Abstract: The pulse tachometer for measuring the rotation of a rotating element (A) is characterized in that it comprises an inductive proximity sensor (10) placed in the vicinity of this element (A) in order to generate an electric pulse (100) upon each revolution of the element (A), a sender (20) connected to this sensor (10) for receive this electric pulse (100), shaping it and converting it into an optical signal, an optical-fibre link (30) connected to this sender (20) and to a receiver (40) for receiving this optical signal from the sender (20) and routing it to this receiver (40) in order to use it so as to calculate the speed of the rotating element. Application to rotating machines, for example turbine generators.

Abstract: A non-linear scale instrument responsive to a sensor which generates an output signal proportional to the magnitude of a changeable condition. A visible scale includes spaced gradations over the total extent of the scale, with spacings between pairs of scale gradations varying across the scale. A control circuit, in response to the output signal of the sensor, determines the angular position of and drives a rotatable pointer across the scale to the angular position corresponding to the magnitude of the condition measured by the sensor. The control circuit also automatically converts between different measurement units at the user's selection to re-position the pointer corresponding to the measured condition in the selected units.

Abstract: A magnetic-field-to-voltage transducer includes a Hall element and a digitally gain-controlled Hall-voltage amplifier that produces an analog voltage Vsig having excursions of one polarity corresponding to the passing of magnetic articles. Vsig is applied to the input of a signal-manipulating circuit that generates a proximity- detector binary output voltage, Vout, having transitions of one direction each time a predetermined point is reached in Vsig. A digitally gain-controlled gain amplifier is connected to the Hall element. A comparator circuit generates a binary signal Vbig (or V.sub.toobig) that changes from one to another binary level each time that Vsig exceeds a DC target voltage, V.sub.TG.

Abstract: A magnetic detection device including at least one oscillator circuit having a magnetoresistance element which converts a change of magnetism detected into a digital signal and a comparator for comparing the digitalized oscillating frequency of the oscillator circuit with another digitalized oscillating frequency generated from another oscillating circuit by taking a ratio thereof or by detecting a phase difference between the pulse signals. Utilizing the magnetic detection device, the amount of change of magnetism can be stably detected with a high accuracy within a wide range of ambient usage temperatures. The physical quantity detection device includes a magnetic detection device which can detect any physical quantity with a high accuracy.

Abstract: A method balances wheel speeds for a motor vehicle having a wheel-slip control system. Quick coarse balancing with respect to a reference wheel are provided in stages and subsequent fine balancing in pairs of wheels, either on the same side or on the same axle. Cornering is not detected from the left/right deviation of an axle, but from the temporal variation in the differentiated left/right deviation to achieve a very sensitive and reliable wheel balancing.

Abstract: A collective drive IC having a drive circuit for driving an electronic integrated distance indicator that indicates distance travelled by a vehicle is mounted on a wiring board together with the electronic integrated distance indicator. Drive circuits for driving a speedometer for indicating travel speed of the vehicle and a tachometer for indicating the number of revolutions of an engine are incorporated in the collective drive IC. The wiring board that has the collective drive IC and the electronic integrated distance indicator is accommodated in a single case to form an odometer unit. The odometer unit is releasably mounted on a meter case to which a main wiring board is fixed.

Abstract: A Hall transducer produces a signal Vsig. Threshold voltages V.sub.Pth and V.sub.Nth are generated at the beginning, t.sub.update, of each of a succession of update time intervals, of 64 pulses in Vsig, to be fixed percentages respectively of the peak to peak voltage in Vsig. A proximity-detector binary output voltage is high when Vsig exceeds threshold voltage V.sub.Pth and low when Vsig is below threshold voltage V.sub.Nth. Signals V.sub.Pold and V.sub.Nold, generated by first and second DACs, are equal to the first positive and negative peaks in Vsig after each time t.sub.update initiating the start of a successive interval. Signals V.sub.Pnew and V.sub.Nnew, simultaneously generated by third and fourth DACs, are equal to the greatest positive and negative peak voltages in Vsig during the interval ending at t.sub.update. Counters present their count to the first and second DACs that count pulses from a clock for tracking and holding +/- peaks in Vsig. After each time t.sub.

