1345 results about "Crystal oscillator" patented technology

The invention relates to the technical field of robot control, and discloses a heterogeneous robot control system with intelligent and multi-modal perceptual driving, comprising: a quantum clock reference module used for generating a globally synchronized picosecond-level time reference signal and synchronizing a multi-modal sensor clock through a microwave pulse; the multi-mode sensing module comprises an event camera of which the dynamic range is greater than or equal to 120dB, a six-dimensional force sensor of which the noise density is less than or equal to 0.01 N / Hz and an inertial measurement unit of which the zero-bias stability is less than or equal to 0.8 degree / h; and the random differential manifold module adopts a four-layer full-connection neural network, and an input layer receives multi-modal data. According to the invention, a diamond NV color center system of the quantum clock reference module and a microwave pulse coupling technical scheme are adopted, so that a picosecond-level global signal synchronization effect is achieved. Compared with a scheme depending on a traditional crystal oscillator or a GPS clock in the prior art, the defects that electromagnetic interference is prone to occurring and signal jitter is large are overcome, and high-precision time sequence alignment of multi-module cooperation is ensured.

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 provides a crystal oscillator and an atomic clock, and relates to the technical field of oscillators, the crystal oscillator comprises a packaging cavity, a crystal, a temperature sensor and a cantilever beam assembly, the crystal, the temperature sensor and the cantilever beam assembly are arranged in a containing cavity of the packaging cavity, and the packaging cavity is of a vacuum packaging structure. The crystal and the temperature sensor are arranged on the cantilever beam assembly, the crystal and the temperature sensor are electrically connected with different connection points of the packaging cavity through the cantilever beam assembly, and the temperature sensor is arranged around the crystal; the cantilever beam assembly comprises a heating module, and when the temperature sensor monitors that the temperature of the area where the crystal is located is smaller than a preset temperature threshold value, the heating module heats the crystal. The energy loss of air damping to the high-frequency vibration of the crystal is eliminated, the Q value is improved, and the phase noise suppression capability is enhanced; accurate control over the temperature of the area where the crystal is located is achieved, the thermal response speed and the temperature control precision are improved, and the problem that an existing crystal oscillator is poor in stability is solved.

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 a time synchronization parameter tracking method based on unknown Kalman filtering, which belongs to the technical field of time synchronization, and comprises the following steps: S1, modeling the output frequency of a clock crystal oscillator and the change rule of the temperature of the environment where the clock crystal oscillator is located into a quadratic function for a network communication scene with dynamic change of the environment temperature, introducing the temperature influence factor as an unknown quantity into a clock parameter tracking state equation; s2, establishing a clock observation equation by using a precise time synchronization protocol bidirectional information interaction process, and constructing a clock phase offset and clock frequency offset combined tracking state space model under the dynamic change of the environment temperature in combination with a clock state equation; and S3, by using unknown quantity Kalman filtering and taking minimum variance unbiased estimation as a criterion, jointly tracking a clock frequency offset value and a clock phase offset value for the established clock state space model.

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 discloses a processing method of a surface crystal wafer, and relates to the field of surface crystal wafer production. The whole surface crystal wafer is cut from the front side and the back side of the wafer by using a sand blasting and ultrasonic cutting method, and the cut section is arc-shaped based on the sand blasting and ultrasonic cutting method, so that the area of a plated electrode is increased, and the quality of a surface crystal oscillator is improved. The electrode plating operation is carried out based on the whole plate surface crystal wafer, and the essential wet etching step in the traditional processing technology is omitted in the scheme. The invention further discloses a processing method of the surface crystal oscillator based on the whole-board surface crystal wafers, after the whole-board surface crystal wafers are subjected to quality inspection and the positions of defective products are marked, information is uploaded to the server, the whole surface crystal wafers are integrally positioned on the tool, and then the whole-board surface crystal oscillator is processed on the basis of the accurate position of each surface crystal wafer on the whole-board surface crystal wafers recorded by the server and the positions of the defective products. According to the method, the surface crystal wafers are taken one by one by the mechanical arm and fed to the whole plate base, coordinate switching from a regular matrix to a matrix is achieved, the calculation process is simple and accurate, and the step of repositioning in the machining process of the single surface crystal wafer is omitted.

The invention discloses an audio and video acquisition synchronous management method, and relates to the technical field of data synchronization. The method is executed by main control equipment and comprises the following steps: S1, acquiring a satellite time reference through a dual-mode time service module; s2, based on the pulse signal of the temperature compensated crystal oscillator, a master clock signal is generated according to a formula Tmaster = TGPS + alpha delta T + beta (delta f / f0), TGPS is a satellite time reference, alpha is a temperature compensation coefficient and ranges from 0.2 to 0.8, and beta is a frequency drift correction factor; s3, establishing an inter-device time synchronization communication link through an IEEE 1588PTP protocol, and broadcasting a synchronization pulse by the main control device; s4, the data buffer area is adjusted in real time according to the dynamic buffer control formula D (t) = D0 + k1 * (delta t) 2 + k2 * d delta t / dt, k1 = 0.15 ms-2, and k2 = 2.5 ms2 / s; s5, when the network time delay gt is detected; and at 150ms, switching to a local clock compensation mode, and triggering the extended Kalman filter to re-correct the clock parameters. According to the invention, a hybrid synchronization architecture with local clock correction capability is constructed, and self-adaptive time difference compensation without network dependence is realized.

