Abstract: In an aspect of the invention there is provided a control method for a vehicle travelling on a surface, the vehicle having a vehicle powertrain for generating and delivering power to the vehicle wheels, the method including: measuring one or more parameters associated with motion of the vehicle on the surface; comparing the or each of the measured parameters with a predetermined threshold for said measured parameter that is indicative of a level at which wheel slip of the vehicle may occur; and in circumstances in which one or more of the measured parameters exceeds the predetermined threshold, controlling the torque applied by the powertrain to the vehicle wheels to prevent wheel slip.

Abstract: A gravity sensor (G-sensor) circuit system including a microcontroller that determines whether there is a failure in the G-sensor and, if it is determined that there is a failure in the G-sensor, outputs a failure signal to a controller outside the PCB, or the controller outside the PCB communicates with the G-sensor to determine whether there is a failure in the G-sensor, thus performing the self-diagnosis. The gravity sensor (G-sensor) circuit system performs self-diagnosis, zero-offset, and digital output, thereby using a more accurate sensor signal, improving the vehicle stability, and increasing the control precision and accuracy.

Abstract: The present invention provides a motor drive apparatus which improves a trade-off relation between a stable position detection and noise at its driving. A sensorless drive operation circuit calculates by operation a zero cross point (point p) of a voltage of a position detection phase at the next interval, using time information measured based on an output signal from a comparison circuit at the previous interval and the present interval. After the point p has been calculated, points a and b are detected by interrupting a predetermined time drive current.

Abstract: A method of controlling a vehicle includes determining a desired sideslip angle in the moving road plane, determining an actual sideslip angle in the moving road plane, a desired yaw rate in the moving road plane, and an actual yaw rate in the moving road plane. A controller controls the vehicle system in response to the desired slip angle, the actual sideslip angle, the desired yaw rate and the actual yaw rate in the moving road plane.

Abstract: A method for the control of the drive slip in a vehicle with rear wheel drive, particularly when traveling on difficult terrain or in deep snow, involves independent detection of wheel speeds of both the rear/drive wheels and the front/non-drive wheels. Dynamic values, such as wheel acceleration values, of the front wheels are used as a criterion for increasing the drive slip value of the ASR. The drive slip value of the rear wheels is increased if the difference between the dynamic values, e.g., acceleration values, determined for the front wheels exceeds a threshold value. The increased drive slip value of the drive wheels under the difficult travel conditions results in increased traction as well as increased available engine power.

Abstract: A method and a device for monitoring rotational speed sensors, in particular rotational speed sensors for identifying the wheel speed, are described. A fault is detected if a slip coefficient which is weighted with the time exceeds a threshold value.

Abstract: A technique for estimating a traction characteristic of a surface under a moving vehicle, such as the coefficient of friction of the surface. The traction characteristic can be estimated by generating a torque signal representative of at least an estimate of the amount of torque applied to the driven wheels of the vehicle. A load signal representative of at least an estimate of the load or weight applied to the driven wheels also is generated. The value of the torque signal is divided by the value of the load signal in order to generate a characteristic signal. Depending on the amount of slippage between the driven and non-driven wheels of the vehicle, the characteristic signal can be stored in order to provide an estimate of the traction characteristic of the surface in real time.

Abstract: The vehicle is provided with a slippage preventing apparatus and an automatic drive control device. The slippage preventing apparatus is designed to control a degree of slippage of the driven wheel of a vehicle so as not to become too large. The automatic drive control device is adapted to increase or decrease an output of the engine so as to allow a vehicle speed to reach a given value. The slippage preventing apparatus controls operation of the automatic drive control device when a degree of slippage of the driven wheel is controlled by means of the slippage preventing apparatus. Operation of the automatic drive control device is controlled by thoroughly suspending operation of the automatic drive control device or solely suspending its operation so as to increase the output of the engine.

Abstract: This controller detects acceleration slippage of driven wheels, calculates the controlled variable of the driven wheels based on the deviation of the actual driven-wheel revolution speed from the target driven-wheel revolution speed, starts controlling the driven-wheel revolution speed in response to the calculated, controlled variable, and corrects the calculated, controlled variable to control the driven-wheel slip mount out of a predetermined range due to excessive control of the driven-wheel revolution speed, thus making the actual driven-wheel revolution speed quickly approximate the target driven-wheel revolution speed.

