Abstract: A gear speed measuring system which is capable of measuring speeds down to zero, which is capable of use in a rugged environment, and which is relatively insensitive to gear-sensor spacing. The system comprises an electromagnetic sensor (20) connected into the tank circuit of an oscillator (58) to produce an FM signal in which the frequency shifts occur in synchronism with the rotation of a gear (12) or the like. A detector (66) having a reference frequency input (68) converts the FM signal to a digital signal. A microprocessor (48) adjusts the reference frequency (68) as necessary to keep it between the high and low limits of the sensor output. The speed measuring system is applied to the control of the drive unit for a heavy off road vehicle (10) such as a tractor or earth mover.

Abstract: Disclosed herein is a digital read-out meter circuit including a digital read-out meter and a frequency multiplier arrangement for providing signal pulses coupled to the input of the digital meter counters, said signal pulses having a frequency so that the parameter value to be displayed can be counted and read out directly by the meter. A presetable up/down counter provides an output representative of the rate of change of the parameter value to be displayed, and a logic circuit arrangement is operable, subject to the up/down counter output, for allowing application of different frequency data update pulses to the data update strobe terminal of the meter so that the meter automatically switches from a slow to a fast data update rate when the rate of change in the parameter exceeds a predetermined limit.

Abstract: A speed measuring apparatus is provided for indicating a percentage of noal full speed RPM of a jet engine and also for indicating time required for accelerating and decelerating the engine. A generator output is converted to a square wave and a time interval measurement is made between zero crossings of the square wave. The square wave controls the starting and stopping of a time period counter and measured time is converted to percent RPM which is displayed on a digital incandescent display. Similar time periods are measured when the engine is advanced from idle to full power, and also when the engine is retarded from full power to idle.

Abstract: An electronic device particularly useful as a jogging computer comprises presetting means for presetting the size of the user's step, an inertia sensor sensing each step, a central clock, and a microprocessor computing the user's speed and distance travelled, and displaying same on an electronic display. The described device further includes a pacer which produces a tone at a preselected rate to aid the jogger in pacing himself. A second embodiment of the invention is described for attachment to a bicycle for measuring speed and distance travelled of the bicycle.

Abstract: A speed and direction detector for rotating bodies such as gears (10) including a pair of spaced sensors (14) mounted adjacent the gear teeth (12) to develop phase-shifted alternating signal waveforms, and a decoder (20) to develop a sequence of output signal conditions (S0-S3) depending upon the relation between the alternating waveform values. Signal stage memories (26, 28, 30, 32, 34, 36) utilizing flip-flops and gates connect the decoder outputs to an up/down counter (42, 44) which is incremented or decremented according to gear rotation direction only if a complete signal condition sequence occurs.

Abstract: A rotational speed measuring system comprises a rotatable member with calibration segments and a marker portion both provided along the periphery of the rotatable member, pick-ups for producing a pulse train signal in response to passage of the calibration segments and the marker portion when the rotatable member rotates, an electrical circuit for producing calibration pulses and marker pulses in response to the output signals of the pick-ups, a monostable multivibrator responsive to the marker pulse to produce a pulse signal of a predetermined pulse width, and a counter responsive to the calibration pulses for a period of time defined by the pulse width of the pulse signal from the monostable multivibrator. The counter counts the number of the calibration pulses corresponding to calibration segments which are equidistantly spaced from each other, thereby producing an output signal indicative of the rotational speed of the rotatable member with high accuracy.

Abstract: A probe is constructed for placement in the hot turbine section of a gas turbine engine. A housing containing two electrodes extends through the turbine shroud into the tip clearance area of the turbine rotor. A voltage impressed across the electrodes will generate an electric field in the vicinity of the turbine blades which will be distorted as the blades pass, thereby generating a charge pulse at the output of the probe. The electrode conductors are imbedded in pins which are retained by insulating rings brazed in place. The electrodes extend slightly outward from the surrounding insulating surfaces to create an air gap around each electrode. This air gap provides additional insulation and prevents contamination.

Abstract: An apparatus for detecting and controlling an elevator speed which includes a rotary disc rotated by a motor which moves an elevator cage and including a pulse generator which produces a pulse signal proportional to an elevator speed in cooperation with the rotary disc. The pulse signal is differentiated by a differentiation circuit and the output signal of the differentiation circuit is rectified by a full-wave rectifying circuit with the output signal of the rectifying circuit supplied to a monostable multivibrator. The output signal of the multivibrator is smoothed by a smoothing circuit which thereby produces an analog speed control signal. The multivibrator includes a zener diode operating to decrease the voltage level of the smoothing circuit output should the power source voltage drift. The rotary disc has projecting portions and apertures between the projecting portions all of which are of the same shape and width.