The invention provides a novel vacuum evaporator which comprises a vacuumizing system, a carrier rotating system, a light-operated integrated system, a crystal oscillation system, a heating system, a water cooling system and an evaporation system, and the light-operated integrated system and the crystal oscillation system are arranged in a hollow cavity of a first rotating mechanism, so that cooperative work of rotary coating and real-time detection is realized; a detection light path is shortened, and the signal-to-noise ratio is improved; rotation axis detection ensures data representativeness; the top radiation heating and the side wall conduction heating have a synergistic effect, so that the surface temperature difference of the substrate is smaller than + / -1.5 DEG C, the cooling efficiency of the evaporation system is improved by 40% through the water cooling system, the equipment is highly integrated through the modular architecture design, and the space is saved by 30% through the coaxial design of the carrier rotating system and the detection system; a rotating system, a heating system and a detecting system are cooperatively controlled, a dynamic compensation algorithm automatically adjusts the evaporation rate and the carrier rotating speed by comparing light control data with crystal oscillator data in real time, the film thickness control precision is + / -2 nm, and the refractive index deviation is smaller than 0.5%.

The crystal oscillation system of the vacuum evaporator comprises a first rotating mechanism, a two-stage rotating nested structure is adopted, a second rotating piece independently controls a crystal oscillation piece mechanism to rotate while the first rotating mechanism drives a supporting assembly to achieve revolution of a carrier, and a composite motion trail is formed; a plurality of crystal oscillation sheets can be periodically cut into steam flow for time-sharing measurement, so that the monitoring time of single coating operation is obviously prolonged by 5-8 times; the precisely designed probe cap is matched with the middle rotating shaft driven by the servo motor, so that the positioning precision of + / -0.02 degrees can be realized; a plurality of crystal oscillation sheets arranged in a distributed mode can be started in turn in a programmable mode, so that the coating uniformity control precision is improved to 98.5% or above; a crystal oscillator monitoring point is arranged in a central through hole area of the carrier, and the correlation coefficient of detection data and the actual deposition rate of the substrate is improved to 0.96 from 0.82 of a traditional side arrangement mode by optimizing distribution of a steam flow field, so that the film thickness control reliability is greatly improved.

The invention discloses a method for detecting surface defects of a metal-coated crystal oscillator, which comprises the following steps of: acquiring an initial image of the metal-coated crystal oscillator in real time, and carrying out primary cutting according to coordinates to obtain an image B; converting the image B into a grey-scale map and then carrying out Gaussian filtering to obtain an original image C; setting a fixed threshold, and performing threshold segmentation on the original image C to obtain an image D; performing Hough circle detection on the image D to obtain a circle center coordinate and a radius of the crystal oscillator, and cutting the image B again to obtain an image M; the image M is amplified in proportion and then subjected to bilateral filtering processing, an image E is obtained, electrode deviation detection and surface dirty spot detection are conducted on the image E, and electrode deviation comprises electrode shape deviation and electrode eccentric defects. According to the method, the quantity demanded for samples is small, the problem that dependency on a data set is high is solved, meanwhile, recognizable defect types are added, different detection requirements can be met by adjusting parameters, and result visualization is achieved.

The embodiment of the invention provides a rubidium atomic clock based on a velocity grating spectrum and an implementation method, and the method comprises the steps: enabling a multi-frequency coherent laser source to emit a laser signal containing the velocity grating spectrum, and dividing the laser signal into two paths through a polarization splitting prism; the reflected light beam enters the laser frequency stabilization module to realize laser frequency stabilization; a transmission light beam enters the rubidium bubble through the lens group to interact with rubidium atoms; the photoelectric tube detects a transition spectral line, converts the transition spectral line from an optical signal into an electric signal and transmits the electric signal to the lock-in amplifier for demodulation; the integral amplification module converts the demodulated direct-current voltage into linear increasing voltage and transmits the linear increasing voltage to the crystal oscillator; the crystal oscillator generates an initial microwave signal and generates a microwave signal corresponding to the 87Rb atom through the frequency synthesizer; and the phase frequency modulation module modulates the microwave signal to obtain an error signal and transmits the error signal to the microwave resonant cavity so as to adjust the electromagnetic field according to the error signal to stably lock the rubidium atomic clock. The method is used for achieving the effect of improving the stability of the rubidium atomic clock system.

