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61 results about "Frequency standard" patented technology

A frequency standard is a stable oscillator used for frequency calibration or reference. A frequency standard generates a fundamental frequency with a high degree of accuracy and precision. Harmonics of this fundamental frequency are used to provide reference points.

Self-calibrating atomic wavemeter

The invention relates to a self-calibration atomic wavelength meter. The self-calibration atomic wavelength meter comprises a saturated absorption spectrum light path for locking a detection laser frequency on a cesium atom energy level transition line based on a saturated absorption spectrum; the double-peak spectrum light path scans the frequency of a coupled laser after the frequency of the detection laser is locked by a saturated absorption spectrum, and when the detection laser and the coupled laser jointly act on alkali metal atoms and are subjected to resonance excitation, an electromagnetic induced transparency effect is generated; when the detection laser is detuned, the detection laser and the combined laser jointly act on the alkali metal atoms to generate non-resonance excitation, a double-peak EIT spectrum with Doppler frequency shift is generated, and the wavelength measurement of the current detection laser can be completed based on the linear relation between the double-peak spectrum interval and the detuning amount of the detection laser. In addition, the double-peak spectrum interval is compared with the atomic energy level transition frequency, the difference between the double-peak spectrum interval and the atomic energy level transition frequency serves as an error signal to be fed back to the control end of the detection laser, the frequency of the detection laser is tuned to the reference frequency standard, and calibration of the wavemeter can be achieved.
Owner:NAT UNIV OF DEFENSE TECH

Frequency standard remote calibration method and system based on NTP protocol

The invention discloses a frequency standard remote calibration method and system based on an NTP protocol. The method comprises the following steps: S1, an NTP protocol server reads a first frequency standard signal meeting a precision requirement as a reference frequency signal and initializes local time; the calibration device reads a calibrated second frequency standard signal as a reference frequency signal, counts time according to a second frequency nominal value and completes initialization; s2, the calibration equipment performs message transmission with a server through an NTP protocol transceiving module, records transceiving timestamps, calculates clock skew and adjusts local time to complete synchronization; s3, the calibration device repeatedly transmits the message according to a preset period, calculates clock skew and network round-trip delay round by round, and obtains a multi-tuple sample; and S4, removing abnormal samples by network round-trip delay, performing linear fitting on reserved samples, and taking a negative value of a fitting slope as a relative frequency deviation of a second frequency standard. According to the invention, remote calibration of the frequency standard is carried out by using the NTP, and compared with satellite and optical fiber remote calibration technologies, the cost required by calibration can be greatly reduced.
Owner:ZHEJIANG INSTITUTE OF QUALITY SCIENCES

High-precision time-keeping low-phase-noise time synchronization equipment

The invention provides a high-precision time-keeping low-phase-noise time synchronization device, and belongs to the technical field of time synchronization. The system comprises a power supply module, a satellite time service module, a frequency source module, a clock synchronization module, a frequency shunt module, a communication interface module and a Bluetooth module. Wherein the power supply module adopts a dual-power-supply redundant circuit design, and after one power supply breaks down, the other power supply can be automatically switched; the satellite time service module adopts a single Beidou signal baseband signal processing algorithm and an anti-cheating design, so that the safety of equipment is improved; the frequency source module comprises a constant-temperature crystal oscillator and a rubidium atomic clock, and high-time-keeping and low-phase-noise signal output is achieved in the mode that the crystal oscillator and the atomic clock are complementary. According to the invention, the problem that the conventional time synchronization equipment cannot have high time keeping precision and low phase noise of output signals at the same time is solved, a high-steady-state low-phase-noise 10MHz frequency standard signal, a 1PPS time service signal and an NTP network time service signal can be provided, and time service is provided for various terminals or servers.
Owner:SHENZHEN YUANDONG HUAQIANG NAVIGATION & ORIENTATION CO LTD

