42results about How to "Wide measurement frequency range" patented technology

The invention discloses a synchronous multi-frequency impedance measurement method which can overcome the shortcoming that the prior art can only measure single-frequency impedance at any moment and can achieve synchronous measurement of the multi-frequency impedance. The synchronous multi-frequency impedance measurement method provides a synchronous multi-frequency impedance measurement device to achieve a plurality of different frequencies and simultaneously effect on a sample to be tested, the impedance at different frequencies can be separately measured simultaneously, and further purposes of synchronous effecting and synchronous measuring are achieved.

The invention discloses a vibration sensor of a three-component fiber grating. The vibration sensor of the three-component fiber grating comprises a base, an outer shell, a fiber grating, an oscillator, an oscillator clamping seat, springs, and the like. Three same vibration sensors are mutually perpendicularly fixed on the base of a sensor. The outer shell of the sensor comprises two parts, the body part of the outer shell of the sensor is a box structure, five surfaces of the box structure are closed, an opening is arranged on one surface of the box structure, and the other part of the outer shell of the sensor is a sliding cover which covers the opening of the box structure. A circular hole is arranged at the top end of the outer shell, and transmission optical fibers and a sleeve pipe penetrate through the circular hole. A stainless steel cylinder is arranged inside the outer shell, the fiber grating which is coated with elastic materials is arranged inside the stainless steel cylinder, the lower end of the fiber grating is connected with the oscillator, the oscillator is arranged inside the oscillator clamping seat, and the lower end of the oscillator is connected with the bottom end of the outer shell of the sensor through a second spring. A grating is not required to be pasted on a mechanical structure so that restriction on natural frequency of the mechanical structure is effectively avoided and range of measuring frequency of the sensor is largely broadened. The vibration sensor of the three-component fiber grating is capable of measuring vibration amplitude, frequency and accelerated speed which are mutually perpendicular in three directions in real time, and preventing effectively over range damage of the sensor.

A power semiconductor module integrating a Hall current sensor, comprising an output electrode, a sampling control terminal, a bottom plate, a ceramic substrate, and a casing, the output electrode is connected to an output electrode arm arranged parallel to the direction of the bottom plate, and the output electrode arm is connected to the ceramic The substrates are connected, the output electrode arm is covered with a sensor core, the sensor core has an upward core opening, and a Hall element with pins facing upward is inserted into the core opening; the shell An insertion hole is provided at a corresponding position above the opening of the magnetic core, and pins of the Hall element pass through the insertion hole. The invention integrates the current sensor inside the power semiconductor module, increases the integration degree, miniaturization degree and stability of the control system, and reduces the subsequent use cost.

The invention provides a method and device for on-line sub / supersynchronous oscillation monitoring. First, interpolation processing is performed on the acquired three-phase current signals; then the amplitudes of the interpolated currents in each frequency band are calculated; finally, based on the amplitudes, the sub / The supersynchronous oscillation is monitored, and the sub / supersynchronous oscillation online monitoring process takes a short time, has strong real-time performance, and has high frequency resolution. The technical solution provided by the invention has a wide range of measurement frequency bands, and the current setting value and the sub / super synchronous oscillation current total content percentage setting value can be flexibly set for different application scenarios, and can provide guidance and reference for the monitoring of the dispatching master station. Provide support for targeted analysis and control.

The invention relates to a GaAs single quantum well-based THz detector implementation method. A GaAs detector comprises a GaAs single quantum well sample. A zig-zag-shaped hall strip is covered onto the upper surface of the GaAs single quantum well sample. The upper part of the left end of the hall strip and the lower part of the left end of the hall strip are respectively provided with a metal electrode 1 and a metal electrode 3. The upper part of the right end of the hall strip and the lower part of the right end of the hall strip are respectively provided with a metal electrode 2 and a metal electrode 4. According to the technical scheme of the invention, an incident Terahertz signal is converted into a voltage signal. The method belongs to the technical field of the direct detection technology. Meanwhile, the detector is high in frequency resolution property and high in sensitivity.