A frequency debugging board includes a bottom plate; a variable capacitor and a plurality of first probes that are all disposed on the bottom plate, two ends of the variable capacitor being each connected to a first probe; and a plurality of second probes and at least one switch that are all disposed on the bottom plate, any two adjacent second probes being connected to each other through a switch.

A frequency debugging board includes a bottom plate; a variable capacitor and a plurality of first probes that are all disposed on the bottom plate, two ends of the variable capacitor being each connected to a first probe; and a plurality of second probes and at least one switch that are all disposed on the bottom plate, any two adjacent second probes being connected to each other through a switch.

A method for detection of a sub-synchronous oscillation in a power system includes measuring a three-phase measurement signal of an electric system value, analyzing the measurement signal to detect an oscillation component of the measurement signal having an oscillation frequency lower than a system frequency of the power system, deciding whether the detected oscillation component at the oscillation frequency qualifies as a sub-synchronous oscillation, and disconnecting a generator from the power system that might be affected by the sub-synchronous oscillation. To detect sub-synchronous oscillations with low computational effort and good accuracy, an amplitude of each phase of the oscillation component is calculated and compared against a threshold, a sub-synchronous oscillation is detected upon exceeding the threshold during a given time delay, and a fault signal is generated upon detecting a sub-synchronous oscillation. A device having a processing unit is also provided.

A method for detection of a sub-synchronous oscillation in a power system includes measuring a three-phase measurement signal of an electric system value, analyzing the measurement signal to detect an oscillation component of the measurement signal having an oscillation frequency lower than a system frequency of the power system, deciding whether the detected oscillation component at the oscillation frequency qualifies as a sub-synchronous oscillation, and disconnecting a generator from the power system that might be affected by the sub-synchronous oscillation. To detect sub-synchronous oscillations with low computational effort and good accuracy, an amplitude of each phase of the oscillation component is calculated and compared against a threshold, a sub-synchronous oscillation is detected upon exceeding the threshold during a given time delay, and a fault signal is generated upon detecting a sub-synchronous oscillation. A device having a processing unit is also provided.

A measurement device measures a frequency response of a servo system, applies predetermined oscillation are associated with each other to the servo system, identifies, from a result of oscillation application, a pair of a first oscillation application signal and a first response signal, and identifies a pair of a second oscillation application signal and a second response signal. Then, a first frequency response that is a frequency response is calculated on the basis of the first oscillation application signal and the first response signal, a second frequency response that is a frequency response is calculated on the basis of the second oscillation application signal and the second response signal, and the first frequency response and the second frequency response are synthesized.

A measurement device measures a frequency response of a servo system, applies predetermined oscillation are associated with each other to the servo system, identifies, from a result of oscillation application, a pair of a first oscillation application signal and a first response signal, and identifies a pair of a second oscillation application signal and a second response signal. Then, a first frequency response that is a frequency response is calculated on the basis of the first oscillation application signal and the first response signal, a second frequency response that is a frequency response is calculated on the basis of the second oscillation application signal and the second response signal, and the first frequency response and the second frequency response are synthesized.

Provided are an ultrasonic transducer having a state monitoring function, and an ultrasonic cleaning device using the same. The ultrasonic transducer having a state monitoring function is a Langevin ultrasonic transducer for use in an ultrasonic cleaning device configured to clean an object to be cleaned via cleaning liquid to which ultrasonic vibrations are applied, the ultrasonic transducer having a state monitoring function including a plurality of piezoelectric elements, which are arranged to be stacked on each other, and are expandable and contractable in a direction of the stacking, a part of the plurality of piezoelectric elements serving as a vibration exciting piezoelectric element configured to expand and contract by being applied with an AC voltage, another part of the plurality of piezoelectric elements serving as a state monitoring piezoelectric element configured to output a state monitoring voltage by the expansion and contraction of the vibration exciting piezoelectric element.

Provided are an ultrasonic transducer having a state monitoring function, and an ultrasonic cleaning device using the same. The ultrasonic transducer having a state monitoring function is a Langevin ultrasonic transducer for use in an ultrasonic cleaning device configured to clean an object to be cleaned via cleaning liquid to which ultrasonic vibrations are applied, the ultrasonic transducer having a state monitoring function including a plurality of piezoelectric elements, which are arranged to be stacked on each other, and are expandable and contractable in a direction of the stacking, a part of the plurality of piezoelectric elements serving as a vibration exciting piezoelectric element configured to expand and contract by being applied with an AC voltage, another part of the plurality of piezoelectric elements serving as a state monitoring piezoelectric element configured to output a state monitoring voltage by the expansion and contraction of the vibration exciting piezoelectric element.

Disclosed is a measurement system for analysing RF signals. The measurement system includes an optically transparent enclosure including an optically pumpable gas, and a printed circuit board, PCB including an electrical transmission line for guiding the RF signal to be analyzed through the enclosure and a reflective planar face. The measurement system includes an optical pump for emitting preferably coherent light onto the reflective planar face, and a detector for detecting an optical property of the emitted light being reflected by the reflective planar face. This provides a better laser/microwave overlap in atomic vapor quantum sensing setups, where it is crucial to overlap the regions with highest laser intensity and microwave field strength.

Disclosed is a measurement system for analysing RF signals. The measurement system includes an optically transparent enclosure including an optically pumpable gas, and a printed circuit board, PCB including an electrical transmission line for guiding the RF signal to be analyzed through the enclosure and a reflective planar face. The measurement system includes an optical pump for emitting preferably coherent light onto the reflective planar face, and a detector for detecting an optical property of the emitted light being reflected by the reflective planar face. This provides a better laser/microwave overlap in atomic vapor quantum sensing setups, where it is crucial to overlap the regions with highest laser intensity and microwave field strength.