Fast taming method and system based on high-stability OCXO

This invention belongs to the field of time-frequency unification and relates to a fast discipline method and system based on a high-stability OCXO. The method includes selecting a primary reference source, inputting the reference signal into a phase-locked loop frequency multiplier for frequency multiplication, and inputting the processed high-frequency reference signal into a high-precision phase measurement module. A monitoring and processing platform controls two frequency standard signals output from the OCXO frequency standard source through a control word. The first frequency standard signal of the first channel is input into a phase-locked loop frequency divider, and the second frequency standard signal is output to the high-precision phase measurement module. The third frequency standard signal of the second channel is directly input into the high-precision phase measurement module to measure the phase difference between the high-frequency reference signal and the second frequency standard signal. The monitoring and processing platform outputs an updated control word through a fast discipline algorithm to correct the OCXO frequency standard source parameters. The fast discipline process continues until the OCXO frequency standard source stabilizes and the phase difference with the reference source converges, ending the fast discipline state.
Owner:CETC CHIPS TECH GRP CO LTD

Full-range error on-line calibration device and calibration method for low-voltage current transformer

The application discloses a full-range error live calibration device and method for a low-voltage current transformer, comprising: a current control unit for outputting full-range calibration current control signals of each frequency; a hetero-frequency calibration current source for outputting full-range hetero-frequency current signals based on the current control signals and injecting the signals into the measured current transformer and a standard current transformer; an open current sensor for measuring a background current signal in real time; a signal decoupling unit for acquiring a mixed-frequency error voltage signal, eliminating a voltage component generated by the background current signal in the mixed-frequency error voltage signal, and acquiring a hetero-frequency error voltage signal; an error measurement unit for calculating ratio error and phase error of the measured current transformer based on the hetero-frequency standard signal and the hetero-frequency error voltage signal; and a data processing unit for determining calibration error under a power frequency frequency mapping based on the ratio error and the phase error under each hetero-frequency frequency.
Owner:CHINA ELECTRIC POWER RESEARCH INSTITUTE CO LTD +2

Multi-source heterogeneous clock group management system and method based on ALGOS time scale algorithm

The invention discloses a multi-source heterogeneous clock group management system and method based on an ALGOS time scale algorithm. The method comprises the steps that an atomic clock group outputs multiple paths of radio frequency analog signals; the signal frequency discrimination comparison module is used for converting the radio frequency analog signal into a digital signal, measuring the frequency and calculating frequency difference data; the atomic time scale calculation module converts the frequency difference data into frequency difference data relative to the atomic time scale, predicts the clock face frequency reading, determines the weight of each atomic clock according to the forecast residual error, and calculates the atomic time correction through weighted average; the frequency scale control module calculates the frequency offset according to the atomic time correction, the crystal oscillator and the atomic clock signal, and generates control voltage; and the local voltage-controlled crystal oscillator receives the control voltage and reproduces a high-precision time-frequency reference signal synchronized with the atomic clock group. According to the invention, the operation state of the atomic clock is not adjusted, only discrete sampling is carried out, the advantages of the clock group are fused by utilizing the ALGOS algorithm, the long-term stability of the output signal is improved by controlling the high-reliability voltage-controlled crystal oscillator, and the influence of frequency drift, intermittent start and stop and noise interference is effectively inhibited.
Owner:XIAN INSTITUE OF SPACE RADIO TECH

A frequency standard measurement method, device, computer equipment and storage medium

ActiveCN120102972Bincrease the lengthImprove reliabilityFrequency to pulse train conversionAverage filterFrequency measurements
The application provides a frequency standard measurement method, device, computer equipment and storage medium, the method comprises: frequency source output measurement signal is carried out frequency division processing, obtains low frequency pulse signal; using high-precision time interval counter to low frequency pulse signal is carried out delay measurement and time interval counting, and is output in the form of time stamp; by setting a sliding window, using sliding average algorithm to time stamp is carried out sliding average filtering processing, all time stamps are carried out sliding difference to obtain time difference, time difference is grouped according to order and is taken average in group to obtain average time difference; by increasing the length of the sliding window, the number of samples is increased to reduce the statistical error; using average time difference, calculate frequency measurement value, relative frequency deviation and allan variance. The method of the application increases the sliding window, and the frequency measurement result obtained by the algorithm of grouping and averaging the time difference has higher measurement precision and stability.
Owner:XINGHAN SPACE TIME TECH (CHANGSHA) CO LTD