Abstract: A transducer for measuring the velocity and displacement of ferromagnetic materials comprising first and second magnetic read-heads positioned close to but not contacting the magnetic element whose velocity is to be measured with the two read-heads located a fixed distance apart in the direction of travel of the element, magnetic means positioned close to the magnetic element ahead of the first and second read-heads in the direction of travel of the magnetic element for increasing the magnetic surface noise levels of the material or the magnetic element, amplifiers connected to the two read-heads for amplifying the random voltage noise signals induced in the read-heads, said signals being substantially identical with one being delayed in time with respect to the other, zero-crossing detectors connected to the outputs of the amplifiers, means for correlating the noise signals obtained from the zero-crossing detectors and providing an output frequency signal, an electronic digital delay line circuit connected b

Abstract: An amplifier circuit for use with Hall effect and other similar type sensors whereby the circuit is conditioned by the cyclical signal input from the sensor and sets a threshold level based upon the signal input from the sensor, so that the signal output from the circuit is a voltage replica of the input signal, but modified to have a predetermined and constant high and low peak values without regard to peak value variations of the cyclical input signal.

Abstract: A time-constant circuit is employed for gradually decreasing the voltage of an input signal carrying information to be indicated by a deflecting coil type meter so that the voltage of an input signal applied to the following driving stage does not abruptly drop to zero although the power switch of the driving circuit is turned off. A timer circuit responsive to the power switch energizes a relay or a switching circuit to supply the driving stage with electrical power not only for the time that the power switch is on but also for an additional interval after the power switch is turned off so that the driving stage is capable of being responsive to the gradually decreasing voltage causing the pointer of the meter to return to the zero point.

Abstract: A tachometer for monitoring several functions on an implement, such as engine, shaft and ground speeds. A microprocessor receives a-c input signals which vary in frequency as the shaft or ground speeds change. A time window synchronized with a rising edge on the desired input signal is provided during which the number of falling edges are counted. A running total weighted average of a number of successive counts is used to update a digital readout indicating speed. Each new count is compared with the previous average and, if a sudden speed change occurs, the processor shifts to a fast update mode in which the new count is used to immediately update the readout. Programming switches are provided for selecting the proper ground speed time window for a given tire size and for providing a ground speed indication in either kilometers per hour or miles per hour.

Abstract: In a detecting apparatus for indicating engine revolutions or vehicle speed, a counter is provided to count up, for a predetermined period of time, the number of pulses produced by an angle sensor. To improve the accuracy of the measurement, the time width during which the pulses are counted can be varied in accordance with a rotational speed of the engine. In this way, a larger measurement time period is provided at lower speeds than at higher speeds.

Abstract: An apparatus for obtaining a signal relative to rotational speed of a rotary element is disclosed. The apparatus comprises a permanent magnet and a magnetic body which relatively approaches or moves away from the permanent magnet according to the rotational speed of a rotary member. A magneto-sensitive switch is operated in response to the change in intensity of the magnetic field produced by the relative motion between the permanent magnet and the magnetic body. Therefore, there can be obtained an apparatus which is small in size and high reliability.

Abstract: A multi-function device using two ICs, with the precision ignition pulse frequency-to-voltage converted signal produced in the RPM portion being used as input to both ICs. Chatter pulses produced by an operational amplifier in the RPM limiter are utilized to shunt ignition pulses to ground in a proportional manner as engine speed approaches the selected maximum.

Abstract: An A.C. voltage picked up from the alternator driven by an internal combustion engine is converted into a pulse train signal so that the number of the pulses is counted for a period of time defined by a reference timing signal produced in synchronization with the rotation of the crankshaft of the engine. When the number of the pulses reaches a predetermined value during the period of time, a counter produces an output signal to indicate that the slipping rate of the belt is within a tolerance. On the other hand, when the number of pulses is less than the predetermined number, the counter does not produce an output signal (indicating that the slipping rate is over the tolerance). The output of the counter may be averaged over a plurality of measuring times.