Abstract: An acceleration-slippage controller having an instantaneous-slippage detector for maintaining a good acceleration of an automobile. After an acceleration-slippage control has started due to slippage detected at a driven wheel, the instantaneous-slippage detector determines whether the detected slippage is instantaneous. If the slippage is determined to be instantaneous, the acceleration-slippage control is immediately interrupted so that a long acceleration-slippage control cycle does not limit the acceleration of the automobile.

Abstract: This invention concerns a creepage control system for locomotives that optimizes adhesion while minimizing wasted energy, rail/wheel wear and shock loading on the drive train. The basis of the invention is to always maintain a small but positive value of the slope of the wheel-rail adhesion creep curve (or differential of adhesion versus creep) for all traction axles of the locomotive through microprocessor control. The value of the differential of adhesion versus creep is used to define an operating window for control and operation of motors continually in the optimum domain when high adhesion is demanded. When, due to a sudden increase in rail contamination, the value of the control function becomes negative, the microprocessor control reduces the generator excitation in stages until the function becomes positive and inside the operating window again. The microprocessor controls a rail cleaning system which is turned on or off depending on the cleanliness of the rail.

Abstract: An anti-skid braking system for a vehicle, having (a) hydraulic brakes for wheels of the vehicle, (b) actuators provided for respective brake groups each including at least one of the brakes, for controlling a braking pressure or pressures of the brake or brakes of the corresponding groups, (c) speed sensors, at least one of which is provided corresponding to each actuator, for detecting speeds of the wheels, and (d) to controller operable for: normally presuming that an actual speed of the vehicle is represented by a highest one of the detected wheel speeds; after a deceleration value of the highest speed has exceeded a preset upper limit, fixing the deceleration value of the vehicle at the preset upper limit, and presuming the actual vehicle speed based on the upper limit; and calculating a slip amount of each wheel based on a difference between the presumed vehicle speed and the detected wheel speed, to control each actuator so as to prevent the wheel from skidding.

Abstract: A wheel slip detection system which is especially effective in cases where a gentle or sluggish slip simultaneously occurs on all the axles of a vehicle. For instance, when the velocity difference (.DELTA.V) between the standard speed, namely, the maximum axle speed, of two or more axles exceeds the preset velocity, this condition is detected as a slip state. In the present system, the first and second velocity values V.alpha.1 and V.alpha.2 are set, and it is detected as a slip of all axles when the following (a), (b), (c) states occur at each axle wherein:(a) V.alpha.1<.DELTA.V,(b) Max. .DELTA.V<V.alpha.2,(c) Max. axle acceleration<Standard acceleration.

Abstract: A propulsion control device for a motor vehicle which has a permanently balanced all-wheel drive, wherein the drive slip thresholds at which the control responds in the sense of a braking action, is increased as a function of the velocity and decreased as a function of the transverse acceleration. The acceleration thresholds, at which the control responds, are lowered as a function of the transverse acceleration. In the case of travel in a straight line, the lowest of the wheel peripheral velocities is taken as the reference velocity relative to which the drive slip thresholds are fixed. In the case of travel in a curve, the average of the wheel peripheral velocities of the left-hand side and right-hand side vehicle wheels is taken as the reference velocity for the vehicle wheels on the left-hand side and the right-hand side of the vehicle, respectively. From the time t.sub.

Abstract: A DC voltage on an electric car stringing is supplied to a variable voltage and variable frequency PWM inverter so as to be converted into a three-phase alternating current which is supplied to a plurality of three-phase induction motors. The motors are connected to different wheels to drive an electric car. The inverter is controlled on the basis of an operating frequency command determined by adding or subtracting a slip frequency command to or from a motor speed and a voltage command proportional to the operating frequency command. On the other hand, a motor current command is set and compared with a maximum current value of currents of the plurality of motors, and the slip frequency command is corrected in accordance with a difference therebetween.

Abstract: To provide an unambiguously representative signal responsive to the speed of a vehicle wheel, an inductive pick-up (1a. . . . 1n) is coupled to a suitable star wheel or the like of each one of the wheels, the pick-ups then providing their signals to amplifiers (3a. . . . . 3n) having hysteresis characteristics. At low speeds, an offset signal is superimposed on the voltage from the inductive pick-ups so that the amplifiers respond and provide output signals only at higher amplitudes of the pick-up signals, thereby eliminating inaccuracies or disturbances occurring in the sensor which might simulate changes in speed of the respective wheel.