Abstract: Rotational speed of a vehicle speed detecting gear 1 is detected by a detection element 2 using an MRE or the like and the detected signal is waveform-shaped by a waveform shaping circuit 3 to serve as a vehicle-speed pulse signal. The cycle of the vehicle-speed pulse signal is detected by a sampling circuit 4. The detected cycle of the pulse signal is multiplied by a predetermined multiplier in a multiplication circuit 6 and the multiplication result is divided by a predetermined divisor in a diving and pulsing circuit 8. Then, a pulse signal having the cycle equivalent to the division result is output as a divided vehicle-speed pulse signal.

Abstract: An engine monitor includes, in a self-contained preferably sealed unit, a spark sensor, inductively and capacitively coupled through the case to a spark pick up wire, a timer, and a running time detector, responsive to inputs from the spark pick up to provide total running time, job time, and service time metering. Preferably, storage means are included for storing maximum RPM and spark mode data, that is, data indicating the number of firings per RPM for the particular engine, as well as a preset service interval and one or more auxiliary timers.

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

Abstract: A device which reshapes sinusoidal signals with a singularity to generate square-wave signals and detects the singularity in an unambiguous and reliable manner. The sinusoidal pulses are reshaped into square-wave pulses in such a way that the edges of the square-wave pulses always occur at the same location regardless of the height of the sinusoidal signal. This is achieved in that a change in the edges of the square-wave signals is initiated whenever the sinusoidal signal crosses the zero-axis. The required signal processing and logical comparisons, which also enable a definite detection of reference marks, are carried out in a suitable circuit arrangement.

Abstract: A method and a device for detecting rotational speed with an inductive sensor in which a sinusoidal potential is induced by a magnet wheel and then fed to a filter with a comparator connected downstream of the filter and therefrom into a square-wave signal that is essentially proportional to the rotational speed of the magnet wheel. This output signal of the comparator is evaluated in a microcomputer. In this evaluation, only the same type of edges of the comparator signal are evaluated, specifically those in which the intervals fluctuate less when considered over a certain time span. The microcomputer here can initially evaluate both types of edges, that is, positive and negative edges, and then use those edges in which smaller fluctuations, that is, interference, are determined for calculating the rotational speed. The microcomputer can also first evaluate only one type of edges and change over to edges of the other type only if the former displays interference above a present value.

Abstract: In a circuit arrangement for measuring a starting of rotation of a generator having an exciting winding and three-phase windings, a voltage regulator regulates an output voltage of the generator by influencing an exciting current, the three-phase windings are connected to one another at a point, one of the phase windings is connected to ground via a first resistor, another of the phase windings is connected to ground via a second resistor, a voltage across the first resistor is evaluated as a rotational-speed-dependent alternating voltage, this voltage is compared with a threshold voltage, and the starting of the rotation of the generator is detected when the measured voltage exceeds the threshold voltage.

Abstract: A measuring method for vehicles equipped with an internal combustion engine, the engine including a starter battery and a driven staffer motor used when an attempt is made to start the engine, is disclosed. According to the method, a voltage across a measuring shunt inserted in a current circuit between the battery and the starter motor is repeatedly measured, at a sampling rate, during each revolution of a crankshaft of the engine during activation of the starter motor. Corresponding values of a current delivered from the starter battery to the starter motor are derived from voltage measuring results. Values of the current are registered in a memory of a measuring computer. The registered values are used to establish a status of the combustion engine and its starting system. A value of a derivative of a rotational speed of the combustion engine crankshaft is obtained from the registered values.