Abstract: A rotatable disk having a plurality of calibration segments and at least one marker along the peripheral portion thereof is provided while a stationary pick-up provided adjacent the disk for generating a first signal indicative of calibration segments and a second signal indicative of a reference position of the rotation of the disk. The frequency of the first signal is increased in order to accurately measure the rotational angle from the reference position.

Abstract: Bearing assemblies with inner and outer races and rolling elements therebetween incorporate local sensing means for producing a signal indicative of the movement of one of the races relative to the other. The sensing means is mounted in close proximity to one of the races and is usually directly secured to the race intended to be stationary. The sensing means can be mounted laterally of the bearing races or radially inside or outside of the bearing races.The sensing means may employ an inductive or capacitive sensor and oscillatory means and a body or component, such as a disc, carried by the movable race creates an influence detected by the sensing means to provide the signal. In other constructions the sensing means detects changes in electromagnetic radiation or fluid pressure created by the component or body carried by the movable race.

Abstract: An apparatus and a method for measuring the velocity of a moving dielectric material including establishing an electric field within the dielectric material to polarize the material; establishing a magnetic field within the dielectric material to induce a velocity-dependent torque on the electric dipole moments tending to align the electric dipole moments perpendicular to both the direction of motion of the dielectric material and to the direction of the magnetic field; detecting the change in the polarization of the moving dielectric material induced by the magnetic field; and determining the velocity of the moving dielectric material in response to the detected change in polarization.

Abstract: A fixed interval, variable period technique for measuring pulse rate including defining the start and the end of a fixed measuring interval, counting the pulses whose rate is to be measured beginning in response to the start of the measuring interval and stopping in response to the end of the measuring interval; measuring the period of time between the occurrence of the first counted pulse and the last counted pulse; and dividing the number of pulses counted during a measuring period by the period to determine the pulse rate.

Abstract: An onboard unit consisting of a tape recorder, and associated data handling components utilized to provide records of vehicular operating information including speed, distance, power level, braking level, traction motor current and other control events. Each quantity is associated with an incremental distance and/or time which is fixed. In the case of a rail guided vehicle, location signals provided by ground mounted markers are also recorded. Summation of incremental distances as determined from each marker provides an exact location. A magnetic tape unit provides both data storage and operations instruction for a microprocessor based system, allowing convenient alteration or variations in unit function without internal modification. Each unit retains a unique non-volatile serial number which is transferred to each tape allowing convenient correlation of recorded tapes to onboard units.

Abstract: A pulse generator of the corona discharge type for sensing engine crankshaft angle in an engine control system having a rotor with a plurality of pulse generating elements angularly spaced about the rotor axis. In order to generate as many pulses for each revolution of the rotor as desired to permit accurate measurement of the angular displacement of the rotor axis from a reference point, the rotor is constructed of a disc having a plurality of angularly equally spaced apart segmented regions to act as the pulse generating elements, and at least one electrode is stationarily mounted with respect to the disc to form an air gap to generate corona discharges thereacross in succession in cooperation with each one of the segmented regions upon rotation of the disc. An impedance element is provided to develop a voltage signal in response to the generation of the corona discharge.

Abstract: A digital transducer for rotary shaft speed has a resolution which varies automatically with shaft speed. A wheel, keyed to the shaft, is partitioned into plural sectors by angularly spaced notches, the angular spacing between successive notches increasing in a fixed ratio to define respective preselected speed zone within a range of such zones. A first counter is arranged to count fixed frequency clock pulses and to be reset after each shaft revolution. A variable frequency pulse train is generated by a sensor arranged to sense the passage of each notch. Upon receipt of each pulse in the variable frequency pulse train, a comparator compares the count in the first counter with stored reference numbers which are related to the clock pulse frequency and to the ratio of successive angles between the notches. A second counter, also reset once during each shaft revolution, counts pulses in the variable frequency pulse train.

Abstract: A system for indicating measured values, particularly the speed of movement of a motor vehicle, includes a pulse generator generating pulses having a frequency corresponding to a measured value, a counting circuit including first and second counters for counting pulses generated during successive time intervals to produce a pulse count signal for each time interval, a comparator comparing the pulse count signals from successive time intervals to produce a pulse difference signal corresponding to the difference therebetween, a memory for storing the pulse difference signal and transmitting the pulse difference signal to a stepper motor, and a pointer driven via gears from the output of the stepper motor to produce an indication of the measured value.

