Table of Content

25 October 2022, Volume 42 Issue 5

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The Application of the Standing Wave Tube for Underwater Acoustic in Calibration of Vector Hydrophone

CHEN Hong-juan, FEI Teng

2022, 42(5):  1-7.  doi:10.12060/j.issn.1000-7202.2022.05.01

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Application of underwater acoustic tube in low frequency underwater acoustic measurement is wide ranging,it can not only be used to calibrate low frequency underwater acoustic transducer,but also to measure acoustic parameters of underwater acoustic materials and their components.With the development of research on vector hydrophone,the measurement of particle velocity has been studied more and more in standing wave tube for underwater acoustic.Based on the review of the development history of vector hydrophone calibration technology and the current status of research,this paper analyzes the factors affecting the vector hydrophone calibration technology and presents the corresponding research results,at the same time,the corresponding research results are shown,including the high frequency distortion of sensitivity calibration results due to the positioning mode of reference acoustic pressure hydrophone and vector hydrophone under test,and the low frequency distortion of sensitivity calibration results due to the influence of vector hydrophone suspension structure when using comparative calibration method in the standing wave tube.In addition,the future development direction of vector hydrophone technology is prospected.

Research on Development Status and Key Technologies of Digital Metrology

LI Ang, HE Wei

2022, 42(5):  8-12.  doi:10.12060/j.issn.1000-7202.2022.05.02

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The metrology industry provides means for the measurement of data in all walks of life and ensures the correctness of the data.In todays wave of digitalization,in order to better play the important role of the metrology industry,it is necessary to carry out a major transformation from traditional metrology to digital era metrology,that is,to complete the digital transformation of the metrology industry,referred to as digital metrology.The core of the digital metrology is that on the basis of the corresponding digital technology,to realize the digitization of the metrology data and the test reports and calibration certificates,make the standards of calibration procedures machine-readable,obtain the digital twins of the measurement standard devices,make the calibration verification operations automatic and intelligent,build the digital dissemination traceability chain,and transmit measuring trust and value unification in the digital way.In the world,authoritative institutions have issued guiding documents for the realization of digital metrology,leading the trend of global digital metrology reform.

Antenna Planar Near-field Measurement System with Frequency 110 GHz~170 GHz

LIU Xing-xun, CHENG Xian-you, HUANG Cheng-zu

2022, 42(5):  13-16.  doi:10.12060/j.issn.1000-7202.2022.05.03

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In order to meet the requirement of antenna calibration accurately with frequency range (110~170)GHz,An antenna plane near-field measurement system based on robot automatic scanning is designed.The system is composed of a vector network analyzer,spread spectrum modules,mechanical arm scanning frame,small optical platform and a scanning probe etc.Parameters of measurement setting and scanning trajectory control of manipulator are realized by testing software.The amplitudes and phases of test points on the scanning surface are collected by software,which is calculated using Fourier near-far field transformation algorithm.Then the antenna gain directivity pattern is obtained.A standard gain horn as an antenna under test is tested by the antenna planar near-field measurement system.The results are very consistent with those measured in far-field method and the maximum deviation of the main lobe pattern is 0.25 dB.

Study of Ground Calibration Test Equipment for Aerospace Solar Cells

WEN Tian-cheng, ZHANG Shu-feng, LIU Min, LU Jia-lin, WANG Kai, DENG Xing-liang, TANG You-dong

2022, 42(5):  17-22.  doi:10.12060/j.issn.1000-7202.2022.05.04

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The traditional standard solar cell calibration methods are divided into high-altitude calibration and ground calibration,and the ground calibration method has been included in the ISO.Ground calibration is widely used nowadays because it is easy to operate and the calibration results are relatively accurate.Whether the results of solar cell calibration are accurate or not is of great significance to the design of the spacecraft power system attitude sensitive period and ground environment simulation.The ground calibration method of solar cells is discussed in this paper,a portable and high accuracy ground calibration test equipment is developed,based on the theories of ground calibration method in the national standard,including collimation holes,solar cell tray,solar tracker,and other calibration devices,to simplify the ground calibration process,which is of great significance to the ground calibration of aerospace solar cells.

Calibration Device for Key Parameters of VUV Detector

SUN Guang-wei, DU Ji-dong, LI Shi-wei, DENG Pei, CHENG Qian, HUANG Liang, ZHOU Guo-ao, YANG Hai-sheng

2022, 42(5):  23-28.  doi:10.12060/j.issn.1000-7202.2022.05.05

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At present,with the rapid development of VUV space detection technology,VUV load is applied more and more widely,and the characteristic calibration of the VUV detector,the core component of which is becoming more and more important.Aiming at the lack of the ability of key parameters calibration of domestic VUV detector,a calibration device of key parameters for VUV detector was developed to realize the calibration of spectral response rate,linearity and other parameters.The calibration method of spectral response rate and linearity of VUV detector was described.The hardware composition,calibration method and software function of the calibration device were introduced,and the measurement uncertainty was evaluated.The test results show that the calibration device can calibrate the main parameters of the VUV detector,and the calibration results are accurate and effective.