Abstract: The invention relates to a sensor for the measurement of movement, with a preferably rotarily movable transmission unit (rotor) for indicating movement and with a stationary device (stator) for the generation of an electric signal for sensing the movement of the transmission unit. The measuring device includes a measuring element which is fixed within a measuring element chamber defined by a two-part housing. A carrier housing fixes the measuring device relative to the transmission unit and accommodates electric connections from the measuring device and surrounds the two-part housing at least in part.

Abstract: A method of selecting a pinion for a vehicle speedometer system uses a transmission output speed sensor and a transmission controller which applies a pinion factor to the signal from the sensor to generate an output signal representing the speed of the vehicle.

Abstract: To prevent a great variation of a detected wheel velocity for a period of time after a front wheel sensor or a rear wheel sensor for detection of a wheel velocity actually fails until a microcomputer detects the failure, it is determined whether or not an output pulse period of a front wheel sensor is equal to or shorter than a predetermined period. When the output pulse period exceeds the predetermined period, it is determined that there is the possibility that the front wheel sensor may be in failure, thus a front wheel velocity for a predetermined number of control cycles before (a front wheel velocity before the failure) is adopted as a front wheel velocity of the present control cycle. Also, a rear wheel velocity is calculated in a similar manner. For a time after a failure actually occurs until the failure is detected by a microcomputer, driving force control is not started even if other starting conditions for driving force control are satisfied.

Abstract: A vehicle speed measurement system (8) and method for driving a vehicle speed display responsive to a vehicle speed signal (300-334). A vehicle speed signal having a period corresponding to distance traveled by a vehicle is counted each first predetermined time period to provide a count (300-314); a preselected number of the counts are summed (316), the sum is filtered (318); the filtered sum is converted to the measurement of vehicle speed and a control signal for driving the vehicle speed display in response to the measurement is generated (320).

Abstract: An adaptive threshold circuit for use with a magnetic type of sensor that has a pick-up coil. The pick-up coil has an alternating voltage induced therein when a slot or tooth formed in a wheel rotates past the sensor. The circuit produces a square wave pulse voltage during positive half-cycles of the voltage generated in the pick-up coil. The circuit includes a digital to analog converter the input of which is connected to a selectable pulse counter. The pulse counter has a decrement function that allows for the count to be varied so as to accommodate sudden wheel decelerations. According to one embodiment, the counter may down count to reduce the count number. In accordance with a second embodiment, the counter may shift out one bit to perform a divide-by-two operation on the count number.

Abstract: A bicycle brake or derailleur cable including at least one signal transfer pathway, such as a pair of electrical conductors or a fiber optic. In one embodiment the cable structural members are electrically conductive and form at least one signal transfer pathway. Use of the cable with a cycle computer permits the wires between a wheel rotation sensor and the computer to be protected from damage and provides for an improved appearance.

Abstract: A detection and alarm circuit for protection of electronic components includes a fan motor current sensing resistor for producing a pulse that is amplified and introduced to a frequency-to-voltage converter for generating a filtered and processed voltage level for application to a voltage comparator. A reference voltage circuit supplies a voltage level to the comparator for matching with the filtered and processed voltage level and depending on the mismatch, an output signal is introduced to a transistor switch for operating an alert alarm device.

Abstract: Apparatus for determining the rotational speed of an AC induction motor based on a spectrum analysis of a magnetic flux signal. For a Phase I analysis, which is usually sufficient, three sets of families of peaks indicative of possible rotational speeds are defined, and the flux frequency spectrum is searched for peaks meeting the family definitions to determine candidate speeds, and to assign scores. If there is a candidate speed with an overall score which exceeds a predetermined threshold, the motor rotational speed is determined as that candidate speed. A Phase II analysis, employing a more exhaustive set of five additional family definitions, is applied when Phase I fails to reach a result.

Abstract: An object of the present invention is to provide an A/D conversion device capable of compensating for quantizing errors occurring as a result of variations in operating conditions and a physical quantity detection device using this A/D conversion device.

