An environmental frequency sensing device, includes logic that performs signal strength (SS) level separation on a received band of frequencies to produce SS level separated frequencies. The logic performs frequency grouping on the SS level separated frequencies for each signal strength level to produce magnitude information for each grouping. The logic generates peak data by detecting peaks of the produced magnitude information. The logic generates an edge event indicating a signal edge based on arrival or departure of a given peak and compares, on a frequency basis, generated edges to stored fingerprint data of a signal of interest. Based on the comparison, the logic provides detected signal data indicating current use of a range of frequencies in an environment.

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.

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 method for phase-voltage based motor period measurement includes generating a commanded phase voltage and applying the commanded phase voltage to a first phase voltage input of an electric motor, a second phase voltage input of the electric motor, and a third phase voltage input of the electric motor, measuring a first period of a phase voltage associated with the first phase voltage input and the second phase voltage input and comparing the measured first period to a frequency of the commanded phase voltage, and, in response to a determination that the measured first period of the phase voltage associated with the first phase voltage input and the second phase voltage input is outside of a range of the frequency associated with the commanded phase voltage, identifying a fault associated with the first integrated circuit or signal path.

A MEMS device may output a signal during operation that may include an in-phase component and a quadrature component. An external signal having a phase that corresponds to the quadrature component may be applied to the MEMS device, such that the MEMS device outputs a signal having a modified in-phase component and a modified quadrature component. A phase error for the MEMS device may be determined based on the modified in-phase component and the modified quadrature component.

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 (BEST) circuits may be included.

A ballast type detecting circuit includes a ballast signal clamping circuit coupled to a ballast, wherein the ballast signal clamping unit is configured to clamp an output of the ballast, and a ballast type detection circuit configured to compare first and second reference clocks and the clamped output of the ballast to determine a type of the ballast, each of the first and second reference clocks having a frequency lower than an output frequency of a first type ballast and higher than an output frequency of a second type ballast. Thus, the ballast type detecting circuit detects a type of electronic ballast and magnetic ballast based on a digital output signal and decreases a number of outside circuit elements through a ballast type detection based on a digital output signal.

A harmonic distortion separation method, nonlinear character determination method, apparatus and system where a phase difference between an inherent harmonic and a generated harmonic is determined by using multiple groups of input power, output power and fundamental magnitudes of a memoryless nonlinear transfer function of a nonlinear model of a system to be measured, and power of a harmonic generated by the system to be measured is separated by using the phase difference. In an embodiment, the phase difference between the inherent harmonic and the generated harmonic is first determined by using an assumption that a model coefficient is a constant according to the set nonlinear model, then the harmonic separation is performed by using the phase difference, and the power of the harmonic generated by the system to be measured is calculated.

An RF phase offset detection system, which includes a first RF phase detector and a second RF phase detector, and measures a first phase offset between a first RF signal and a second RF signal, is disclosed. Each of the first RF signal and the second RF signal has a common RF frequency. The first RF phase detector detects and filters the first RF signal and the second RF signal to provide a first detection signal. The second RF phase detector receives and phase-shifts the second RF signal to provide a phase-shifted RF signal. The second RF phase detector further detects and filters the first RF signal and the phase-shifted RF signal to provide a second detection signal, such that a combination of the first detection signal and the second detection signal is representative of the first phase offset.

A method includes reading first and second timer count values from a timer. The first timer count value is associated with a first time point, and the second timer count value is associated with a second time point. Also, the method includes calculating a difference between the first and the second timer count values, and determining whether the difference is within a range. The range is based on a desired executing frequency to perform a computing task, a variation of the desired executing frequency, and a timer frequency. Further, based on the difference not being within the range, the method includes setting an error flag value to be true and incrementing an error count value.