Abstract: A speed alarm system for a motor vehicle comprises a speed sensor, a plurality of comparators responsive to the vehicle speed and respective preset reference speeds, and a plurality of lamps responsive to the output signals of the comparators. The threshold values which are defined by said reference speeds, are stepwisely arranged to change the number of the lamps energized. The number of energized lamps varies in accordance with the difference between the vehicle speed and a reference speed.

Abstract: As documents are moved serially past a servo motor-driven endorser, it endorses a stamp upon each. A transport signal dependent on document speed, and an endorser signal generated by an optical tachometer mounted to the servo motor, provide input to a frequency comparator. The output of the comparator is a control signal which controls the servo motor speed to adjust the endorser rotational surface velocity to equalization with the document speed. Logic circuitry sets the endorser at a zero angular position. Responsive to an endorse command, the endorser is accelerated to document speed, receives ink from a supply roller, then endorses the passing document. A counter and a digital comparator in cooperation with the tachometer signal completion of the endorsement whereupon the endorser is decelerated and placed in the zero position.

Abstract: Electronic signal processing circuitry for use in the ignition system of an internal combustion engine is disclosed herein. A signal generator which receives crankshaft position pulses from a sensor and produces periodic outut pulses which have durations equal to a constant percentage of the period of the input sensor pulses is disclosed. The generator includes a crankshaft position sensor feeding a bistable flip-flop which controls a dual slope integrator circuit having its output coupled to a comparator with the comparator output coupled back to the reset terminal of the flip-flop. The generator produces pulses at the output of the flip-flop which have durations equal to a constant percentage of the period of the crankshaft position sensor pulses.

Abstract: A method of and an apparatus for converting a first series of pulses into a second series of pulses having a frequency proportional to the frequency of the first series. The method and apparatus are particularly useful for providing a series of equally spaced pulses representative of the speed of a rotating gear in revolutions per minute (RPM). A proximity detector provides a pulse as each tooth of the gear traverses the face of the proximity detector and a sample period is formed by the passing of several teeth. A series of pulses is counted by a counter for the length of the sample period. The number of pulses at the end of the sample period is stored in a latch. A programmed divider counts down from the count in the latch to zero at a reference frequency and an output pulse is provided each time the programmed divider reaches zero. The programmed divider is reset to the count in the latch upon the occurrence of each output pulse.

Abstract: Vehicle speed measuring apparatus employing separate measurement of elapsed time and distance to obtain average vehicle speed in which provision is made for providing signals representative of a calibration factor which can be utilized to correct the distance signals to a number representative of true distance.

Abstract: A digital hourmeter-tachometer for use with internal combustion engines or the like comprises a programmable timer for outputting system timing pulses when a d.c. power source is applied thereto. A pick-up pulse circuit generates pulses indicative of the angular speed of the device being monitored and outputs d.c. power to the remainder of the hourmeter-tachometer. A first multiple decade counter counts hour pulses outputted by the timer. A second multiple decade counter counts pulses indicative of angular speed. Display means sequentially display the output of the stored count in the first and second multiple decade counters in response to system timing pulses. A long-life battery applies a direct current to the first counter when the pulses are not received by the pick-up circuit for providing a d.c. source thereby holding the hour count. Preferably, an overspeed shut-down circuit is integrated with the above described circuit.

Abstract: A method of determining average speed of a cyclically loaded rotating shaft, and an electronic tachometer for practicing the method. The revolutions of the shaft are counted electronically, a highly time-regular pulse stream is provided, and simultaneously with the counting of the shaft revolutions, the number of pulses in the pulse stream is counted over a time span of between 2 and 120 seconds. Then, the number of revolutions counted is electronically divided by the number of time pulses counted during the time span of 2 to 120 seconds to determine average speed, the speed so determined is digitally displayed, and the revolution and time pulse counting cycles are restarted. The accuracy of the average speed displayed is .+-.0.05%.+-.1 count when the time span is 2 seconds, with a resolution of 0.1 rpm.

Abstract: Disclosed is a device for measuring the rotational speed of a diesel engine. The device comprises a sensor element of electrostrictive effect type adapted to be detachably mounted on a delivery pipe of a fuel injection system of the diesel engine and having an intrinsic resonance frequency between 100 KHz and 10 MHz. A high frequency electric signal is transmitted from the sensor element in response to a high frequency oscillation generated in the fuel within the delivery pipe when fuel is injected. The device further comprises an amplifier, a converter, a wave shaping circuit, an integral circuit and an indicator. The high frequency electric signal is processed in the device and the rotational speed of the diesel engine is indicated by the indicator.