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 embodiment of the invention provides a chip atomic clock based on a speed grating spectrum and an implementation method. Comprising a multi-frequency coherent laser source, a quarter-wave plate, an atomic gas chamber, a photoelectric detector, a band-pass filter, a microwave modulation and demodulation module, a crystal oscillator, a phase-locked loop module, a bias-tree module, a DC modulation and demodulation module and a servo control module. The multi-frequency coherent laser source is sequentially connected with the quarter-wave plate, the atomic gas chamber, the photoelectric detector and the band-pass filter, the first output end of the band-pass filter is sequentially connected with the microwave modulation and demodulation module, the crystal oscillator and the phase-locked loop module, and meanwhile the microwave modulation and demodulation module is connected with the phase-locked loop module. And the second output end of the band-pass filter is connected with the DC modulation-demodulation module and the servo control module in sequence. And the bias-tree module is connected with the servo control module and the phase-locked loop module and feeds back a coupled signal to the multi-frequency coherent laser source so as to complete whole clock locking. The atomic clock is used for achieving the effect of improving the spectral line signal-to-noise ratio.

The invention, which relates to the thin film thickness control field, discloses a universal and multifunctional polycrystalline diaphragm thickness accurate control system comprising the following components: a data acquisition layer, a data processing layer, a control strategy layer and a man-machine interaction layer. According to the invention, by adopting a plurality of multi-crystal oscillator detection modules with different ranges and frequencies and cooperating with an advanced data acquisition and processing algorithm, high-precision detection of film thickness is realized, and continuity and accuracy of film thickness data in a range switching process are ensured by an intelligent range switching and self-adaptive compensation mechanism, so that the film thickness detection precision is improved. The problems of insufficient precision and data interruption possibly occurring in a traditional film thickness detection method are avoided, meanwhile, the control strategy layer automatically adjusts coating process parameters according to real-time data, PID parameters are continuously optimized through the self-learning function, and the stability and precision of film thickness control are further improved.

The invention provides a light-operated integrated system of a vacuum evaporator, which comprises a first rotating mechanism, a three-stage rotation cooperative control framework is adopted, the first rotating mechanism drives a carrier to revolve, a second rotating piece independently controls a crystal oscillator mechanism to rotate, and a third rotating mechanism regulates and controls a light-operated structure, so that multi-degree-of-freedom motion decoupling is realized; mechanical interference is effectively avoided; a multi-crystal-oscillator alternating detection mechanism is configured, rotation positioning of a crystal oscillator mechanism is driven through a middle rotating shaft, unused crystal oscillators can be automatically switched to be detected, the continuous work period is remarkably prolonged, and the shutdown maintenance frequency is reduced; the optical monitoring function is innovatively integrated, the refractive index / light transmittance parameters of the coating film can be detected in real time through the collaborative design of the rotary light control structure and the probe outer cylinder, a multi-dimensional process monitoring system is formed in combination with the thickness data of the crystal oscillator, and the quality control precision of the film layer is improved by 40% or above.

The invention provides an oscillation circuit loop analysis method based on physical characteristics of a crystal oscillator, which is applied to the technical field of electronic measurement and is used for effectively inhibiting common-mode environmental interference by synchronously acquiring a crystal oscillator signal and an environmental interference signal and utilizing circuit differential operation so as to obtain a differential signal mainly comprising the crystal oscillator signal. Spectral analysis is carried out on the differential signals, actual performance parameters of the crystal oscillator are extracted, and noise is evaluated at the same time. And according to the noise evaluation result, adaptively adjusting the calibration performance parameters of the crystal oscillator to obtain a performance parameter threshold value which better accords with the current environmental noise level. And comparing the actual performance parameter with the adjusted performance parameter threshold, and judging whether the oscillation circuit loop of the crystal oscillator meets the production requirement or not. Therefore, on the premise that the production cost is low, the detection efficiency and the delivery quality of the high-precision electronic measuring instrument are effectively improved.

A performance testing device for a quartz crystal resonator comprises a testing box, an opening is formed in the top of the testing box, the opening is sealed through an upper cover, a transversely-arranged testing plate is installed in the middle of the interior of the testing box, the testing plate is fixedly connected with the testing box through a plurality of supporting springs, and vibration equipment is installed at the bottom of the testing plate. The top of the test plate is provided with a contact pin used for being matched with a quartz crystal resonator, the contact pin is externally connected with a crystal oscillator detection frequency instrument through a wire, a pressing plate is arranged right above the contact pin, the test plate is provided with a vertically arranged guide rod, the pressing plate is transversely and movably sleeved on the guide rod, the guide rod above the pressing plate is provided with a support plate, and the support plate is arranged on the support plate. A pressing bolt matched with the pressing plate is arranged on the supporting plate in a screwed mode, and a reset spring matched with the pressing plate is further arranged on the guide rod below the pressing plate in a sleeved mode. According to the invention, the actual vibration environment can be accurately simulated, so that the influence of vibration at different temperatures on the performance of the quartz crystal resonator can be detected.

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.