1059 results about "Crystal oscillator" patented technology

The invention discloses an anti-fouling piezoelectric ceramic membrane which comprises a support body, a coil and a piezoelectric ceramic separation layer, the support body is made of porous ceramic with a through hole in the middle; the coil is a closed loop composed of a lead coil and a crystal oscillator; the piezoelectric separation layer is coated on the inner wall of the through hole of the support body; and the coil is arranged between the support body and the piezoelectric ceramic separation layer. When a medium containing electrolyte passes through a membrane hole, the coil generates induction direct current, the direct current is converted into positive wave pulse current through the oscillator, the wound and overlapped piezoelectric ceramic membrane separation layer is excited, ultrasonic vibration is generated, and therefore the membrane dirt blocking condition is reduced, the use efficiency of the ceramic membrane is improved, and the maintenance and use cost is reduced.

The invention relates to a self-diagnosis method for a state terminal of a substation measurement system, which comprises the following steps of: comparing signal values at different sampling nodes of signals from the same physical source in each measurement channel through the state terminal, and judging that the channels have physical chain degradation or poor contact; performing perturbation modulation on a measurement sampling process based on a clock signal controlled by a crystal oscillator in the state terminal, and if response deviation abnormity is detected, judging that a sampling time base has drift, time sequence disorder or cache backlog so as to identify a time base health state of a sampling chain in the terminal; in the operation process of the transformer substation, response differences generated by the excitation in different measurement channels are collected, and if response delay, amplitude distortion or jitter starting point deviation is found, it is judged that the anti-interference capacity of the corresponding channel is degraded; and according to the electric energy change rhythm sensed by the terminal in real time, adaptively adjusting the sensitivity threshold value of the jump response, and if frequent misjudgment or slow response of the jump response is detected, marking that the behavior sensitivity of the terminal sampling system is abnormal.

The invention discloses a temperature drift compensation method for a miniature crystal oscillator chip, and particularly relates to the field of temperature drift compensation for electromagnetic interference signal measurement, which comprises the following steps of: arranging a double-shaft Hall sensor array around a temperature sampling channel of the miniature crystal oscillator chip, and carrying out spatial distribution acquisition on a low-frequency electromagnetic field in a chip operation environment; generating an electromagnetic disturbance signal for representing a parasitic electromagnetic interference behavior; and pilot frequency convolution processing is carried out on the electromagnetic disturbance signal and a thermal response signal obtained in a temperature sampling channel, coupling response characteristics related to an electromagnetic interference behavior are extracted, and a spectrum fitting template of an electromagnetic parasitic injection behavior is constructed. A low-frequency electromagnetic disturbance sensing channel is synchronously introduced outside a temperature sampling path, and an interference identification, stripping and compensation dynamic linkage mechanism is constructed to realize active detection and correction of latent electromagnetic interference components in a temperature response signal, so that the problems of frequency compensation error and long-term offset accumulation in the prior art are solved.

The invention provides a dynamic high-precision PTP (Precision Time Protocol) time synchronization system realized based on an FPGA (Field Programmable Gate Array), which comprises a master device and a slave device, and the master device and the slave device are connected through a PHY (Physical Layer) to carry out PTP time synchronization; the master device and the slave device have the same structure and comprise an FPGA and a voltage-controlled crystal oscillator; in the master device, the FPGA obtains the frequency difference and the phase difference between the master device and an externally input reference source, further adjusts the frequency of a voltage-controlled crystal oscillator, corrects a local time mark, and sends a PTP message to the slave device; and in the slave equipment, the FPGA obtains the frequency difference and the phase difference between the slave equipment and the master equipment based on the received PTP message, so that the frequency of the voltage-controlled crystal oscillator is adjusted, and the local time scale is corrected. According to the invention, low-cost and high-precision PTP time synchronization is realized.