Abstract: A circuit is disclosed for driving an electronic speedometer (or tachometer) and an associated odometer of the type suitable for use in automobiles, trucks and tractors. The circuit includes a programmable divider which can be user calibrated so that a change in a system parameter, such as tire size, can be accommodated. The circuit employs a pulse generator producing timing pulses for a magnetically driven air core gauge. The timing pulses are produced in response to pulses indicative of the remote condition being sensed as, for example, wheel rotation or engine speed.

Abstract: A speed measuring circuit for digitally determining the angular speed of a rotating object employing a sensor and control unit for producing a sequence of signals proportional to the speed of the rotating object and for measuring the speed which is inversely proportional to the cycle duration. A storage register for storing a certain number of fixed values which are associated with certain speed values and which are graduated as preset of a predetermined speed measuring range. A comparator and control unit for comparing the cycle duration value measured each time with the fixed values and for setting the measured value equal to one of two successive speed step values when the measured value falls within the speed interval which is limited by the two successive speed step values.

Abstract: A digital speedometer is provided for use in an automotive vehicle and includes a transducer for connection to a conventional speedometer cable driver. The transducer is equipped with an optical encoder that produces electrical pulses in response to rotational motion of the speedometer cable driver. The electrical pulses are transmitted to a counting circuit which is reset by a variable reference oscillator. The frequency of the oscillator is much lower than the frequency of pulses from the transducer. Accordingly, a number of pulses from the transducer indicative of the speed of the vehicle are tabulated by the counting device during intervals between reset pulses from the reference oscillator. The period between reset pulses is determined by an adjustment to the oscillator to vary the output frequency thereof. The number of counts tabulated during each period is passed to a visual display.

Abstract: A digital speedometer for indicating angular or linear velocity has an index counter to control update of the displayed velocity. The purpose of the index counter is to prevent undesirable fluctuation of the displayed velocity where minor variations in velocity being measured have occurred. The digital speedometer uses a pulsating input signal having a frequency proportional to the velocity to be indicated. An oscillator circuit provides a clock frequency that is utilized in generating a counting period electrical signal. During the counting period, the input pulses proportional to velocity are gated into a counter. After each counting period, a comparison is made between the count currently being displayed and the count stored in the counter. If a difference occurs, the index counter is incremented. Only after the index counter has been incremented a plurality of consecutive times is the display permitted to be updated.

Abstract: A digital speedometer for indicating angular or linear velocity has an index counter to control update of the displayed velocity. The purpose of the index counter is to prevent undesirable fluctuation of the displayed velocity where minor variations in velocity being measured have occurred. The digital speedometer uses a pulsating input signal having a frequency proportional to the velocity to be indicated. An oscillator circuit provides a clock frequency that is utilized in generating a counting period electrical signal. During the counting period, the input pulses proportional to velocity are gated into a counter. After each counting period, a comparison is made between the count currently being displayed and the count stored in the counter. If a difference occurs, the index counter is incremented. Only after the index counter has been incremented a plurality of consecutive times is the display permitted to be updated.

Abstract: A single proximity probe coil driven by a high frequency source excites eddy currents at the periphery of a conducting disc having one or more stair - stepped perturbations and detects the changing radial levels or distances of the perturbations as the disc rotates. The detected signal is processed to yield output signals representing shaft speed and direction of rotation.

Abstract: Apparatus for controlling an odometer and speedometer system of a vehicle, adjustable for vehicle parameter variations, such as tire size and axle ratio, including a transducer for generating a plurality of initial pulses in response to vehicle movement which pulses control both the vehicle odometer and speedometer. The initial pulses are multiplied by a multiplying factor to produce a train of pulses for each initial pulse. The multiplying factor is in binary form and is selected either according to the position of an array of switches or according to a number retained in a programmable downcounter. The train of pulses is divided by a fixed number to create a driving signal for the odometer and is converted by a frequency converter to drive the speedometer.

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 proposed digital device for measuring instantaneous parameter values of slowly varying processes comprises a time-to-voltage converter. The first output of said converter is connected to the control input of a hyperbolic function generator and the second output of said converter is connected to the command input of the hyperbolic function generator. The hyperbolic function generator comprises a controlled pulse generator, with a linear modulation characteristic, and a start-stop circuit. The first input of the start-stop circuit is connected to the output of the controlled pulse generator and its second input is connected to the command input of the hyperbolic function generator. The output of the start-stop circuit, which is the output of the hyperbolic function generator, is connected to a counter-indicator unit. The device of the present invention sharply reduces the measurement and analysis time and makes it possible to connect measuring instruments to a computer.

