense its rotating field without any disassembly. An induced signal in the coil from alternator field leakage provides the normal input to a user calibrated r.p.m. display driving circuit in the tachometer that can be calibrated for different alternators and drive pulley ratios without another tachometer by selectively applying a simulated input reference signal to the display driving circuit and adjusting the r.p.m. display until a scheduled ratio is achieved between the displayed r.p.m. and the reference signal.

Abstract: A motion measurement device, more particularly designed for measurement of a rotation of a body around an axis. This device comprises a coded wheel drivably connected to said body for rotation and comprising a plurality of holes regularly distributed around said axis. Said holes are binary digits and for one digit is constituted by a simple hole passing through the wheel and, for the other, an open hole connected to the nearest edge of said wheel by a narrow slit. A sensor placed on the path of the holes and comprising two coils facing one another allows determination of the distance travelled by the moving body connected to said coded wheel. The speed and acceleration of the moving body can also be determined.

Abstract: A speed detection apparatus for detecting speed of electric equipment on the basis of a sampling interval so as to stably operate a variable speed control system connected thereto.The sampling interval is varied in accordance with an input current to be supplied to the electric equipment to compensate for different current pulsations due to different modes of operation and the torques produced at different load conditions.

Abstract: A tachometer circuit is described that has a zero ripple d-c output that is directly proportional to the frequency. The circuit includes a pair of full wave rectifiers to act upon the sine and cosine signal inputs. The rectified currents are first squared, then summed together and finally the square root is taken. Since the quantity .sqroot.sine.sup.2 +cosine.sup.2 is a constant, there is no ripple and no output filtering is required to eliminate ripple. This means that the output can follow very rapid changes in frequency and no lag is introduced by the inclusion of low pass signal filtering.

Abstract: Vehicle speed values are preliminarily stored in an apparatus including a pulse generator 2 coupled to a speed sensor 1, a microprocessor 4 and an electronic memory 14, and a visual speed reconstruction is provided by reading out data from the memory 14 to an external recording instrument 32. The pulses generated with separations corresponding to a given road length act as interrupt signals for a counting operation performed in the microprocessor 4 so that the count or a speed value derived therefrom is transferred for each interrupt signal to the memory 14. The memory has a number of series-arranged memory blocks 15-18 having cyclically addressed memory locations arranged as circular lists and divided into sections having an equal number of memory locations, with a marking of the first memory location in each section.

Abstract: A process for determining a speed and a device for implementing same are provided, wherein the counting device comprises a microprocessor, a programmable counting circuit comprising three counters and connected to the address/data bus of the microprocessor, a storage flip-flop circuit storing the selection addresses of the counters, each counter being associated with a register for preselection of a value for reinitialization of the counters and a common register of the counted values. A logic circuit receiving a masking signal produced by the third counter transfers, to the INTO input of the microprocessor, interruption signals.

Abstract: A displacement sensor is provided with first and second piezoelectric elements, a pair of electrodes at one and the other ends of each of the first and the second piezoelectric elements; a permanent magnet mechanically fixed to one end of the first piezoelectric element; a small piece mechanically fixed to one end of the second piezoelectric element and having almost the same weight as that of the permanent magnet; and a base plate to which the other ends of the first and the second piezoelectric elements are mechanically fixed; wherein the electrodes provided at the other end of each of the first and the second piezoelectric elements are electrically connected, and the electrodes provided at one end of each of the first and the second piezoelectric elements are used as output terminals.Also, a pair of small pieces made of a magnetic material and a non-magnetic material can be used instead of the above permanent magnet and small piece.

Abstract: A pulse signal is generated by a wheel speed sensor with a frequency proportional to the speed of rotation of a vehicle wheel, the pulse signal comprising a plurality of frames each having a series of a predetermined number of pulses which are tended to be affected by noise and pulse mutilation. Pulses in each frame are counted and from the count is derived an instantaneous wheel speed value. The difference between the successively derived instantaneous speed values is taken and compared with a predetermined threshold. A first or a second indication is given in response to the difference being lower or higher than the threshold, respectively. If the first indication is given, output signals representing the average wheel speed and average wheel acceleration of the wheel are derived from the instantaneous speed values of successive frames.

Abstract: An anti-skid control system includes a wheel speed calculation in which newly derived wheel speed is compared with a wheel speed derived at an immediately preceding calculation. When the newly derived instant wheel speed is different from the previously derived old wheel speed beyond a predetermined value which is variable in dependent upon variation of the wheel speed derived at the immediately preceding calculation. A back-up signal is derived and output as a replacement of wheel speed data. The back-up signal may have a value substantially corresponding to a wheel speed data avoiding error component in the instant wheel speed.

Abstract: The present invention relates to a running speed detector comprising:a pulse encoder which generates pulses of a frequency proportional to the running speed of a rotary member;pulse period counting device for counting the periods of pulses having said frequency relying upon clock signals;memory for storing ounted values of periods counted by said pulse period counting means; andand a calculating device which receives pulses having said frequency, which calculates the sum of n latest counted values that have been counted already after the arrival of each of said pulses or after the arrival of a predetermined number of pulses, and which calculates the running speed that varies in proportion to a ratio of the number n of counted values of periods to said sum of counted values of periods.