Abstract: An excessive slipping condition of one of the driven wheels of a vehicle that is indicative of a loss of traction of that wheel is sensed based on the difference in the driven wheel speeds. An increasing braking force is applied to the wheel with excessive slip to transfer driving torque through the differential to the non-slipping wheel so as to equalize the driven wheel speeds. In order to provide for compensation of the difference in wheel speeds that is not due to slip that occurs as the vehicle is turning, the speeds of the driven wheels are compensated based on the difference in speeds of the undriven wheels.

Abstract: Anti-spin control systems are useful, for example, in industrial off-road vehicles. It is desirable that such systems exhibit rapid response to adverse working conditions, and be capable of quickly applying braking forces to whichever driven wheel is rotating at a higher velocity at a given time. The instant invention includes an electrical circuit for producing first and second brake control signals having values responsive to a working condition wherein one of the vehicle wheels loses traction and rotates more rapidly than the other vehicle wheel. A first controllable valve receives the first brake control signal and responsively controllably engages a brake mechanism associated with the faster rotating wheel, while a second controllable valve receives the second brake control signal and responsively controllably moves a brake mechanism associated with the slower rotating wheel from a brake released position to a brake pre-engaged position.

Abstract: A method and device for controlling the variation of braking pressure in the wheel cylinders of brake-slip controlled vehicle brakes. The wheel rotational behavior (v.sub.Rad) and further a vehicle reference velocity (v.sub.Ref) are determined by sensors and logically combined to produce control signals. The braking pressure at the wheels is controllable by the operation of electromagnetically actuated valves (AV, EV) inserted in the pressure fluid circuit. A first pressure-decrease pulse is triggered as soon as the wheel velocity exceeds a deceleration or slip threshold during a braking action. The duration of the said pressure-decrease pulse is determined by the instantaneous deceleration upon attainment of the first switching threshold. Any subsequent pressure decrease pulse is delivered only after a predetermined waiting period and is of a duration determined by reference to the average acceleration.

Abstract: In a wheel slip prevention control system for preventing the slippage of the driven wheel occuring when a vehicle is accelerated, a reference speed is derived from the non-driven wheel speed and the driven wheel speed is corrected by a correction value obtained as a function of a driven wheel acceleration value and a non-driven wheel acceleration value. The throttle valve is controlled with speed corresponding to the slipping condition of the driven wheel, i.e., with a control speed derived as a function of the reference speed and the corrected driven wheel speed, so that the slippage is quickly and effectively prevented.

Abstract: A wheel-slip detection system and/or method for implementing self-readhesion or resticking viscous sticking phenomenon after all the wheels of a car have assumed a slipping condition. The detected data are self-retained until all of the wheel speed differences .DELTA.V become smaller than the first speed value .DELTA..alpha.2 regardless of the restoration of all wheel acceleration by the brake release application. Through this method, it is possible to prevent repeated occurrence of any simultaneous gentle or sluggish-slip state of all the wheels when self-readhesion application is not expected so that the increase of brake distance is avoided.

Abstract: A method of controlling the mode of driving an electric vehicle so that the electric vehicle is accelerated at a maximum acceleration and is decelerated at a maximum deceleration. The mode of variation of the running speed of the electric vehicle is estimated on the basis of the variation of the running speed of the electric vehicle calculated from the revolving speeds of the axles of the electric vehicle detected by revolving speed detectors associated with the axles, respectively. The axles are controlled for minute idle rotation or minute slip on the basis of the estimated mode of variation of the running speed of the electric vehicle to produce a maximum effective adhesion between the wheels attached to the axles and the rail so that the acceleration of the electric vehicle at a maximum acceleration and the deceleration of the same at a maximum deceleration are achieved.

Abstract: From the peripheral velocity v.sub.M of a driving wheel and vehicle velocity v, the changing rate .DELTA.v.sub.s /.DELTA.t of the relative velocity v.sub.s therebetween with respect to time is obtained. The changing rate .DELTA.f/.DELTA.t of the traction force f produced in the driving wheel at that time is obtained from a detected armature current of a motor driving the driving wheel. A driving torque produced by the motor is so controlled as to be decreased when polarities of the changing rate in the relative velocity and that in the traction force are different from each other.