Rapid self-locking system and method for atomic optical frequency standard

The invention discloses an atomic optical frequency standard rapid self-locking system, which comprises a clock laser, and the output of the clock laser is divided into a first path of modulation laser and a second path of modulation laser after sequentially passing through an ultra-stable cavity system, a frequency power modulation optical system and a first spectroscope. The spectral data acquisition system acquires spectral data generated when a first path of modulation laser enters the atomic system physical system, the spectral data acquisition system is respectively connected with the servo feedback system and the integrated automatic control system, and the servo feedback system is connected with the frequency power modulation optical system; the output of the femtosecond optical comb and three paths of modulation laser divided from the second path of modulation laser are subjected to beat frequency to generate beat frequency signals which enter the photoelectric detector; and the laser, the ultra-stable cavity system, the frequency power modulation optical system, the laser frequency scanning system, the atomic system physical system and the femtosecond optical comb are respectively connected with the integrated automatic control system. The invention further discloses a rapid self-locking method for the atomic optical frequency standard, and rapid locking of the optical frequency standard is achieved.
Owner:WUHAN PUSE TECHNOLOGY CO LTD

Laser frequency stabilization electric control system based on modulation transfer spectrum

The invention discloses a laser frequency stabilization electric control system based on a modulation transfer spectrum, and the system is constructed based on a ZYNQ7030 heterogeneous SoC platform, and integrates laser modulation, signal collection, error extraction, feedback control and man-machine interaction functions. Comprising a sinusoidal modulation chain driven by a high-speed DAC and an electro-optical modulator which are used for realizing laser frequency modulation; the MTS signal acquisition link consists of a photoelectric detector, a low-noise amplifier and a high-speed analog-to-digital converter; feedback control is carried out on the frequency of the laser through the precise digital-to-analog converter and the current source circuit. Meanwhile, the system integrates an air cavity temperature control module, a multi-channel communication interface and a man-machine interaction module, and frequency stabilization and system management are achieved. According to the invention, high-precision and high-stability laser frequency locking based on the rubidium atom absorption spectrum can be realized without depending on an external frequency standard, and reliable frequency reference is provided for applications such as high-precision atom physical experiments, quantum sensing, spectral measurement and the like.
Owner:BEIHANG UNIV

A signal processing method and system for a rubidium atomic frequency standard

The application relates to the technical field of signal processing, and provides a signal processing method and system of a rubidium atomic frequency standard, a main frequency standard adopts a double-threshold amplitude comparison circuit, a standby frequency standard adopts a single-threshold amplitude comparison circuit, and the existence of a signal, the validity of an amplitude and a locking state are synchronously monitored; double-threshold detection of the main frequency standard ensures reliability, single-threshold detection of the standby frequency standard ensures readiness for quick switching, and the reliability and switching efficiency are balanced; through preset logic rule fusion analysis, the validity is comprehensively judged in combination with a frequency standard locking signal. A control signal is generated based on a priority rule, the main frequency standard is kept when the main frequency standard is valid, a high-level pulse synchronized with a 10MHz signal zero-crossing point is generated when the main frequency standard is invalid and the standby is ready, an abnormal alarm is triggered when the double frequency standards fail, and the control signal is transmitted to a frequency standard switching circuit through a level conversion subunit, so that the trigger timing requirement of a high-speed switching module is met, quick response switching is ensured, the stability in the switching process is ensured, and the whole is reliable and stable.
Owner:BEIJING GELINK TECHNOLOGY CO LTD

Error calculation method based on pulse sequence with time scale

The invention discloses an error calculation method based on a pulse sequence with a time scale, and belongs to the technical field of electric power measurement testing. The standard time-frequency signal, a high-frequency standard pulse output by the standard electric energy meter and a detected pulse output by the detected electric energy meter are connected to an acquisition processor; the acquisition processor detects a jump edge of the detected pulse in real time based on a clock provided by the standard time frequency signal, and records moments corresponding to a rising edge and a falling edge of the detected pulse; counting the standard pulse in real time, and recording the current count value of the standard pulse at the corresponding moment; combining the moment information with the count value to form an original sampling sequence with a time mark; the calculation processor reads the stored original sampling sequence with the time scale, and calculates the power value, the error value, the waveform characteristic and the jitter index of the detected electric energy meter according to the edge moment of the detected pulse and the corresponding standard pulse count value; and according to the error distribution condition, the stable state of the verification system is monitored in real time, and an alarm is dynamically triggered.
Owner:国网安徽省电力有限公司营销服务中心