Abstract: Electronic circuitry senses motion of a load bearing movable element which has a speed relationship as a function of load by establishing a sequence of timing pulses varying in inter-pulse duration time as a function of the movement speed and processes those pulses to produce electronic indicia signals used for control or display purposes. Sampled timing pulses are taken from the sequence to generate a control pulse of predetermined time duration. The control pulse duration is compared with the speed or loading signal comprising a pulse of time duration between sequential timing pulses thereby to produce an indicia analog signal variable over a range of load conditions. The indicia signals is used for display or control functions responsive to the load borne by the movable element within a predetermined analog range.

Abstract: A digital tachometer arrangement in which pulses resulting from rotation of a shaft, are counted over a predetermined time interval. The time interval is established by counting pulses from a high frequency oscillator. The counting of pulses from the high frequency oscillator is begun only at a predetermined instant when the pulses from the rotating shaft attain a positive edge. Relating the beginning of the time interval precisely to a predetermine edge of the pulses from the rotating shaft, provides for a stabilized display which counts the pulses from the shaft during the preset time interval. The count of the pulses from the rotating shaft over the preset time interval, is proportional to the rotational speed of the shaft, and is displayed on a digital readout connected to a binary-coded decimal counter receiving pulses from the rotating shaft.

Abstract: This disclosure relates to a system for sensing the speeds of one or more movable members and selectively displaying one of the speeds. The system includes a speed sensor associated with each moving member and providing an output that is a function of the speed. A mode selector circuit directs one of the outputs to a multiplier circuit that converts the output to a form which is displayed or indicated in the desired system of units. The mode selector circuit sets up the system for one mode of operation upon initial energization but may be changed to a different mode by a sealed contactless switch. The multiplier circuit is programmable using an externally adjustable code device. The display automatically adjusts for different requirements in each of the modes and for different external operating conditions.

Abstract: A speedometer-odometer apparatus is described comprising an encoding apparatus for generating pulses as a function of the distance a vehicle is moved, a calibrating apparatus and an indicating circuit means for visually indicating the distance and speed of the movement. Coupled between the encoding apparatus and the indicating circuit means, the calibrating apparatus is provided for controlling the number of pulses delivered to the indicating circuit means from the encoding apparatus so that the indicating circuit means will provide a predetermined output when the vehicle in which the apparatus is mounted is moved a predetermined distance. For providing a highly accurate and direct readout of the distance, there is provided, in the indicating circuit means and coupled to the output of the calibrating apparatus, a plurality of division circuits.

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: 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 tachometer which can operate to count the revolutions of any rotating device for which an electrical signal the frequency of which is related to the speed of rotation can be obtained is disclosed. The tachometer includes means for `normalizing` the input signal to provide a pulsed signal having a predetermined relationship with the speed of rotation, main counting means for counting the pulses, and means for displaying the accumulated count. The counters are controlled by logic circuits to count for a predetermined counting interval and the digital display is updated at the end of each counting interval. In addition to the main counting means there are provided interpolation means for generating a signal representing the number of revolutions performed by the device under test in the interval between each successive pulse of the "normalized" signal, to improve the accuracy of the tachometer.

Abstract: Circuitry for developing a binary number proportional to the frequency of an input signal includes a first and second shift register and an adder. Timing control circuitry establishes a 16 bit computation period and also develops a fixed binary number. Circuit means are provided for interconnecting the adder and the firsrt register for increasing the content of the register by the fixed binary number once each cycle of the input signal and for reducing the content of the register by a fixed proportion each of the computation periods occurring during each cycle of the input signal. The content of the first register is transferred to the second or buffer register each cycle of the input signal and display means are provided for displaying the input frequency of a function as the binary number contained in the second register.

Abstract: A wheel speed measuring apparatus is provided for use in an anti-skid brake control system such that a digital speed signal is obtained having good accuracy without resorting to expensive manufacturing methods to assure exact conformity of the teeth and teeth spaces of the rotor member of the wheel sensor device used in the anti-skid control system. The speed measuring apparatus consists of at least two corresponding portions, each consisting of a control unit, a counter and a data register. The control unit of one portion responds to a positive polarity transition of the square wave signal generated by the wheel sensor, while the control unit of the other portion responds to negative polarity transitions, to initiate operation of the respective counters.