A circuit includes a radio frequency (RF) channel including an input node and an output node and being configured to receive an RF oscillator signal at the input node and to provide an RF output signal at the output node; a mixer configured to mix an RF reference signal and an RF test signal representative of the RF output signal to generate a mixer output signal; an analog-to-digital converter configured to sample the mixer output signal in order to provide a sequence of sampled values; and a control circuit configured to provide a sequence of phase offsets by phase-shifting at least one of the RF test signal and the RF reference signal using one or more phase shifters, calculate a spectral value from the sequence of sampled values; and calculate estimated phase information indicating a phase of the RF output signal based on the spectral value.

A system for passive microwave remote sensing using at least one microwave radiometer includes a fixed body portion and a mobile body portion. The mobile body portion is configured for rotatably coupling with the fixed body portion for rotation about a rotation axis. The mobile body portion is configured for supporting the microwave radiometer therein such that the microwave radiometer rotates about the rotation axis when the mobile body portion is rotated about the rotation axis such that a polarization axis of the radiometer is aligned with an earth axis. The fixed body portion includes a motor mechanism for effecting rotation of the mobile body portion. In an embodiment, the mobile body portion includes a plurality of body section, each body section being configured for supporting a microwave radiometer therein. In another embodiment, each one of the plurality of body sections is configured to be interchangeably coupled with each other.

Provided a method including applying a Fourier Transform to an AC current waveform measured to perform conversion thereof to a frequency domain; adjusting entire phase components of frequency spectra obtained as a result of the Fourier Transform, such that a phase component of an AC power supply frequency becomes zero; and applying an inverse Fourier Transform to the frequency spectra with the entire phase components thereof adjusted to obtain a current waveform in a time domain.

An apparatus for generating an output signal having a waveform that is repeated every period, includes a storage configured to store values corresponding to the waveform in a portion of a period of the output signal, a counter configured to generate a first index of a sample included in the output signal, a controller configured to generate at least one control signal based on the first index and the period of the output signal, and a calculation circuit configured to generate the output signal by calculating an output from the storage based on the at least one control signal.

An apparatus for generating an output signal having a waveform that is repeated every period, includes a storage configured to store values corresponding to the waveform in a portion of a period of the output signal, a counter configured to generate a first index of a sample included in the output signal, a controller configured to generate at least one control signal based on the first index and the period of the output signal, and a calculation circuit configured to generate the output signal by calculating an output from the storage based on the at least one control signal.

A method includes performing by a processor: determining a phase angle alignment parameter based on a ratio of a phase angle difference and a frequency difference, the phase angle difference comprising a difference between a first phase angle corresponding to a reference synchronized measurement device (SMD) and a second phase angle corresponding to a follower SMD, the frequency difference comprising a difference between a frequency at which the first and second phase angles are measured and a nominal frequency; receiving a first plurality of synchrophasor measurements of a power system signal from the reference SMD; receiving a second plurality of synchrophasor measurements of the power system signal from the follower SMD, the first plurality of synchrophasor measurements and the second plurality of synchrophasor measurements being offset in time relative to each other by a sampling time shift; and aligning phase angles of the second plurality of synchrophasor measurements with phase angles of the first plurality of synchrophasor measurements using the phase angle alignment parameter.

A method includes performing by a processor: determining a phase angle alignment parameter based on a ratio of a phase angle difference and a frequency difference, the phase angle difference comprising a difference between a first phase angle corresponding to a reference synchronized measurement device (SMD) and a second phase angle corresponding to a follower SMD, the frequency difference comprising a difference between a frequency at which the first and second phase angles are measured and a nominal frequency; receiving a first plurality of synchrophasor measurements of a power system signal from the reference SMD; receiving a second plurality of synchrophasor measurements of the power system signal from the follower SMD, the first plurality of synchrophasor measurements and the second plurality of synchrophasor measurements being offset in time relative to each other by a sampling time shift; and aligning phase angles of the second plurality of synchrophasor measurements with phase angles of the first plurality of synchrophasor measurements using the phase angle alignment parameter.

A method and device for increasing an accuracy of a phase measurement, wherein the method includes: receiving a measurement signal; performing a frequency-domain transformation to the measurement signal to obtain a frequency-domain measurement sequence; determining phases that correspond to frequency-domain measurement signals, and determining a phase difference between the frequency-domain measurement signals that correspond to two neighboring specified frequency points; according to the phases, the phase difference and a window function, performing a sliding-window-type phase fitting to the frequency-domain measurement sequence, to obtain phase-fitting data that correspond to sliding windows; and according to the phase-fitting data of the sliding windows, determining phase-calibration data that correspond to the sliding windows, and, by using the phase-calibration data of the sliding windows, forming phase-calibration data within a specified frequency band. The method reduces an error of fitting, and increases an accuracy of a phase calibration.

A method and device for increasing an accuracy of a phase measurement, wherein the method includes: receiving a measurement signal; performing a frequency-domain transformation to the measurement signal to obtain a frequency-domain measurement sequence; determining phases that correspond to frequency-domain measurement signals, and determining a phase difference between the frequency-domain measurement signals that correspond to two neighboring specified frequency points; according to the phases, the phase difference and a window function, performing a sliding-window-type phase fitting to the frequency-domain measurement sequence, to obtain phase-fitting data that correspond to sliding windows; and according to the phase-fitting data of the sliding windows, determining phase-calibration data that correspond to the sliding windows, and, by using the phase-calibration data of the sliding windows, forming phase-calibration data within a specified frequency band. The method reduces an error of fitting, and increases an accuracy of a phase calibration.

A method for calibrating a phased array antenna is provided. The phased array antenna includes multiple transmission modules each including a phase shifter that changes a phase of a high frequency signal output from a signal source, an amplifier that amplifies an amplitude of the high frequency signal, and a transmission antenna that converts the high frequency signal into a radio wave, and a reception module including a reception antenna. The method includes a step of receiving, by the reception antenna, a reflected wave that is a radio wave transmitted from the transmission antenna of each of the multiple transmission modules and reflected outside the phased array antenna, and a step of adjusting the phase shifter and the amplifier of each of the multiple transmission modules based on an amplitude and a phase of the reflected wave received.