Abstract: A speed signal conditioning and test circuit includes a comparator which is connected to a digital input port of a microprocessor and which switches its output in response to the alternating current generated by the sensor when sensing wheel speed. A test sequence is initiated by injecting a signal into a tuned circuit formed by the inductance of the sensor coil, the filtering capacitors, and associated circuit resistances. The voltage output of the tuned circuit increases exponentially and switches the comparator to provide a test pulse of a predetermined time period. The microprocessor times the pulse to establish that an operative sensor is present. Since the inductance of the coil is switched out of the circuit in the case of an open or shorted sensor coil, no pulse is generated and the microprocessor accordingly determines that a defective sensor is present.

Abstract: A battery-powered rotation detector detects passing of a rotating magnet attached to a vehicle wheel to generate and transmit a rotation signal. A receiver receives the rotation signal. A processor computes the vehicle running condition (e.g., speed, traveled distance) from the received rotation signal and displays the results on a display device. The processor monitors intervals between the rotation signals to detect when the vehicle is stopped. When the vehicle is stopped, the processor disconnects a battery power supply from components such as the display device for power savings. In addition, the processor checks the strength of the received rotation signal to determine a capacity of the battery in the rotation detector, and operatively indicates a power failure of the rotation detector.

Abstract: A wheel speed sensor input circuit with sensor status detection having a comparator with a first input and a second input where both the first and second inputs are connected to a wheel speed sensor having electrical resistance where, when the status of the wheel speed sensor is to be ascertained, the second input is connected to ground through a diode using a switching transistor and the output of the comparator is driven high or low depending on the speed sensor electrical resistance where the output is high if the speed sensor is operational.

Abstract: A conversion circuit is provided for converting a differential voltage to a single-ended voltage. The conversion circuit has an input circuit including first and second input lines for receiving a differential voltage that is produced by a magnetic sensor in response to rotation of a wheel. First and second buffers are coupled to the first and second input lines, respectively, of the input circuit and each provide a buffered output. The conversion circuit further includes a difference amplifier having a positive input coupled to the output of the first buffer and a negative input coupled to the output of the second buffer. The amplifier provides as an output the voltage difference between the first and second inputs as a single-ended voltage output. The output circuit further converts the single-ended voltage output into a series of voltage pulses which provide rotational speed information about the wheel.

Abstract: Apparatus is presented for controlling the duty cycle of a pulse generator which provides a periodic input signal having a frequency proportional to the rate of movement of an input member. The input signal is compared with a threshold signal and, for each cycle of the periodic signal, an ON signal is provided so long as the magnitude of the input signal exceeds that of the threshold signal. The apparatus for controlling the duty cycle includes a clock source for providing clock pulses having a fixed frequency rate. A first counter counts the total number of clock pulses occurring during an interval corresponding with N of the ON pulses to provide a total count of B. A second counter counts the total number of clock pulses occurring during each of the N ON pulses and provide a total count of A. The ratio of A to B is calculated to provide a ratio R.

Abstract: A geartooth sensor is provided with a circuit which determined a threshold magnitude as a function of the minimum value of a first output signal from a magnetically sensitive component and an average output signal from a magnetic sensitive component. Circuitry is provided to determine the average signal. The minimum signal is then subtracted from the average signal and the resulting signal is doubled before being scaled by a predetermined fraction and then compared to the original output signal from the magnetically sensitive component. This circuit therefore determines a threshold signal as a function of both the minimum signal value and the average signal value and, in addition, enables the resulting signal to be scaled to a predetermined percentage of this difference for the purpose of selecting a threshold value that is most particularly suitable for a given application.

Abstract: A system for anti-lock brake and traction control has a control circuit comprising a microprocessor on a silicon die. Inputs from several variable reluctance wheel speed sensors are multiplexed to a single channel on the same die for signal processing including diagnostics, A/D conversion, square wave generation for each sensor by a state machine, end wheel speed determination from the square waves. The state machine algorithm tracks signal peaks and valleys and uses a dual hysteresis method of generating output transitions to capture all cycles of a signal having single cycle anomalies while rejecting noise. A single rear wheel sensor having twice the frequency of front wheel sensors for equal wheel speeds is processed twice as often as each front sensor. The diagnostics include detecting sensor and harness short and open circuits by comparison of signals to programmable thresholds and fault timing and latching by gauging open and short signals against programmable time limits.

