An assembly has a rotating element, a sensor, and an evaluation unit; wherein the element has a number a of markings; wherein the markings pass through a region detected by the sensor in cycles when the element rotates; wherein the sensor is configured to send a signal to the evaluation unit; and wherein the evaluation unit is configured to assign a time t.sub.i for when each signal is sent, wherein the evaluation unit is configured to calculate a function m(t) over time t as a measure for a gradient of the rotational rate of the element.

An example non-transitory machine-readable storage medium includes instructions to determine whether a cooling fan is controlled by pulse wave modulation (PWM) or is voltage-controlled. When executed, the instructions cause a processor of a computing device to transmit first and second PWM test signals at different PWM duties to a fan connector connected to the cooling fan, receive a first and second fan speed signals in response, and determine, when the first fan speed signal is not equal to the second fan speed signal, that the cooling fan is a PWM-controlled fan. The instructions further cause the processor to transmit first and second voltage test signals at different voltages to the fan connector, receive a third fan and fourth speed signal in response, and determine, when the third fan speed signal is not equal to the fourth fan speed signal, that the cooling fan is a voltage-controlled fan.

An example non-transitory machine-readable storage medium includes instructions to determine whether a cooling fan is controlled by pulse wave modulation (PWM) or is voltage-controlled. When executed, the instructions cause a processor of a computing device to transmit first and second PWM test signals at different PWM duties to a fan connector connected to the cooling fan, receive a first and second fan speed signals in response, and determine, when the first fan speed signal is not equal to the second fan speed signal, that the cooling fan is a PWM-controlled fan. The instructions further cause the processor to transmit first and second voltage test signals at different voltages to the fan connector, receive a third fan and fourth speed signal in response, and determine, when the third fan speed signal is not equal to the fourth fan speed signal, that the cooling fan is a voltage-controlled fan.

A method for estimating the speed of a motor vehicle includes defining a first speed threshold that corresponds to a minimum speed value supplied by a vehicle wheel angular speed sensor, defining a second speed threshold that is greater than the first, estimating low speed values when the vehicle is running below the first speed threshold by using an estimation method of adaptive filtered type, measuring high speed values when the vehicle is running above the second speed threshold by using vehicle speed values supplied by the wheel angular speed sensor, and in the intermediate zone between the first and second speed thresholds, mixing high speed with low speed.

A method for measuring rotation speed of an aircraft engine shaft includes: acquisition of an alternating rotation speed detection signal across terminals of a phonic wheel sensor, conversion of the alternating signal into a square signal; comparison of a plurality of previously-stored square signal period samples to lower and upper period limits, to determine valid samples of a value included between the terminals; if the number of valid samples is greater than a first threshold, determination on the basis of the valid samples of a desired period of the square signal; and at least on the condition that the number of valid samples is less than the first threshold, computation of a plurality of sums of samples, and computation of the average of a set comprising a number of valid period samples and a number of sums from among the plurality of sums of at least two samples.

A method for measuring rotation speed of an aircraft engine shaft includes: acquisition of an alternating rotation speed detection signal across terminals of a phonic wheel sensor, conversion of the alternating signal into a square signal; comparison of a plurality of previously-stored square signal period samples to lower and upper period limits, to determine valid samples of a value included between the terminals; if the number of valid samples is greater than a first threshold, determination on the basis of the valid samples of a desired period of the square signal; and at least on the condition that the number of valid samples is less than the first threshold, computation of a plurality of sums of samples, and computation of the average of a set comprising a number of valid period samples and a number of sums from among the plurality of sums of at least two samples.

A sensor system can include a sensor configured to output a sensor signal having a waveform output with noise and a peak detector module configured to receive the waveform output from the sensor and to detect a peak amplitude of the waveform output. The peak detector module can be configured to output a peak amplitude signal. The system can include a threshold module configured to receive the peak amplitude signal and to calculate a cutoff threshold based on the peak amplitude signal. The threshold module can be configured to output a cutoff threshold signal. The system can include a comparator operatively connected to the sensor and the threshold module. The comparator can be configured to receive the sensor signal and the cutoff threshold signal to compare the sensor signal and the cutoff signal. The comparator can be configured to output a high signal or a low signal based on the comparison of the sensor signal and the cutoff threshold signal which changes as a function of the peak amplitude of the sensor signal.

An encoder includes a code disc and a processor communicatively coupled with the code disc. The code disc is configured to rotate along with a rotating object and includes a plurality of fan teeth extending radially. One of the plurality of fan teeth is different from other ones of the plurality of fan teeth, and the other ones of the fan teeth are same to each other. A first portion of a detection signal that is generated in one rotation of the code disc, corresponding to the one of the plurality of fan teeth, is different from a second portion of the detection signal, corresponding to each of the other ones of the fan teeth. The processor is configured to detect the rotation of the code disc to obtain the detection signal and a rotation parameter of the rotating object based on the detection signal.

A monitoring system for monitoring one or more properties associated with a rotating shaft is provided. The system includes a first phonic wheel which is mounted coaxially to the shaft for rotation therewith, the first phonic wheel comprising a circumferential row of teeth. The system further includes a first sensor configured to detect the passage of the row of teeth of the first phonic wheel by generating a first alternating measurement signal. The system further includes a processor unit configured to determine the durations of successive first speed samples. Each first speed sample is a block of n successive cycles of the first alternating measurement signal, where n is an integer, and in which the beginning of each cycle is a zero-crossing point from the previous cycle and the end of each cycle is the corresponding zero-crossing point to the next cycle. At least one axial location of the first phonic wheel every m.sup.th tooth of the row of teeth of the first phonic wheel has a circumferential thickness which is different from that of the other teeth of the first phonic wheel, where m is an integer, m≠n, and m is neither a factor nor a multiple of n. When the first sensor is positioned at said axial location of the first phonic wheel and at any given rotational speed of the first phonic wheel, the durations of the successive first speed samples display a characteristic repeating pattern of longer and shorter sample durations relative to the average duration of the successive first speed samples. The amount by which the longer and shorter sample durations differ from the average duration is in proportion to the amount by which the circumferential thickness of the m.sup.th teeth differs from that of the other teeth at said axial location of the first phonic wheel. The processor unit monitors the properties associated with the rotating shaft from the characteristic repeating pattern.

A control circuit is provided for a sensor that determines a sensed property. The control circuit includes an input interface configured to receive high-resolution data and low-resolution data for the sensed property. The control circuit further includes circuitry configured to determine information on a functional state of the sensor using the high-resolution data and the low-resolution data.