The present disclosure provides a primary frequency modulation method for a wind turbine, which may include: detecting a current frequency of a power grid; determining an instruction value of a power change amount for a primary frequency modulation by a first determining process when the current frequency of the power grid is less than a standard frequency of the power grid, wherein the first determining process may include: determining a reference value of the power change amount for the primary frequency modulation based on the current frequency; and when it is determined that currently there is an active power headroom for the wind turbine, comparing the reference value with a current active power headroom value of the wind turbine and determining the instruction value of the power change amount for the primary frequency modulation; and performing the primary frequency modulation based on the instruction value of the power change amount.

Improved determination of a trigger time. For this purpose, an input signal is provided to multiple low pass filters having different bandwidths. A trigger event is detected in each of the low pass filtered signals and a corresponding trigger time is determined. The trigger time which is determined based on valid trigger detection and provided by the low pass filter with the highest bandwidth is used for further analysis.

A waveform generation identification method includes: comparing individual waveform data obtained by a plurality of sensors, with at least one piece of characteristic waveform information; determining appearance probability of characteristic waveform information in at least a certain section of the waveform data, based on a degree of correlation between a peak section of the waveform data and the characteristic waveform information; and identifying a time when a section matching with the characteristic waveform information appears and a concerned sensor, based on the appearance probability.

There are provided a method, a system and a device for calibrating a frequency of a driving voltage waveform for a linear resonance device. An actual sampling frequency is continuously corrected, so that a difference between a measured natural frequency of the linear resonance device obtained during a calibration process and a frequency of a standard driving voltage waveform stored in a driving chip for the linear resonance device is in a predetermined range. The driving chip outputs a driving waveform at a finally corrected actual sampling frequency, to drive the linear resonance device. Further, only an actual sampling frequency is required to be adjusted, and it is not required to modify waveform data stored in the driving chip for the linear resonance device.

A method of setting a measurement instrument comprises the steps of: Providing a reference measurement instrument that uses at least one instrument parameter; Performing a training phase for a particular signal type to be processed by said reference measurement instrument in order to retrieve an optimal setting for said at least one instrument parameter; and Creating a lookup table for said particular signal type, said lookup table comprising at least said optimal setting for said at least one instrument parameter.

Further, a system for setting a measurement instrument is described.

A frequency ratio measurement device includes a counter section configured to count a time event of a first signal and output a count value obtained by multiplying the time event by k.sub.0, a time to digital converter section configured to output a time digital value corresponding to a phase difference between the first signal and a second signal, a combiner section configured to output a combined value of the count value and the time digital value, a subtractor section configured to output a difference value between a first value based on the combined value and a second value, a quantizer section configured to compare a third value based on the difference value with a predetermined threshold to thereby output a quantized value obtained by quantizing the third value, and a feedback section configured to output, based on a time event of the second signal, the second value based on the quantized value. The frequency ratio measurement device outputs, based on the quantized value, a delta-sigma modulated signal corresponding to a frequency ratio of the first signal and the second signal.

An oscillatory electric signal having an oscillation frequency is processed by time-sampling to generate a sampled oscillatory electric signal. A nonlinear circuit driven by the sampled oscillatory electric signal outputs a hysteretic response signal as a function of the sampled oscillatory electric signal. The hysteretic response signal has a frequency in a first frequency range as a result of an increase in the oscillation frequency of the oscillatory electric signal, and a frequency in a second frequency range as a result of a decrease in the oscillation frequency of the oscillatory electric signal. A detection circuit processes the hysteretic response signal to compute an envelope signal of the hysteretic response signal, perform a comparison of the envelope signal with a threshold, and produce a signal indicative of an increase or a decrease in the oscillation frequency of the oscillatory electric signal as a result of the outcome of the comparison.

Systems, methods, and apparatuses for magnetic field sensors with self-test include a detection circuit to detect speed and direction of a target. One or more circuits to test accuracy of the detected speed and direction may be included. One or more circuits to test accuracy of an oscillator may also be included. One or more circuits to test the accuracy of an analog-to-digital converter may also be included. Additionally, one or more IDDQ and/or built-in-self test (BIST) circuits may be included.

A sensor processing system includes a plurality of reduction circuits. The plurality of reduction circuits correspond to a plurality of sensors on a one-to-one basis. Each of the plurality of reduction circuits is electrically connected to an output terminal of a corresponding one of the plurality of sensors to reduce a low-frequency component of a sensor output of the corresponding one of the plurality of sensors.

Systems, methods, and apparatuses for magnetic field sensors with self-test include a detection circuit to detect speed and direction of a target. One or more circuits to test accuracy of the detected speed and direction may be included. One or more circuits to test accuracy of an oscillator may also be included. One or more circuits to test the accuracy of an analog-to-digital converter may also be included. Additionally, one or more IDDQ and/or built-in-self test (BIST) circuits may be included.