The utility model belongs to the technical field of vacuum evaporators, and discloses a crystal oscillator probe structure which comprises a crystal oscillator water pipe, a probe assembly is arranged at the bottom of the crystal oscillator water pipe, an installation structure is arranged on the inner wall of the probe assembly, and a driving assembly located outside the probe assembly is arranged at the top of the installation structure. A clamping structure is arranged in the probe assembly, the probe assembly comprises a mounting frame, and a detection head is movably sleeved with the mounting frame. According to the utility model, the detection head and the connecting plate are arranged, the reverse rotating block is rotated, and the whole detection head is limited through the clamping block, so that the screw rod is screwed out of the detection head, and the connecting plate, the protection plate, the limiting frame and the supporting frame are driven to move upwards and a wafer in the limiting frame is driven to move out of the mounting frame through the elastic force of the spring I; therefore, the wafer can be conveniently replaced by an operator, and the replacement efficiency of the wafer is improved.

The invention provides a crystal oscillator monitoring method and system based on a multi-sensor network. The method comprises the following steps: acquiring operation environment data of the quartz crystal oscillator, monitoring an output signal of the quartz crystal oscillator, and acquiring output frequency and time for measuring the crystal oscillator in each batch; calculating the daily frequency change rate of the quartz crystal oscillator, and establishing an aging linear regression equation of the quartz crystal oscillator through a least square method based on the operation environment data, the output frequency, the daily frequency change rate and the time; and predicting an output frequency prediction value of the quartz crystal oscillator based on the aging linear regression equation, and performing frequency compensation on the quartz crystal oscillator according to the difference between the output frequency prediction value and a target frequency prediction value. Through the method and the corresponding system, the frequency stability and the anti-interference capability of long-term operation of the quartz crystal oscillator system and the overall operation reliability of the terminal equipment can be greatly improved.

The invention belongs to the technical field of medical robots, and discloses a surgical robot accurate pose real-time registration method and system based on multi-sensor fusion, and the system comprises a multi-source sensing collection assembly; a time-space calibration mechanism; fusing a resolving platform and an exception elimination platform; a deformation sensing and dynamic compensation device; and a registration result closed-loop feedback unit. According to the invention, a multi-source sensing acquisition assembly and a synchronous control board are integrated on a hardware level, a nanosecond timestamp is generated by using a high-precision clock driven by an onboard crystal oscillator, and a cross-correlation delay calculation chip is combined to execute a cross-correlation function method delay estimation formula, so that microsecond-level accurate correction of delay amount among sensing sources is realized; the coordinate transformation unit automatically selects a matched calibration matrix according to a correction result, multi-source data such as optical positioning, inertial measurement, a torque sensor, ultrasonic or electromagnetic positioning and the like are unified to a global rectangular coordinate system, and the structure can effectively ensure the consistency of time and space references of data output by different sensors.

The invention discloses a multifunctional hydraulic system experiment table, which relates to the technical field of hydraulic system experiment tables and comprises a time base line synchronous control module, a phase lock correction stability control module, a false peak identification and correction module, a multi-dimensional fault-tolerant judgment control module and a reverse energy slow-release anti-reverse module. And the time base line synchronous control module is used for establishing a cross-sensor unified time base line control structure, generating a synchronous reference surface by using a high-stability crystal oscillator signal, and executing nanosecond phase calibration on sampling signals of the pressure sensor and the flow sensor by taking the synchronous reference surface as a unified time reference. According to the invention, high-precision synchronous acquisition of pressure and flow signals is realized through unified time base line and phase locking correction, and high-pressure transient test data is ensured to be real and stable; and meanwhile, control logic is reconstructed, and an energy slow release strategy is introduced, so that the pressure relief process is stable and controllable, pump reverse rotation and structural impact are avoided, and the safety, reliability and self-healing stability of the experiment table are remarkably improved.