Frequency discrimination curve calibration system, method and device

The invention discloses a frequency discrimination curve calibration system, method and device, and relates to the technical field of laser remote sensing, the system locks the output laser frequency of a first laser on a low-concentration atom or molecule absorption peak to obtain an accurate frequency standard; the laser output by the second laser device and the laser output by the first laser device are subjected to beam combination beat frequency, a frequency difference is extracted from a beat frequency signal power spectrum to generate a tuning control signal of the second laser device, and the output laser frequency of the second laser device is locked at any preset frequency offset; the whole laser radar system utilizes an electric control optical switch to realize conversion between a calibration state and a detection state: in the calibration state, laser from the second laser is gated for frequency discrimination curve calibration; and in a detection state, gating the received atmospheric echo signal light for atmospheric remote sensing detection. Therefore, on the basis of ensuring the calibration precision and stability of the frequency discrimination curve, the calibration cost of the frequency discrimination curve is reduced, and the calibration efficiency of the frequency discrimination curve is improved.
Owner:CHINA HUAYUN METEOROLOGICAL TECH GRP CORP

A Partial Discharge Pulse Burst Abnormal Waveform Identification Method Based on Trigger Threshold Moving Window

ActiveCN114924131BMedicineWave shape
This invention relates to a method for identifying abnormal waveforms of partial discharge pulse groups based on a trigger threshold moving window, comprising: Step 1, calculating the average amplitude of a points at the beginning and b points at the end of the recorded waveform to obtain the reference offset value of the recorded waveform; Step 2, removing the reference offset value from the recorded waveform to form a processed waveform; Step 3, establishing an adjustable-duration trigger threshold moving window based on the trigger threshold Yz, and calculating the time standard deviation T and frequency standard deviation B of the data within the moving window when the absolute amplitude within the moving window is greater than or equal to Yz / m, and recording the extreme values ​​and corresponding positions when T×B≥1; Step 4, when the number of extreme values ​​k... j When the value is greater than 1, the time-domain waveform of the currently recorded single pulse is judged as an abnormal waveform; when the number of extreme values ​​k j When the value equals 1, the time-domain waveform of the currently recorded single pulse is determined to be a normal waveform. Compared with the prior art, the present invention has advantages such as good robustness.
Owner:STATE GRID SHANGHAI MUNICIPAL ELECTRIC POWER CO

A frequency standard test expansion card for a frequency standard comparator and a corresponding test method

This invention belongs to the field of electronic signal measurement technology, specifically disclosing a frequency standard test expansion card for a frequency standard comparator and a corresponding test method. The frequency standard test expansion card includes an instruction control module, a signal processing module, a communication interface module, and a signal interface module. The test method provided by this invention is based on the instruction control module and the signal processing module, combined with necessary flow control and data processing. It selectively outputs multiple input frequency signals, then sends the output frequency signals to an external instrument, a frequency standard comparator, for testing, and periodically acquires the test results. After data processing, the test results are encapsulated and reported. This invention can reduce costs and increase efficiency, significantly reducing the use of frequency standard comparators, improving frequency testing efficiency within the same time range, and meeting the different needs of small-batch trial production and large-scale mass production.
Owner:CHINA NAT PETROLEUM CORP +2

Image Data Retrieval Method and System Based on Big Data Surveillance

ActiveCN121765104Bprevent discreteReduce misclassificationBiological modelsCharacter and pattern recognitionCosine similarityData retrieval
This invention relates to the field of intelligent surveillance technology, and more particularly to an image data retrieval method and system based on surveillance big data. The method includes: extracting the visibility and color features of pedestrian key points from surveillance trajectory segments; calculating viewpoint similarity using the cosine similarity of visibility vectors combined with the ratio of frequency standard deviations; selecting comparable key points and weighting them by the minimum visible frequency; calculating appearance similarity by combining color differences; introducing time constraint parameters to optimize the initial clustering distance to obtain a significant clustering distance; clustering matching for the same pedestrian trajectory; and finally establishing a retrieval index to complete image data retrieval. This invention improves pedestrian information retrieval performance by extracting key point visibility and color information, fusing optimized viewpoint and appearance similarity to construct an initial clustering distance, and optimizing with time constraint parameters to avoid interference from multi-camera scenes.
Owner:WUHAN HUAFENG ELECTRONICS ENG