Abstract: A magnetic field alternation detecting apparatus includes a magnetic member sensor enclosed in a case and having a core (i.e., a yoke) to which a magnet is attached and around which a coil is wound. The magnetic member sensor obtains as an electromotive voltage a change in magnetic flux linking the coil on the basis of a magnetic field distribution disturbed by an approaching magnetic member present near the case from a pair of output terminals of the coil. An analog-to-digital converter is connected to the output terminals of the coil using at least one control terminal of a transistor such as a bipolar transistor or an enhancement operation field effect transistor. A main current terminal of the transistor is connected to a pair of output terminals.

Abstract: In accordance with the teachings of the present invention, an adaptive threshold circuit is provided which develops a series of square-wave voltage pulses from an alternating differential voltage that is produced in response to the rotation of a wheel. The adaptive threshold circuit includes an input circuit for providing an input voltage in response to the alternating differential voltage. A first voltage comparator compares the input voltage with an adaptive analog threshold voltage and produces an output in response thereto which causes a rising edge of the square-wave voltage pulse. A second voltage comparator compares a selected portion of the input voltage with the adaptive analog threshold voltage and produces an output in response thereto. The adaptive threshold circuit further includes a binary counter having a reset input for receiving the first voltage comparator output and an enable input for receiving the second voltage comparator output and provides a plurality of binary outputs.

Abstract: An adaptive threshold circuit for use with a magnetic type of sensor that has a pick-up coil. The pick-up coil has an alternating voltage induced therein when a slot formed in a wheel rotates past the sensor. The circuit produces a square wave pulse voltage during positive half-cycles of the voltage generated in the pick-up coil. The circuit includes a digital to analog converter the input of which is connected to a pulse counter. The output of the converter is a function of the count magnitude in the counter and provides a variable threshold voltage that is compared by a voltage comparator with a voltage that is a function of the magnitude of the voltage generated in the pick-up coil. The circuit has an input circuit connected to the pick-up coil that includes a voltage attenuating circuit and a diode.

Abstract: Apparatus and method for detecting rotation of a shaft include a first antenna for transmitting electromagnetic energy into the shaft, a second antenna disposed for rotation with the shaft for modulating electromagnetic energy passing through the shaft in relation to the shaft rotational speed, and a detector for detecting the modulated electromagnetic energy that passes through the shaft.

Abstract: A speed and/or distance transducer is mounted in a bolt-shaped hollow housing and is threaded into a transmission and locked in place with its detector and adjacent a toothed wheel which rotates to produce an electrical output. An indicia is provided on the head of the bolt to allow proper spacing of the end of the transducer relative to the toothed wheel. A divider converts the output of the detector and a switch with a rotary member can be accessed through a bolt opening to allow the divider ratio to be changed. A plug covers the opening after the dividing ratio has been selected.

Abstract: A circuit configuration which serves to condition the output signal of a rotational speed sensor, e.g., the wheel sensor of an automotive vehicle. The circuit configuration includes a trigger circuit, the "hysteresis" or trigger thresholds thereof being controllable, and includes circuits for determining a coupling factor which, multiplied by the frequency of the sensor signal corresponding to the speed of rotation, forms the amplitude of the sensor output signal. To determine the coupling factor, and to adjust the hysteresis, threshold values are predefined for the output signal of the rotational speed sensor. Upon start of the vehicle, the coupling factor is determined from the frequency of the sensor signal at the point of time the threshold values are reached, and the hysteresis is adjusted accordingly.

