A frequency measurement device includes a sampling unit that outputs a voltage sampling value in accordance with a voltage to be sampled and a sampling frequency; an single-cycle DFT angle shift computation unit that computes and outputs a first angle shift in accordance with the voltage sampling value; an multi-cycle DFT angle shift computation unit that computes and outputs a second angle shift in accordance with the voltage sampling value; a selection unit that selects and outputs one of the first and second angle shifts as a selected angle offset; a sampling frequency computation and outputting unit that computes a sampling frequency in accordance with the selected angle offset and outputs the same to the sampling module unit as a new sampling frequency; and a frequency measurement value computation and outputting unit that computes and outputs a frequency measurement value in accordance with the selected angle offset.

A battery diagnosis apparatus determines whether a battery may be reused and includes a data obtaining device configured to output a perturbation signal, a signal regulating device configured to generate a current by applying the perturbation signal to a battery and performing feedback of a current signal output from the battery, and a noise canceling device configured to cancel noises of the current signal and a voltage signal received from the battery. The data obtaining device outputs the perturbation signal while changing a frequency, obtains an impedance spectrum based on the noise-canceled current signal and voltage signal for each frequency, and determines whether to reuse the battery based on the obtained impedance spectrum.

High impedance fault (HIF) detection and location accuracy is provided. An HIF has random, irregular, and unsymmetrical characteristics, making such a fault difficult to detect in distribution grids via conventional relay measurements with relatively low resolution and accuracy. Embodiments disclosed herein provide a stochastic HIF monitoring and location scheme using high-resolution time-synchronized data in micro phasor measurement units (μ-PMUs) for distribution network protection. In particular, a fault detection and location process is systematically designed based on feature selections, semi-supervised learning (SSL), and probabilistic learning.

High impedance fault (HIF) detection and location accuracy is provided. An HIF has random, irregular, and unsymmetrical characteristics, making such a fault difficult to detect in distribution grids via conventional relay measurements with relatively low resolution and accuracy. Embodiments disclosed herein provide a stochastic HIF monitoring and location scheme using high-resolution time-synchronized data in micro phasor measurement units (μ-PMUs) for distribution network protection. In particular, a fault detection and location process is systematically designed based on feature selections, semi-supervised learning (SSL), and probabilistic learning.

The disclosure relates to a system and method for correcting inhomogeneity in an MRI image. The method may include the steps of: acquiring a first set of k-space data, acquiring a second set of k-space data, generating the convolution kernel of the first set of k-space data based on the first set of k-space data and the second set of k-space data, performing inverse Fourier transform on the convolution kernel of the first set of k-space data to obtain an inversely transformed convolution kernel of the first set of k-space data, and generating a corrector based on the inversely transformed convolution kernel of the first set of k-space data. The method may be implemented on a machine including at least one processor and storage.

The disclosure relates to a system and method for correcting inhomogeneity in an MRI image. The method may include the steps of: acquiring a first set of k-space data, acquiring a second set of k-space data, generating the convolution kernel of the first set of k-space data based on the first set of k-space data and the second set of k-space data, performing inverse Fourier transform on the convolution kernel of the first set of k-space data to obtain an inversely transformed convolution kernel of the first set of k-space data, and generating a corrector based on the inversely transformed convolution kernel of the first set of k-space data. The method may be implemented on a machine including at least one processor and storage.

Methods and systems in accordance with the present invention provide an RF spectrum analyzer on a computer chip, such as an integrated circuit. They may provide RF spectrum analyzer functions on a much smaller scale, which is easier to implement, transport and install in other equipment. They present a single chip solution that is smaller, lighter and more compact than conventional systems. Additionally, they may be put in hand held (or smaller) devices.

Methods and systems in accordance with the present invention provide an RF spectrum analyzer on a computer chip, such as an integrated circuit. They may provide RF spectrum analyzer functions on a much smaller scale, which is easier to implement, transport and install in other equipment. They present a single chip solution that is smaller, lighter and more compact than conventional systems. Additionally, they may be put in hand held (or smaller) devices.

An arc detector for a RF power supply system, where the RF power supply incudes a first RF power supply and a second RF power supply. A signal applied to a non-linear load varies in accordance with an output from one of the first RF power supply or the second RF power supply. The signal has a frequency. During an arc or arc condition in the non-linear load, the frequency of the signal changes, and if the frequency is outside of a selected range, an arc or arc condition is indicated. The frequency can be determined by digitizing the signal into a series of pulses and measuring a time or period between pulses.

An arc detector for a RF power supply system, where the RF power supply incudes a first RF power supply and a second RF power supply. A signal applied to a non-linear load varies in accordance with an output from one of the first RF power supply or the second RF power supply. The signal has a frequency. During an arc or arc condition in the non-linear load, the frequency of the signal changes, and if the frequency is outside of a selected range, an arc or arc condition is indicated. The frequency can be determined by digitizing the signal into a series of pulses and measuring a time or period between pulses.