Frequency time-varying testing device and method for ultra-narrow linewidth laser

The invention provides an ultra-narrow linewidth laser frequency time-varying testing device and method. The device comprises a first 1 * 2 coupler, a self-heterodyne structure, a frequency etalon structure, a frequency drift signal processing module and a frequency noise signal processing module. A short-length delay optical fiber is adopted to form a self-heterodyne structure, and the self-heterodyne structure is matched with a frequency drift signal processing circuit to realize laser frequency drift (less than 100Hz) measurement; meanwhile, a photonic crystal resonant cavity is adopted as a frequency reference and is matched with a frequency noise signal processing circuit to realize laser frequency noise (greater than or equal to 100Hz) measurement. According to the invention, the rapid measurement of the optical frequency drift / noise of different frequency components can be realized, the test device is simple, the measurement precision is high, the measurement range is wide, and a foundation is laid for the frequency characteristic evaluation of the ultra-narrow linewidth laser.
Owner:BEIJING AUTOMATION CONTROL EQUIP INST +1

High-precision timing system equipment based on rubidium clock and constant-temperature crystal oscillator

The invention provides high-precision timing equipment based on a rubidium clock and a constant-temperature crystal oscillator, and belongs to the technical field of time-frequency synchronization. The system comprises a main control card, a monitoring card, a time code output branching card, a frequency scale output branching card, a Beidou receiver card, a 1553B bus interface card, an NTP and a PTP time service card which are installed on a VPX backboard. The time code output shunt card supports output of various time service signals, the frequency scale output shunt card supports output of various frequency scale signals, and the 1553B bus interface card can convert the time service signals of a serial port protocol into time service signals of a 1553B bus form suitable for the fields of avionics systems and the like; the NTP time service card and the PTP time service card are provided with optical fiber communication interfaces and Ethernet communication interfaces at the same time, and optical time service and electric time service can be achieved. According to the invention, a mode of'rubidium clock + crystal oscillator 'is adopted to realize time-frequency signal output, and a series clock taming mode is adopted, so that the problem that signals with high time-keeping precision and high-index frequency cannot be met at the same time in the prior art is solved.
Owner:SHENZHEN YUANDONG HUAQIANG NAVIGATION & ORIENTATION CO LTD

A signal processing method and system for a rubidium atomic frequency standard

The application relates to the technical field of signal processing, and provides a signal processing method and system of a rubidium atomic frequency standard, a main frequency standard adopts a double-threshold amplitude comparison circuit, a standby frequency standard adopts a single-threshold amplitude comparison circuit, and the existence of a signal, the validity of an amplitude and a locking state are synchronously monitored; double-threshold detection of the main frequency standard ensures reliability, single-threshold detection of the standby frequency standard ensures readiness for quick switching, and the reliability and switching efficiency are balanced; through preset logic rule fusion analysis, the validity is comprehensively judged in combination with a frequency standard locking signal. A control signal is generated based on a priority rule, the main frequency standard is kept when the main frequency standard is valid, a high-level pulse synchronized with a 10MHz signal zero-crossing point is generated when the main frequency standard is invalid and the standby is ready, an abnormal alarm is triggered when the double frequency standards fail, and the control signal is transmitted to a frequency standard switching circuit through a level conversion subunit, so that the trigger timing requirement of a high-speed switching module is met, quick response switching is ensured, the stability in the switching process is ensured, and the whole is reliable and stable.
Owner:BEIJING GELINK TECHNOLOGY CO LTD

Integrated Michelson optical frequency scale and displacement measurement system based on pyramid array feedback