Abstract: An adaptive loading circuit is provided for adaptively attenuating an alternating differential voltage that is produced by a magnetic sensor in response to the rotation of a wheel while maintaining noise immunity. The circuit includes an input for receiving an input differential voltage from the magnetic sensor via first and second input lines. A resistive divider network is included which has a resistive load serially connected to each of the first and second input lines and a plurality of adaptively selectable parallel resistive loads connected between the first and second input lines. Combinations of the parallel resistive loads are adaptively selected when the input differential voltage exceeds predetermined voltage thresholds so as to divide the input differential voltage into a selected portion thereof as an output differential voltage. In addition, the parallel resistive loads may be selectively switched out when the input differential voltage drops below a low voltage threshold.

Abstract: There is disclosed a meter driving device which can perform a smooth indication through a simple process in response to an input pulse even if the frequency of the input pulse is relatively low.An edge detector generates a one-shot pulse each time the edge of an input pulse is detected by the edge detector. CPU performs a digital filtering process to the one-shot pulse in response to a start signal having a constant update cycle that is provided from a timer. Thus, the high-frequency components are removed from the one-shot pulse so that a DC component is taken out to provide an angular shift .theta. of an indicating arm corresponding to the frequency of the input pulse. This DC component is used to move the indicating arm through a indicator drive device.

Abstract: A device for sensing the rotation speed of a bearing comprises an encoder member fastened to a rotating part of the bearing and a sensor assembly comprising a plastics material sensor support housing a sensor and a metal support for locating and fastening the sensor assembly on and to a non-rotating part of the bearing. The sensor support is overmolded onto the latter's outside surface. The sensor faces the encoder member in order to measure its rotation speed. The-metal support comprises a substantially axial centring portion adapted to cooperate removably with a bearing surface on the non-rotating part of the bearing and a washer-like plane radial portion adjacent the centring portion adapted to be clamped between a radial surface of the non-rotating part of the bearing and a radial surface of a non-rotating member. The device may be fitted to vehicle wheel hub assemblies.

Abstract: An air gap detector for use in antilocking brake systems includes an active integrator that integrates an output signal from a wheel speed sensor, that depends in part on the relative spacing between the wheel axle and its associated bearing, to thereby produce a signal that is inversely proportional to the air gap between the axle and bearing. The integrated signal is processed by peak detecting means to produce a peak signal that is proportional to the size of the air gap. The peak signal is then amplified and adjusted to produce a D.C. signal that is proportional to the size of the air gap.

Abstract: A road wheel speed sensor for use with an automotive vehicle supported on road wheels. A pulsating variation in magnetic flux is produced with rotation of one of the road wheels. A signal converter is provided for converting the pulsation magnetic flux variation into a rectangular pulse signal to switching a transistor on and off. The signal converter is connected through power and signal lines to a processor. The transistor has a base electrode for receipt of the rectangular pulse signal, an emitter electrode, and a collector electrode connected to the signal line. A first resistor is connected between the power line and the signal line. A second resistor is connected between the power line and the emitter electrode of the transistor. A third resistor is connected between the signal line and the ground. The processor calculates a speed of rotation of the road wheel in response to a voltage developed across the third resistor.

Abstract: An indicating system for measuring movement of a material, having a magnetic pickup device, waveform conditioning circuit and light signal emitter functioning under the system's own self-made power, having a light waveguide or optic fiber connecting the light signal emitter to a light signal receiver which in turn is connected to a signal processor for outputting information such as speed, acceleration and/or position of the material.

Abstract: A measuring circuit with a simple circuit configuration is capable of correcting dispersion of a characteristic of a display apparatus and of displaying the measurement result. The measuring circuit comprises an edge detecting circuit, for outputting an edge detection signal synchronous with clock pulses by performing sampling on an input signal, the sampling being performed using clock pulses having a frequency higher than a frequency of the input signal, a gate circuit outputting a first factor when receiving the edge detection signal from the edge detection circuit, a digital integrating filter circuit for outputting a signal having digital values converging to values corresponding to the frequency of the input signal by timing sampling operation based on cycles of the clock pulses.

