A method and apparatus for measuring a motor speed in which a measurement pulse train is formed from a measurement signal generated in a frequency generator coupled to the rotation of a motor, and a reference pulse train is formed with a frequency greater than that of the measurement pulse train, and the number of both pulses are counted for a predetermined sampling time, and both count values are compared, thereby measuring the motor speed. Accordingly, the rotation speed can be measured by a single algorithm regardless of the variation of the motor speed, and the measurement time and the measurement error can be greatly decreased. Furthermore, the continuous speed controlling over the whole speed range is possible.
In an engine-controlling rpm calculating apparatus, there are provided a rotary sensor for producing a detection pulse in response to an rpm related to the engine, and a microcomputer for calculating the rpm based upon the detection pulse so as to control the engine. The detection pulse contains a plurality of pulse series, and the microcomputer selects one pulse series from the plurality of pulse series in response to a drive region of the engine, and calculates the rpm related to the engine based upon both a detection time instant and the pulse number of the selected pulse series. As a result, the calculable high rpm region is expanded without changing the calculation time period, while the calculation capability of this rpm calculating apparatus with respect to the low rpm region is not deteriorated.
A system and method for calculating the speed of a moving member having an output device providing an output periodic signal as a function of displacement of the moving member includes measuring a time duration for a plurality of first periodic occurrences of the output periodic signal to occur. A number of second periodic occurrences of the output periodic signal is also counted in a selected time period. A speed of the moving member is calculated as a function of the time duration for the plurality of first periodic occurrences to occur and the number of second periodic occurrences to occur in the selected time period.
A method of measuring the period of a vehicle speed signal is disclosed that includes the steps of accumulating predetermined time interval increments between first and second rising edges of the signal, calculating a remainder time interval upon detection of the second edge of the signal and adding the remainder to the accumulated increments value to obtain the period, and calculating an average period from a plurality of consecutive period measurements. If the accumulated value exceeds a predetermined maximum value before the second edge occurs, the maximum value is used in calculating the average.
An electronic circuit having control data registers (24-28) for receiving the output of a digital counter (20) that records clock pulses within a measured time that is determined by a rotary speed sensor (14) which produces a square wave pulse train signal and separate registers (30,32) for recording the time of each signal developed by the speed sensor and the time to produce a pulse train signal of predetermined length whereby the data in the data registers may be used to determine velocity and derivatives of that velocity for use in solving dynamic equations stored in memory thus effecting control system output functions.