Abstract: An anti-skid brake control system controls the operation mode of a pressure control valve in a hydraulic brake circuit for increasing the fluid pressure in its application mode, for decreasing the fluid pressure in its releasing mode and for holding the fluid pressure at a constant value in its holding mode. The control system has a predetermined operation pattern in which the operation modes of the pressure control valve cycle through a predetermined schedule. Measured wheel acceleration and slip rate values dictate which operation modes are to be selected next and when the change from mode to mode should be performed. When the operation mode is to be changed, the next operation mode selected is checked to see if it is consistent with that scheduled. When the selected operation mode is different from the scheduled one, the selected operation mode is modified to perform the operation according to the scheduled operation mode which would otherwise be skipped.

Abstract: Apparatus is disclosed for detecting wheel slip of a driven wheel with respect to a surface. A magnet is fastened to the wheel and a sensor coil is fixedly mounted adjacent the path of rotation of the magnet. The sensor generates one electrical pulse each time the associated magnet rotates past it. Thus, the time of rotation of the wheel corresponds to the time interval between the pulses provided by the coil. The rotation time of the driven wheel is compared against the rotation time of a similarly equipped free rolling wheel to detect wheel slip. A wheel slip indication is given if the difference in wheel rotation times is greater than a selected limit. Acceleration of the wheels may interfere with the wheel slip detection, because the rotation times of the driven and free rolling wheels are not measured at precisely the same time.

Abstract: A brake system with a control installation influencing the deceleration of the motor vehicle in such a manner that the deceleration of the vehicle takes place along a stored characteristic curve triggerable by a measuring element of the brake pedal.

Abstract: A system for controlling the propulsion on motor vehicles which not only enables the output torque of the drive unit of the vehicle to be utilized in an optimum manner in critical driving situations, especially under extreme road conditions, but also endows the vehicle with good stability and enhanced driving safety. A comparator is provided, in a propulsion control system which is triggered by at least one presettable or permanently preset threshold value of the speed of the vehicle, and generating an output signal causing the drive torque to be reduced, as soon as this threshold value is exceeded and a signal is present, which indicates that an individual wheel brake is being activated and/or that one of the driven wheels is tending to spin. The threshold value of the speed of the vehicle, which value governs the control process, is preferably regulated in accordance with the transverse acceleration which acts on the vehicle whenever it follows a curved path.

Abstract: Apparatus for use on a vehicle having a main drive shaft and first and second output shafts operable for providing driving torque to the wheels of the vehicle. The apparatus comprises electromagnetic sensors for determining excessive difference in output speeds of the first and second output shafts to detect a slip condition and a control circuit operable to actuate another mechanism for eliminating the slip condition in response to the sensing means. The other mechanism is operable for a predetermined time after actuation thereof.

Abstract: An instructing system for a four-wheel drive vehicle powered by an internal combustion engine comprises a transmission for transmitting power from the engine to two main driving wheels, a clutch for selectively transmitting the power to auxiliary two-wheels, and a select lever for engaging the clutch. Speed detectors are provided for detecting both the speed of the two main driving wheels and the two auxiliary wheels. An electric circuit compares both speeds and turns on a lamp when the difference between both speeds exceeds a predetermined level, whereby slipping of the two main driving wheels is indicated.

Abstract: A monitoring apparatus for a vehicle such as a tractor comprises a console including controls and a control circuit for calculating wheel slippage of at least one drive wheel of the vehicle and responsive to engine RPM of the vehicle and to the rotational speed of the drive wheel for calculating a predetermined relationship therebetween. The control circuit is also responsive to actuation of the controls for setting the calculated relationship equal to a predetermined reference value when there is substantially no load on the vehicle, and hence minimum slippage of the drive wheel, in each of a plurality of ranges of gear ratios of the vehicle, thereby calibrating the control circuit to calculate wheel slippage for each of these ranges of gear ratios. The console also mounts an observable indicator and the control circuit also calculates other variables such as vehicle speed and engine RPM and actuates the observable indicator when the calculated values deviate from preselected values.

Abstract: In the control of adhesion between a vehicle and a track, an adaptive control is provided for reapplying the tractive effort between the vehicle and the track in accordance with the known tractive effort level at which a loss of adhesion was sensed.

Abstract: An anti skid system for a wheeled vehicle, in which each of the two wheels on opposite sides of a vehicle axle is equipped with an independent brake pressure control system, each of which includes a wheel speed transducer, a processor and a brake force control valve assembly. In order to prevent the occurrence of yawing moments when the road surface adhesion coefficients are different for the two wheels, the control channels are interconnected in such a way that when one of the wheels exhibits a tendency to lock up, the rate of increase of the braking pressure in the opposite wheel is reduced. This reduction may be prevented if the other wheel also exhibits a tendency to lock up.