The invention discloses a full-localization ultra-high-speed multi-channel ADC (Analog to Digital Converter) acquisition and processing platform, and relates to the technical field of signal processing. The platform comprises a high-stability clock distribution calibration module, a synchronous acquisition and pulse injection module, a pulse detection and integer deviation module, a coarse-grained translation alignment module, a sub-sampling phase extraction module, a fractional delay interpolation alignment module, a hierarchical storage and flow control module and a high-speed interface synchronous output module. Multi-channel sampling clock synchronization is realized through FPGA dynamic phase adjustment; performing coarse-grained translation by injecting calibration pulses to detect integer deviation, extracting a sub-sampling phase difference, and adopting fractional delay filtering to realize sub-sampling precision alignment; hierarchical storage and intelligent flow control are carried out according to priorities, and synchronous data flow is output through a domestic high-speed interface; through a full-flow domestic chip and a synchronous correction technology, sub-sampling precision alignment and hierarchical flow control output of a multi-channel ADC at an ultrahigh sampling rate are realized.

The invention discloses a crystal oscillator circuit fault classification technology based on a multi-source information fusion network, and belongs to the technical field of analog circuit fault diagnosis. Firstly, a multi-source data set of different measurement points of the crystal oscillator circuit is acquired; carrying out conversion from a time domain to a frequency domain on the data set by utilizing fast Fourier transform; extracting data fault features by using a convolutional neural network, and performing a trust distribution function under each piece of source data by using a softmax classifier; fusing different trust distribution functions under the multi-source data by adopting a D-S evidence theory to obtain a final diagnosis result and diagnosis probability output, and calculating cross entropy loss; and finally, training model parameters through back propagation to obtain a final diagnosis model. According to the method, the time-frequency transformation algorithm, the deep neural network algorithm and the information fusion algorithm are combined, a multi-source information fusion network is constructed, the defects of an existing diagnosis model in crystal oscillator circuit fault classification are overcome, and the accuracy and stability of crystal oscillator circuit fault diagnosis are remarkably improved.

The invention relates to the technical field of cable fault positioning, in particular to a cable fault accurate positioning method based on multi-channel synchronous acquisition, which comprises the following steps: S1, constructing a multi-channel adaptive acquisition system which comprises a main controller, a multi-channel acquisition module, a synchronous control module and a data transmission module; s2, multi-channel data synchronous acquisition is carried out through the synchronous control module, wherein the multi-channel data comprises impedance data, temperature data, partial discharge signals and insulation resistance data; during use, through a multi-channel adaptive acquisition design, monitoring channels can be flexibly selected according to cable materials, operation years and environmental conditions, different aging fault characteristics are comprehensively covered, the fault omission ratio and the false alarm rate are reduced, different types of low-voltage cables are adapted, a synchronous scheme of constant-temperature crystal oscillator and hardware triggering is adopted, and the reliability of the system is improved. The method does not need to depend on a GPS / PTP time service module, is favorable for saving cost input, and eliminates environmental interference and single parameter false triggering.

The invention belongs to the technical field of clock synchronization. The invention provides an unmanned aerial vehicle communication clock synchronization compensation device and method based on GPS / Beidou second pulse. According to the embodiment of the invention, a second pulse signal and a UTC timestamp are obtained; after several rounds of counting and sliding filtering are carried out on the second pulse signal interval time, the actual frequency and nominal value deviation of the crystal oscillator is calculated; the actual frequency and nominal value deviation of the crystal oscillator are stored, and the crystal oscillator drift model is updated; and dynamically adjusting the output clock frequency according to the nominal value deviation, and compensating the crystal oscillator error to obtain a compensated clock signal. And the second pulse loss duration is monitored, and the crystal oscillator drift model is updated according to the nominal value deviation in the storage module so as to predict the future clock deviation. And within the period of validity of the pulse per second, the clock synchronization error is reduced to improve the synchronization precision. And under the condition of GPS / Beidou, the synchronization precision can be maintained longer than that of a single GPS / Beidou method. And frequency offset automatic compensation along with temperature change can be realized.

The invention belongs to the technical field of satellite communication, navigation and precision measurement, and discloses a constant-temperature crystal oscillator automatic taming and calibration method and system based on GPS pulse per second, which can accurately tame and calibrate internal clocks such as a rubidium atomic clock and a 10MHz constant-temperature crystal oscillator through a GPS pulse per second signal, and adopts a novel clock synchronization algorithm to realize the automatic taming and calibration of the constant-temperature crystal oscillator. Through accurate frequency calibration and phase synchronization, high-stability and high-precision second pulse signals and 10MHz frequency clock signals are output.