PendingCN121452938AUsing optical meansInterference resistanceAbsolute frequency
The invention discloses an integrated Michelson optical frequency scale and displacement measurement system based on pyramid array feedback. The device comprises a Michelson optical frequency standard system (optical frequency standard system for short) and a Michelson displacement measurement system (displacement measurement system for short), and the optical frequency standard system and the displacement measurement system share the same reference arm. According to the invention, quantum spectral lines are used as absolute frequency reference to generate stable and accurate optical frequency standard signals, and the optical frequency standard signals are used as the reference of displacement measurement to realize organic unification of time frequency and displacement measurement; an optical frequency signal output by the optical frequency standard system has a relatively strong anti-interference capability to an external environment, and the resolution of the displacement measurement system can be improved; in order to solve the interference problem of the pitching inclination angle of a measuring arm cavity mirror in displacement measurement and tiny movement in the non-displacement measurement direction, the invention provides a reflecting mirror adopting an integrated pyramid array as a composite cavity, so that the stability and the robustness of a displacement measurement system can be improved, and the measurement range and the measurement resolution are optimized.
Owner:PEKING UNIV +1

A method for detecting time-frequency fingerprint characteristics of a frequency source

ActiveCN115480099BAdd descriptionincrease awarenessFrequency measurement arrangementPattern recognitionFrequency stabilization
This invention relates to a method for detecting the time-frequency fingerprint characteristics of a frequency source, belonging to the field of frequency detection technology. The method acquires the clock signal of a frequency standard source, extracts a time-frequency fingerprint feature region from the curve of the clock signal's frequency stability changing with sampling time, and obtains the time-frequency fingerprint characteristics of the frequency source by detecting the time-frequency characteristics of this region. This fingerprint is then compared with the original, inherent time-frequency fingerprint characteristics to identify the type of the frequency standard source and the individual frequency source. This invention creatively proposes using the detection of a specific curve characteristic within the frequency source's stability changing with sampling time as a unique time-frequency fingerprint feature region to identify the type and individual characteristics of the frequency source. This achieves the application objective of uniquely identifying and determining the health status of a specific electronic device by detecting the time-frequency fingerprint characteristics of the frequency source. The method is unique and has good market application prospects.
Owner:周渭 +1

Device and method for improving stability and output phase noise of broadband frequency-mixing phase-locked loop

The invention discloses a device and method for improving stability and output phase noise of a broadband frequency-mixing phase-locked loop, and belongs to the technical field of electronic integration, and the device comprises a crystal oscillator, a power divider, an FPGA controller, a frequency-mixing phase-locked loop and a frequency scale phase-locked loop. A plurality of narrowband voltage-controlled oscillators are adopted to replace a traditional broadband voltage-controlled oscillator, and a radio frequency one-out-of-N switch selection mechanism is combined, so that the problem of phase noise deterioration caused by a DAC (Digital-to-Analog Converter) capture mode is avoided, and meanwhile, the stability of a phase-locked loop and the quality of an output signal are improved. According to the invention, the output phase noise can be obviously reduced, the requirement of a complex system for a wide-band signal is met, and the method has important application value.
Owner:CHENGDU SHIYUAN FREQUENCY CONTROL TECH

A frequency hopping phase-continuous frequency synthesizer and a method of controlling the same

The application discloses a frequency hopping phase continuous frequency synthesizer, which comprises a thermostat crystal oscillator, a power divider, a clock distributor, a comb spectrum generator, an FPGA, a diplexer, a first filter, a DDS, an M-path S-waveband switch filter group, a second filter, a first amplifier, a frequency mixer, an N-path S-waveband switch filter group, a second amplifier, a frequency doubler, a third filter and a third amplifier, and discloses a frequency hopping phase continuous frequency synthesizer control method. The frequency synthesizer adopts a brand-new frequency standard frequency, an intermediate frequency frequency and a control logic calculation method, realizes frequency hopping phase continuity of DDS output frequency, and solves the problem of phase continuity of small-step jumping of the frequency synthesizer. The frequency synthesizer has the advantages of low noise and large-step jumping of direct analog frequency synthesis technology, and has the characteristics of small-step jumping of direct digital type.
Owner:CHENGDU LIANBANG MICROWAVE COMM ENG

Selectively enhancing the resonance frequency and quality factor of on-chip capacitors