Abstract: A multi-application speed drop detector, for a high-speed bucket belt conveyor conveying powdery substances, that can automatically perform such functions as alarming, causing ordinary and emergency stops in accordance with the amount of speed drop of the belt conveyor from a set speed level, and eliminating the effect of an increased bucket pitch at a joint in the belt. A bucket passage detection signal produced by an electromagnetic induction sensor is used in order to avoid the ignition and explosion of the powdery substance being conveyed due to a slip of the belt.

Abstract: A slip control system for vehicles having spaced apart differentially driven wheels (200,202) including means (220) for calculating wheel slip according to the ratio of wheel speeds, means (242,230,232) for entering a slip control mode wherein a braking force is applied to the slipping wheel and incrementally varied on a periodic review basis according to recalculated slip values. If slip increases or holds steady, the brake force is incrementally increased. As slip becomes less, the brake force is incrementally reduced, the particular increments of force reduction being selected in accordance with successive measurements of slip. A drive shaft signal (226) is compared to the high wheel speed signal to identify a wheel speed transducer failure.

Abstract: An improved vehicle skid control braking system is provided of the type that selectively controls the engagement and disengagement of the brake system of the vehicle in accordance with selective braking conditions, such as vehicle, speed, wheel speed, road surface conditions, wheel speed "slip" conditions, etc.

Abstract: A skid control system which compares a current representative of wheel deceleration with an alterable reference current using an integrating comparator to control the brakes of a vehicle. The reference current has an initial value which represents a wheel deceleration indicative of an incipient skid condition and is increased to a substantially higher value after the current representative of wheel deceleration reaches the initial reference current value and is reduced to a very low value after a predetermined period of time. When the current representative of wheel deceleration exceeds the reference current by a predetermined degree as determined by the integrating comparator, the brakes are released. The brakes are reapplied after the current representative of wheel deceleration no longer exceeds the reference current at a time determined by the integrating comparator.

Abstract: An electronic antiskid control device which comprises a frequency multiplier of the phase locked-loop type, which receives repetitive pulses of predetermined frequency representing the speed of one wheel. The phase locked-loop multiplier normally outputs a second pulse signal, the frequency of which is normally equal to the frequency of the wheel speed signal multiplied by a given number. A digital counter which is periodically reset at a frequency equal to that of the wheel speed signal measures the number of pulses of the second pulse signal during each period. The measured number is transfered into a memory element and calculating apparatus responsive to the value stored in the memory element control an antiskid cycle. In operation under normal conditions, the number stored in the memory element is constant and has no action on the calculating apparatus.

Abstract: A digital speed detecting circuit of the type in which pulses of a clock frequency are counted during a time interval of a cycle of the sinusoidal signal obtained from a sensor of the rotating member whose speed is being measured. The pulse count throughout the speed range of the rotating member is adjusted to be within a range best suited for accurate evaluation, since the pulse count exceeds this range at high and low speeds. This is accomplished in a first embodiment by shifting to a different counting frequency in different speed ranges and correcting the speed signal obtained by a factor corresponding to the degree of frequency change. In a second embodiment, the counting frequency is monitored and adjusted each cycle of the sinusoidal signal by comparing in a shift register the stage of advancement of a binary counter that produces the pulse count with a reference stage establishing the upper limit of the evaluation range.

Abstract: A method for predicting vehicle speed in a braking control system for wheeled vehicles, where a signal representing wheel speed before braking is used to trigger charging of a capacitor in an electronic unit. The capacitor voltage is reduced during braking in response to a predetermined retardation value in order to correspond to an instantaneous value for the vehicle speed. The vehicle speed signal is compared with a wheel speed signal, which comparison triggers, when the wheel speed signal exceeds the vehicle speed signal, up-dating of the capacitor voltage level to a value corresponding to the actual wheel speed signal. When up-dating the vehicle speed signal, the preselected retardation value is gradually lowered by a value corresponding to the magnitude of the actual up-dating.

Abstract: The present invention is a brake actuating and brake system for maintaining a predetermined proportional relationship between the rotational speeds of vehicle wheels by both applying and/or releasing hydraulic fluid brake pressure, and distributing released pressure back into the brake system.