The invention discloses a multi-protocol compatible hydropower station field bus photoelectric signal synchronous acquisition device and method, and relates to the technical field of industrial bus testing, the device comprises a core control layer, a signal conditioning layer, a photoelectric interface layer, a clock synchronization layer, a power management layer and a data storage and transmission layer; the core control layer adopts a dual-core framework of a domestic Loongson 2K0300 main control unit and a domestic FPGA (Field Programmable Gate Array) time sequence control unit; the clock synchronization layer adopts a two-stage synchronization mechanism of'local crystal oscillator time sequence control + NTP network clock calibration '; and the signal conditioning layer is integrated with a multi-protocol self-adaptive conditioning module and an industrial-grade anti-interference module. The method comprises the steps of clock initialization and calibration, parameter configuration, photoelectric signal parallel acquisition and time sequence synchronization, and data preprocessing and transmission, so that synchronous acquisition of six types of bus protocol photoelectric signals is realized. The system has the advantages of multi-protocol compatibility, autonomous controllability, good portability and the like, and provides reliable data support for bus communication quality evaluation and fault diagnosis.

The invention is suitable for the technical field of wireless audio, and provides a satellite flash multi-device cooperative wireless earphone audio synchronization optimization method, which comprises the following steps: eliminating crystal oscillator drift errors through radio frequency signal flight time measurement, and electing a main device by a dynamic election algorithm to realize clock synchronization; a motion state prediction track is monitored in real time, the depth of a buffer area is adjusted, sound velocity time delay is compensated in combination with environmental parameters, and a key frequency band redundant packet is enhanced in a physiological activity window period; a Polar code dynamic redundancy mechanism and multipath reflection are fused to cope with channel interference; an audio stream is decomposed into key frames and non-key frames, and a transmission strategy is optimized through multi-link transmission, dynamic auction and preemptive scheduling. According to the scheme, the problems of clock asynchronization, motion lagging, environment interference and the like in multi-device cooperation can be solved, the audio synchronization precision and the anti-interference capability can be effectively improved, and the method is suitable for a high-precision wireless audio transmission scene.

The invention discloses a system reference clock frequency accuracy automatic calibration circuit and a calibration method thereof, and belongs to the technical field of frequency sources, the calibration circuit comprises a first crystal oscillator, a first power divider, a second power divider, a second crystal oscillator, an analog switch, a radio frequency switch, a detector, a comparator, an FPGA controller, a digital analog converter, an operational amplifier and a temperature sensor. When an external high-precision reference clock is accessed, the FPGA controller automatically switches a frequency measurement reference, performs high-precision frequency measurement on a 100MHz signal output by the first crystal oscillator, and judges whether calibration is needed or not according to frequency offset; if calibration is needed, the output voltage of the digital-to-analog converter is adjusted, the Vc end of the first crystal oscillator is controlled after operational amplification, and frequency closed-loop adjustment is achieved. According to the method, the crystal oscillator does not need to be disassembled, calibration is rapidly completed on site, and system availability and long-term frequency stability are remarkably improved.

The invention discloses a crystal oscillator taming system based on Kalman filtering and adaptive PID, and relates to the technical field of time-frequency equipment. Comprising a crystal oscillator time frequency module used for generating a local time frequency signal, a reference module used for receiving an external reference time frequency signal, an error measurement module used for measuring the phase deviation between the local time frequency signal and the reference time frequency signal, and a Kalman filtering estimation module used for performing Kalman filtering estimation based on the phase deviation. The Kalman filtering module is used for outputting phase deviation estimation and covariance estimation and adaptively adjusting PID parameters according to the phase deviation estimation, the position deviation estimation and the covariance estimation; the control feedback module is used for superposing the voltage-controlled voltage adjustment quantity to the crystal oscillator time frequency module to adjust the output frequency of the crystal oscillator; according to the method, the crystal oscillator taming parameters are dynamically adjusted through Kalman filtering in combination with self-adaptive PID, high-precision and robust taming of the crystal oscillator is achieved, and the long-term frequency stability and the time synchronization precision of the crystal oscillator are improved.