The technology described herein is directed towards a capacitor with a modified design (relative to standard capacitors), in which a first conductor is coupled to a second conductor via a distributed array of conducting interconnects through a dielectric that separates the conductors. The array of interconnects facilitates electrical surface current flow between the first conductor and the second conductor, and determines the self-resonant frequency of the capacitor. The array (or enlarged area) of conducting interconnects, not present in standard capacitors, results in capacitors with larger self-resonant frequency, e.g., having a substantially stable capacitance over a range of high radio frequencies, including millimeter wave frequencies. This further provides an improved quality factor. The improvements resulting from the technology described herein facilitate more optimal surface current density. The modified capacitor provides benefits in various circuits, e.g., in an impedance or a millimeter wave frequency phase shifter for antenna elements.
Owner:DELL PROD LP

Full-scale error live calibration device and calibration method of low-voltage current transformer

The invention discloses a full-scale error live calibration device and calibration method for a low-voltage current transformer, and the device comprises a current control unit which is used for outputting full-scale calibration current control signals of all frequencies; the pilot frequency calibration current source is used for outputting a full-scale pilot frequency current signal based on the current control signal and injecting the full-scale pilot frequency current signal into the current transformer to be measured and the standard current transformer; the opening current sensor is used for measuring a background current signal in real time; the signal decoupling unit is used for acquiring the frequency mixing error voltage signal and eliminating a voltage component generated by the background current signal in the frequency mixing error voltage signal so as to acquire a pilot frequency error voltage signal; the error measurement unit is used for calculating a ratio error and a phase error of the current transformer to be measured based on the pilot frequency standard signal and the pilot frequency error voltage signal; and the data processing unit is used for determining a calibration error under power frequency mapping based on the ratio error and the phase error under each different frequency.
Owner:CHINA ELECTRIC POWER RESEARCH INSTITUTE CO LTD +2

A power system inertia distribution evaluation method and system and a storage medium

The present application relates to the technical field of power system, and more particularly to a kind of power system inertia distribution evaluation method, system and storage medium, method includes: the active power and frequency measurement data of power system power source side grid-connected node are collected, and measurement data is filtered and cleaned, bad data is rejected and interpolation reconstruction, and normalization processing is carried out, form active power standard data sequence and frequency standard data sequence;Combining sliding window technology and using detrended fluctuation analysis active power standard data sequence and frequency standard data sequence, identify the initial time of system disturbance occurrence;Based on generator group power frequency response characteristics, construct inertia evaluation analytical model from energy point of view;Through the continuous input of real-time measurement data and model iterative calculation, dynamically update inertia evaluation result, and determine final inertia evaluation value according to quasi-steady state result.The present application can realize the real-time perception of inertia distribution in power grid, and does not need excessive dependence on existing high-precision model.
Owner:STATE GRID JIANGSU ELECTRIC POWER CO LTD RESEARCH INSTITUTE +1

High-precision repetition rate locking apparatus for ultra-fast laser pulse

A high-precision repetition rate locking apparatus for an ultra-fast laser pulse includes: an electronic controlling component comprising: a standard clock, configured to provide a high-precision frequency standard; a pulse generator (PG), configured to provide an electrical pulse signal with adjustable repetition rate, pulse width and voltage magnitude; and a signal generator (SG), connected to the standard clock and the PG, and configured to provide a stable frequency signal for the PG, a phase-shift adjusting component, connected to the electronic controlling component and configured to implement phase modulation through electrically induced refractive index change; a resonant cavity component, comprising a phase shifter, a doped fiber, a laser diode, a wavelength division multiplexer and a reflector, and configured to generate a mode-locked pulse; and a detection system, configured to measure a repetition rate of an output pulse.
Owner:CHONGQING INST OF EAST CHINA NORMAL UNIV +6

Measurement type picometer-scale displacement resolution generation method based on twin double cavities