Abstract: A vehicle controlling device wherein an output signal proportional to vehicle velocity obtained from a vehicle velocity detector and an output signal proportional to wheel velocity obtained from a wheel velocity detector are to be compared by a comparator and the slip state of the wheel is to be detected from the result of the comparison, thereby to control a brake mechanism, characterized in that an adder circuit is provided which adds an output signal proportional to a predetermined wheel velocity at a low vehicle running speed to the output signal obtained from the wheel velocity detector and that the output signal of the adder circuit and the output signal from the vehicle velocity detector are compared by the comparator to ensure accurate brake control at all vehicle speeds.

Abstract: The inventive system comprises a magnetic pulse generator mounted on each axle of a railroad car. The outputs from the resulting pulse generators are fed to a detector which compares the speeds of the axles. When wheel slip indicated by a pulse count difference between axles is encountered, the detector operates solenoid-operated dump valves to increase brake pressure on both axles of the slipping axle truck. When axle speed recovers to a non-slipping condition, the dump valves are reset and brake pressure is reduced. The detector circuitry is also able to detect wheel slide thus permitting corrective action. In addition to the above, the system includes provision to prevent synchronous sliding of all axles by sensing the rate of change of count.

Abstract: A digital traction control system is disclosed for a motor vehicle having a plurality of driven wheels connected by a differential mechanism, characterized by the provision of a plurality of counters for counting pulses produced in accordance with the rotational velocities of the driven wheels, respectively, the counters being resettable when the count totals therein are within a given ratio. In the event that a driven wheel experiences a spin condition causing it to rotate at a higher rotational velocity than the other wheels, whereby the pulse count total of its associated counter exceeds the count total of the other counters outside the given ratio, a solenoid-operated brake is automatically activated to brake the faster wheel, thereby to transfer driving torque to the other driven wheel or wheels.

Abstract: An improved vehicle skid control braking system is provided of the type that selectively controls the engagement and disengagement of the brake system of the vehicle in accordance with selective braking conditions, such as, vehicle speed, wheel speed, road surface conditions, wheel speed "slip" conditions, etc.

Abstract: In a circuit for producing a digital wheel speed signal from the duration of a half cycle alternation of the sinusoidal waveform produced by a wheel sensor, there is provided a control unit which operates a first counter until it reaches a count corresponding to the duration of the half cycle alternation of the sinusoidal waveform and in response to this occurrence effects operation of a second counter until the first counter reaches a predetermined final stage. A signal representing the duration of a half cycle alternation, which is inversely proportional to the angular wheel velocity is thus converted by the control unit so as to produce a wheel speed signal that is directly proportional to the angular wheel velocity. According to the present invention, the pulse frequency supplied to at least one of the first and second counters is adjusted according to the stage of the counter so as to change exponentially and thereby provide for faster generation of the wheel speed signal.

Abstract: A digital phase-locked loop for speed measurement, in particular for use in antiskid control systems, for the conversion of the frequency of an input pulse sequence, proportional to a speed, into a digital numerical value to be used in the digital arithmetic unit for an antiskid control system is provided wherein there is a certain numerical value which will always be the same which is allocated to any input pulse sequence and which can be applied to a first storage register and added to the contents therein. At regular intervals, determined by a clock generator, a positive digital output numerical value is generated by a detector if the content of the first storage register is above a predetermined upper limit and a negative digital output numerical value will be generated if the contents of the first storage register are below a predetermined lower limit.

Abstract: This invention discloses a device for converting the rate of a pulse train which is proportional to the velocity of a vehicle wheel into a binary number for use in a digital computer for anti-skid control systems wherein the pulse train is supplied to a comparator, the output of the comparator being coupled to the input of a storage register which cumulatively adds to its contents, taking due consideration of the sign of the input. A frequency generator which is controlled by the contents of the storage register, with the comparison pulse train produced by the generator being supplied to the comparator and an adapter being added to establish a difference between the frequencies of the two pulse trains in the form of a binary number, which binary number is supplied to said register so that the content of said register represents the binary number corresponding to the frequency. The comparator and the register are both controlled by a clock pulse generator.

Abstract: A switched noise filter circuit for a skid control system which is adapted to filter out noise signals picked up by the wheel sensors as a result of brake squeal which often occurs at low vehicle speeds. Unfiltered, the sudden termination of a noise signal of this type could be interpreted as a rapid wheel deceleration by the skid control system causing a dumping of the brake pressure, resulting in an inadvertent release of the brakes.