A method for measuring the dynamic frequency of a high-precision crystal oscillator comprises the following steps: 1) setting a target frequency on an upper computer, communicating with a single chip microcomputer in a lower computer through a serial port, and sending the target frequency to the lower computer; and 2) acquiring a signal of the tested wafer in the alternating electric field. And 3) making a frequency lookup table. And 4) calibrating the signal of the tested wafer. And 5) carrying out AD conversion on the calibrated voltage signal, outputting a code of the calibrated voltage signal to a single-chip microcomputer, finding out a frequency corresponding to the code, sending the frequency to an upper computer through a serial port, and displaying the measured frequency of the quartz wafer. According to the invention, high-precision and low-cost frequency measurement can be realized.

The invention discloses a high-precision clock taming and signal shaping method and device for a satellite timing system. The method comprises the following steps of: counting and measuring a reference pulse per second received in real time by using a local high-frequency clock signal output by a local voltage-controlled crystal oscillator to obtain a phase counting deviation sequence of the local high-frequency clock signal relative to the reference pulse per second; inputting the phase counting deviation sequence into the frequency control closed-loop model, analyzing the historical state characteristics of the phase counting deviation sequence, and calculating a frequency adjustment instruction for the local voltage-controlled crystal oscillator; the frequency adjusting instruction is converted into an analog voltage signal, a local voltage-controlled crystal oscillator is driven to adjust the output frequency, and a tamed local high-frequency clock signal is obtained; the tamed local high frequency clock signal is utilized to drive phase warping logic to generate a local pulse per second synchronized with the reference pulse per second. According to the invention, through adaptive closed-loop control and phase regulation, precise taming of crystal oscillator frequency and high-precision shaping of output signals are realized.

The invention discloses a constant-temperature crystal oscillator and rubidium clock combined taming device and method, and relates to the technical field of time frequency, and the device comprises a single-chip microcomputer, an FPGA module, a TDC module, a rubidium atomic clock and a constant-temperature crystal oscillator. The FPGA module is connected with the single-chip microcomputer, the TDC module, the rubidium atomic clock and the constant-temperature crystal oscillator, the FPGA module is used for receiving a reference 1PPS signal input from the outside, the single-chip microcomputer is connected with the constant-temperature crystal oscillator through the DAC module, the TDC module is connected with the single-chip microcomputer through an SPI bus, the TDC module is used for measuring the phase difference, and the single-chip microcomputer is used for adjusting the voltage control of the constant-temperature crystal oscillator or the frequency of the rubidium atomic clock; and the FPGA module communicates with the rubidium atomic clock through a UART serial port. The output frequency has the characteristics of a constant-temperature crystal oscillator and a rubidium atomic clock at the same time, and low noise and high stability are achieved; a taming state can be quickly entered to output an accurate clock without waiting for preheating of a rubidium clock during startup; a serial taming mode is avoided, parallel taming is adopted, and when one clock source is abnormal, clock hot backup can be achieved.

The invention discloses a low-cost precise time keeping method, system and device based on a gating circulation unit, and relates to the technical field of power grid measurement. The method is executed when the synchronous phasor measurement device cannot receive external signals, and comprises the following steps: monitoring operation parameters which influence the frequency stability of an internal crystal oscillator of the phasor measurement unit in real time; calculating a current frequency error of the crystal oscillator in real time by using a crystal oscillator frequency drift prediction model based on a gated cycle unit network based on the operation parameters; generating a time correction amount according to the current frequency error; and applying the time correction to a local clock of the phasor measurement unit to compensate the frequency drift of the crystal oscillator so as to realize accurate time keeping. According to the invention, through accurate prediction of crystal oscillator errors and lightweight software compensation, the synchronous phasor measurement device adopting a low-cost crystal oscillator can also realize long-time high-precision time keeping, the hardware cost is obviously reduced, and the reliability of power grid monitoring during the Beidou / GPS lock losing period is improved.