The invention discloses a measurement type picometer-level displacement resolution generation method based on twin double cavities, and the method comprises the steps: employing a group of twin Fabry-Perot cavities with matched parameters, and the twin Fabry-Perot cavities comprise a measurement cavity and a reference cavity; based on the PDH technology, the lasers of the two lasers are locked to harmonic peaks of the measuring cavity and the reference cavity respectively, and then the resonant frequency is measured through an optical frequency comb to represent the displacement amount; a set frequency stepping signal is output through an optical phase-locked loop, the frequency stepping signal is converted into a voltage control signal to be loaded to a PZT of a measurement cavity, the PZT is driven to drive a reflector to move so as to change the cavity length, and a controllable picometer-scale standard displacement step is generated. According to the invention, on the basis of twin Fabry-Perot cavity resonant frequency differential mode detection, a common mode signal caused by Fabry-Perot cavity environment noise can be suppressed, the cavity length displacement is directly traced to an optical frequency standard, and absolute traceability and high-resolution measurement of a picometer-level displacement signal are realized.
Owner:NATIONAL INSTITUTE OF METROLOGY CHINA

Stable optical clock system based on double microcavity optical comb and two-photon transition and implementation method

This invention discloses a stabilized optical clock system and its implementation method based on a dual-microcavity optical comb and two-photon transitions. The system includes a microcavity optical comb section, a locking section, and a photodetector. The microcavity optical comb section contains two SiO2 microchip ring cavity optical comb oscillators, with center wavelengths matched to the two-photon transition lines of rubidium and cesium atoms, respectively. The locking section provides an atomic reference frequency through a two-photon transition generator, and combines a six-way phase-locked loop, an acousto-optic modulator, and a phase modulator to achieve initial frequency locking of the optical comb, interlocking of the repetition frequency, and suppression of thermally induced detuning. The photodetector converts the stabilized optical comb repetition frequency into an RF frequency standard output. This invention solves the problems of complex system design, large integrated size, cumbersome locking structure, and wavelength mismatch in existing ultra-high frequency stabilized atomic clock technologies.
Owner:ZHONGKE QIDI OPTOELECTRONIC TECH (GUANGZHOU) CO LTD

A multi-source heterogeneous fusion distributed layered time scale system construction method, system, device and storage medium

PendingCN122331703AData centerVirtual time
The application discloses a multi-source heterogeneous fusion distributed layered time scale system construction method, system, equipment and storage medium, and relates to the technical field of time frequency standard and time reference construction. The method comprises the following steps: a distributed layered framework containing a plurality of parallel first-level units in a first layer and one second-level unit in a second layer is constructed, and space, type and affiliation information of time frequency sources are collected; the time frequency sources are grouped according to a grouping strategy, each unit is arranged in different data centers, and a distributed first-level time scale is generated through differential processing; the first-level time scale is represented as a virtual time frequency source and participates in comparison, and is input into the second-level unit; a second-level time scale is generated through virtual comparison; and based on a layered time scale algorithm and an elastic strategy, a final time scale output is dynamically updated and generated. The application can continuously output a time scale meeting stability and continuity requirements, and improves the expandability and elasticity of a time reference system.
Owner:BEIHANG UNIV

A dynamic displacement sensor calibration device based on a rotating sinusoidal edge turntable

The present invention discloses a dynamic displacement sensor calibration device based on a rotating sinusoidal edge turntable. This device relates to the technical field of displacement sensor calibration and includes the following steps: generating a multi-band standard sinusoidal displacement signal by driving a sinusoidal edge turntable to rotate based on a rotational speed generator; converting the rotational motion into periodic radial standard sinusoidal displacement changes through an approximate sinusoidal edge structure; adjusting the displacement amplitude by replacing sinusoidal edge turntables with different amplitudes based on the range, bandwidth, and probe size of the displacement sensor to be calibrated; and adjusting the sinusoidal displacement frequency by adjusting the speed parameter of the rotational speed generator; and calculating the sensor bandwidth based on the amplitude attenuation by fitting an amplitude-frequency characteristic curve using a least squares method with a preset attenuation threshold based on a dynamic sensitivity parameter. The device can generate medium- and high-frequency standard sinusoidal displacements, meeting the dynamic sensitivity and bandwidth calibration requirements of dynamic displacement sensors. The device has the characteristics of a wide range, a small size, and a low cost.
Owner:NATIONAL INSTITUTE OF METROLOGY CHINA