Abstract: A method and apparatus for improving the speed of response and display accuracy of a periodic input signal, of the type having a widely variable frequency, on an analog gauge have a meter deflection representative of the frequency of the input signal. Frequency scaling means are provided for multiplying the frequency of the input signal by a first constant to generate an intermediate signal. Counting means are coupled to the frequency scaling means for counting the frequency of the intermediate signal for a time period which is directly proportional to the maximum sweep deflection arc of the gauge times a second constant, and is inversely proportional to the maximum expected frequency of the input signal. Meter driver means coupled to the counting means are provided for deflecting the meter proportional to the counted intermediate signal frequency.

Abstract: An air core gauge method and apparatus are disclosed. The apparatus receives an input signal and comprises a gauge device and driver circuit for driving the gauge device. A detection circuit detects transitions in the input signal and provides a control output in response to detected transitions. A power control circuit, responsive to the control output, provides a 100% duty cycle power signal to the driver circuit during detected transitions and otherwise provides a power signal with a duty cycle less than 100% to the driver circuit so that the average power consumed by the gauge is reduced and the operating temperature of the gauge is reduced.

Abstract: In one aspect of the present invention, an apparatus determines the rotational speed and direction of a rotating object. The apparatus includes a sensor adapted to detect the speed and direction of the rotating object and responsively produce a frequency signal indicative of the speed of the rotating object and a direction signal having a voltage value indicative of the rotational direction of the rotating object. A distinguishing stage receives the frequency and direction signals, and determines the voltage value of the portion of the direction signal that coincides with the falling edge of the frequency signal. Responsively the distinguishing stage produces a control signal having a voltage level responsive to the determined voltage value of the direction signal. A converting stage receives the frequency signal and responsively produces an output signal having a DC voltage proportional to the frequency of the frequency signal.

Abstract: Torsional oscillations of the drillstring will lead to frequency modulation (FM) of the signal from a vibratory source (e.g., the bit). This results, in the frequency domain, in sidebands being present around a detected excitation frequency. In accordance with the present invention, it has been discovered that these sidebands may be used in advantageous methods for optimizing drillstring and drilling performance. In a first embodiment of this invention, these sidebands are used to discriminate between downhole and surface vibrational sources. Once the location of the drillstring vibration is determined, appropriate action may be taken to optimize drilling and drillstring performance. In a second embodiment of this invention, the sidebands are used to determine the rotary speed of BHA (bottom hole assembly) components.

Abstract: A meter driving system measures a period of input signals, and operates meters based on the measured period data. When no period data arrive in a preset period of time after the last period data, the lapsed time is treated as the period data so as to renew the meter indication. The meter driving system is very responsive to a signal whose frequency is gradually decreased, thereby giving the indication with little delay.

Abstract: A driving apparatus used for an analog indicating instrument having a pair of cross coils comprises a pulse signal generating device for generating a pulse signal having a frequency proportional to a quantity to be measured, a frequency-voltage conversion device for generating a ripple voltage proportional to the frequency of the pulse, holding a mean voltage of the ripple voltage as an analog voltage while restraining the ripple, and controlling the analog voltage so as to change following a mean value of the ripple voltage, thereby to supply the analog voltage, and driving devices for supplying a current in accordance with the analog voltage to the cross coils so as to drive these cross coils. The driving apparatus has effects on improving responsibility of frequency-voltage conversion operation in a low frequency region and reducing the deflection of a pointer of an instrument by restraining the ripples.

Abstract: A frequency-to-voltage converter comprises a pulse generator, an integrator, an inverting amplifier, and a superimposing circuit. The pulse generator generates a pulse signal having a predetermined width. The integrator integrates and outputs the pulse signal. The inverting amplifier reverses the ripple component of the output of the integrator, outputting the reversed ripple component. The superimposing circuit superimposes the reversed ripple component on the output of the integrator. An automobile meter according to this invention comprises a frequency-to-voltage converter, a plurality of driving signal generators, and a plurality of pointer driving coils. The drive signal generators generate driving signals having values according to the output value of the integrator, applying the drive signals to pointer driving coils.