The invention relates to a clock compensation method, device and equipment for fusing a terminal and an electric energy meter and a medium, and relates to the technical field of electric energy meter calibration, and the method comprises the steps: collecting detection data, compressing the detection data, and obtaining compressed data; the detection data comprises a crystal oscillator frequency and an environment temperature; uploading the compressed data to a fusion terminal according to a preset uploading period; the fusion terminal analyzes the compressed data to obtain a crystal oscillator frequency deviation and a temperature difference value; inputting the crystal oscillator frequency deviation and the temperature difference into an LSTM model, and outputting a dynamic compensation factor of each electric energy meter; broadcasting the dynamic compensation factor and the second pulse signal to each electric energy meter; and acquiring a compensation factor and a second pulse signal, and calibrating and metering according to the compensation factor and the second pulse signal to obtain clock data. The LSTM model is combined with the temperature-drift coupling relation to generate a targeted compensation factor, so that the calibration precision is improved, and the system operation cost is reduced at the same time.

The invention discloses a Beidou PTP master clock device based on chip atomic clock timekeeping, which integrates a chip atomic clock and a Beidou satellite time service signal, and comprises the following steps: firstly, receiving a Beidou satellite signal through a satellite receiving module, and generating an accurate 1PPS signal, a TOD signal and a 10MHz frequency signal based on the satellite signal; high-precision time-frequency reference is provided for equipment, and the problem that clock precision is insufficient in a traditional clock synchronization system is solved through the design. Secondly, the first clock board and the second clock board carry chip atomic clocks, and the high stability and low power consumption characteristics of the chip atomic clocks enable the equipment to maintain high precision of clock signals during long-time operation, so that clock errors caused by crystal oscillator frequency drift and aging in a traditional system are avoided. Moreover, the communication core board is connected with the upper computer, so that instructions can be received in real time, and the clock board and the logic control board can be controlled to work, and therefore, the system can quickly respond to the instructions of the upper computer, and accurate time control can be realized.

The invention discloses a real-time time service industrial personal computer, and relates to the technical field of industrial personal computers, the real-time time service industrial personal computer comprises a main control board and a PCIe time code card, the PCIe time code card is connected with the main control board through a PCIe bus, and a GNSS time service module, a temperature compensation crystal oscillator and a PPS synchronous circuit are integrated on the PCIe time code card; the GNSS time service module is used for receiving a satellite signal and outputting a UTC timestamp and a 1PPS pulse signal; the temperature compensation crystal oscillator is used as a local clock source, and the PPS synchronous circuit is used for directly outputting 1PPS signals when satellite signals are available and switching to compensated crystal oscillator PPS signals when the satellite signals are lost; when the industrial personal computer is powered on, the PPS pulse triggers the clock of the main control board to be reset, the PCIe time code card transmits calibrated time-varying data to the main control board in real time, and the main control board distributes a synchronous clock signal with the precision of + / -1 microsecond to external equipment through an industrial bus protocol according to the time-varying data provided by the PCIe time code card. According to the invention, the problem of insufficient time service precision of a traditional industrial personal computer is solved.

The invention relates to the technical field of turning system data processing, in particular to a turning system, relates to the technical field of turning system data processing, and discloses a turning system and a control method thereof. The system comprises a multi-source sensor network deployed in a gearbox, a hub and a transmission chain, temperature, humidity and particulate matter concentration signals are collected through environment self-sensing sensor nodes, and an oil pressure protection threshold value is dynamically adjusted by combining a material thermal expansion coefficient and an environment working condition; the closed-loop feedback module reversely optimizes crystal oscillator compensation parameters through hydraulic response delay data, and interlocking events drive the sand and dust noise feature library to update. According to the method, the problem of interlocking false triggering caused by space-time misalignment of multi-source sensor data is solved, and environment self-adaptive threshold convergence control is realized.

The invention discloses a novel nonlinear rubber steel wire rope composite vibration isolator, and relates to the field of vibration isolators, the novel nonlinear rubber steel wire rope composite vibration isolator comprises a lower clamping plate, an upper clamping plate, rubber and two groups of first steel wire ropes, and the tops and the bottoms of the two groups of first steel wire ropes are symmetrically mounted on the two sides of the upper clamping plate and the lower clamping plate; a gap is reserved between the rubber and the upper clamping plate. According to the novel non-linear rubber steel wire rope composite vibration isolator, when the amplitude of a crystal oscillator is small, vibration energy can be absorbed and dissipated through dry friction damping between the first steel wire ropes, the lower clamping plate, the first steel wire ropes, rubber and the upper clamping plate can generate large dynamic displacement, strong impact can be attenuated, and the vibration isolation effect is good. Meanwhile, a large amount of low-frequency and high-frequency vibration is absorbed and dissipated, and due to the fact that a steel wire rope vibration isolator is small in friction damping and poor in vibration isolation effect during resonance, under the large-amplitude condition, the overall elastic support can be enhanced through the arranged rubber.

The invention relates to a PPS (pulse per second) signal synchronization FPGA (field programmable gate array) timer, which takes a full-localization Fudan micro JFM7K325T chip as a core, comprises a time synchronization unit, a main control unit and a multi-interface unit, and is matched with a real-time clock chip. Wherein the time synchronization unit comprises a synchronization processing module, a time information module and the like, a PPS signal and TOD time information are integrated to generate a PPS + TOD + millisecond timestamp, a 25MHz constant-temperature crystal oscillator is divided into a 250MHz clock in a frequency division manner, and the time sequence precision is guaranteed; through a dual mechanism of satellite master synchronization and RTC bottom compensation, a new timestamp is rapidly combined when PPS is interrupted, and the error is controlled within 4ns; the register array stores timestamps, configuration parameters and running states in a classified mode and supports extension of multiple interfaces such as 422 and IIC and event log power-down storage. According to the invention, high-precision time synchronization, stable operation and full-link localization autonomous controllability are realized, and multi-scene multi-user board card synchronization requirements are met.

The invention relates to the field of electronic circuit design, and discloses a numerical control crystal oscillator circuit with low noise and high stability. According to the circuit, a two-stage voltage regulator is adopted to suppress power supply noise, wide-range high-precision frequency regulation is realized through thick and thin capacitor array regulation, oscillation signal quality is ensured through automatic detection feedback and external programming double-loop control, and a special oscillation starting circuit is arranged to accelerate the starting process of a crystal oscillator. Meanwhile, targeted optimization is carried out on a core circuit and layout in the loop, and noise and distortion are further reduced. The digital controlled oscillator can effectively solve the problems that an existing digital controlled oscillator scheme is narrow in frequency modulation range, large in phase noise and the like, the characteristics of low noise, high stability, rapid starting and the like are achieved, an excellent frequency reference is provided for a wireless communication and high-precision timing system, and the digital controlled oscillator has remarkable practical value.

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.

The utility model discloses a dynamic range current measurement module which comprises a shunt resistance switching unit, a 24-bit precision ADC unit, an MCU processing unit, a crystal oscillator unit, an isolation unit, a 485 interface unit and a power supply unit. The shunt resistor switching unit is used for dynamically selecting shunt resistors with different resistance values according to the magnitude of the current to be measured so as to realize current measurement in a range of 10 uA to 10 A, the shunt resistor of 1 ohm is used in a range of 10 uA to 20 mA, and the shunt resistor of 10 m ohm is used in a range of 20 mA to 10 A; the 24-bit precision ADC unit is used for collecting the analog current signal passing through the shunt resistor and converting the analog current signal into a digital signal; according to the utility model, the dynamic range current measuring module is provided, so that when the current measuring range span is large, the measuring range can be automatically switched, and a tester does not need to replace testing equipment with different measuring ranges; measurement data can be continuously acquired; the electrical isolation loop allows the measurement point to be arranged at any position: a power supply or return wire, measuring part or all of the current.