Global Navigation Satellite Systems (GNSS)Active Antenna Noise Temperature Measuring Device

CAOYue, HU Yu, YANG Han-xu, ZHANG Jin-ling, ZHAI Hong

2022, 42(5):  29-33.  doi:10.12060/j.issn.1000-7202.2022.05.06

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The noise temperature of satellite navigation active receiving antenna is one of the key technical indexes of navigation receiver.In order to solve the problem that the overall noise temperature of the satellite navigation active antenna cannot be measured,two surface type noise sources are developed.The surface type noise source is mainly composed of radiator,radiator physical temperature control and temperature measurement instrument.The two surface type noise sources provide the high and low standard noise temperature in L band and S band.The noise temperature of active receiving antenna is measured by Y-Factor method.The noise temperature of a satellite navigation active antenna is measured.In the frequency range of (1.19~1.29) GHz,the noise temperature measurement result is 206 K at the center frequency of 1.24 GHz.However,the noise temperature measurement result is greater than 4 000 K at the frequency of 1.266 GHz,which indicates that there are design problems or other problems between the antenna and the filter,and between the filter and the amplifier,reflecting the necessity of measuring the noise temperature of the active antenna.

A Method for Generate Ultra-wide Rate Test Pattern

JIA Mao-hua, TONG Qiong, KONG Ling-lei

2022, 42(5):  34-37.  doi:10.12060/j.issn.1000-7202.2022.05.07

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With the development of modern technology,the working rate of information transmission system is constantly expanding,so Bit Error Rate Tester must have the ability of generate Ultra-wide rate test pattern for reliability and stability evaluation.The article propose a method for generate Ultra-wide rate test pattern,it break the Ultra-wide rate test pattern of 50 Mb/s～60 Gb/s down into four pieces,and use high-speed switch to choose output pattern.In the article,we built a test system based on FPGA(field-programmable gate array) + multi MUX(multiplexer) architecture,by decompose the whole range of working rate,finally generate a Ultra-wide rate test pattern of 50 Mb/s～60 Gb/s.

Design and Implementation of Semiconductor Minority Carrier Lifetime Measurement System based on High Frequency Photoconductivity Method

ZHAO Zhao, GAO Zi-xing, LI Jie

2022, 42(5):  38-43.  doi:10.12060/j.issn.1000-7202.2022.05.08

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Based on the basic principle of minority carrier lifetime measurement of semiconductor by high frequency photoconductive attenuation method,a minority carrier lifetime measurement system is designed,and the signal processing system is improved on the basis of the diode detection circuit.Compared with the traditional diode detection circuit,the feedback principle of the operational amplifier eliminates the error caused by the voltage drop of the detector diode.At the same time,the effect of the voltage swing rate of the operational amplifier is reduced by the diode embedding effect,which further improves the detection ability of the measurement system.In addition,the feasibility of the detection circuit is verified by experiments,which effectively improves the accuracy of the measurement system.

Deep Learning-based Foggy Weather Monitoring via Wireless Communication Link

CHENG Qian, WU Zhong-dong, ZHENG Li, MIN Jie

2022, 42(5):  44-51.  doi:10.12060/j.issn.1000-7202.2022.05.09

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In order to monitor foggy weather at low cost and high temporal and spatial resolution,a deep learning-based foggy weather monitoring via wireless communication method was proposed in this paper.Since different concentrations of foggy weather in the channel leave different features in the signal,this paper collects radio signals under four different concentrations of foggy weather to establish the foggy weather monitoring dataset.By introducing an attention mechanism in the conventional ResNet50 network and performing feature fusion,an improved A-ResNet50 model is obtained.The A-ResNet50 network is used to extract the features of different concentrations of foggy weather left in the received signals,and to classify and identify four types of different concentrations of foggy weather for the purpose of monitoring foggy weather.The proposed method was validated on the dataset established in this paper,and compared with other traditional classification algorithms,the network model proposed in this paper has the best performance.The final recognition accuracy reached 86.18 %, and the result proved the feasibility and effectiveness of the method.

Research on Digital Fault Arc Identification Scheme based on AI+ Neural Network

YANG Tu-qiang

2022, 42(5):  52-56.  doi:10.12060/j.issn.1000-7202.2022.05.10

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With the improvement of power electronic technology,the characteristics of line fault arc become more complex,and the traditional fault arc identification method has been unable to cope with the new power system.Compared with the traditional fault arc identification scheme,the generation type and new detection technology of fault arc are studied,a digital fault arc recognition scheme based on AI+neural network is proposed,which is based on typical time-domain and frequency-domain characteristics such as harmonic factor,total harmonic distortion rate,current zero rest time,current change rate,current periodicity,etc.In this scheme,the regression algorithm vector machine is used to classify the feature map,and the convolution neural network is implemented through three steps of forward transmission operation,reverse transmission operation and iterative regression operation.Frequent iterative regression is used to obtain the best feature recognition map.This paper takes the fault arc identification of dimmer as an example to verify the fault identification scheme.The results show that this scheme can achieve more efficient,more accurate and more stable fault arc identification.

Long Short Term Memory Neural Network (LSTM) based on Clock Difference Forecasting Algorithm

WANG Rui, GONG Jian-jun, DU Hong-qiang, WU Wen-jun

2022, 42(5):  57-62.  doi:10.12060/j.issn.1000-7202.2022.05.11

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Atomic clock clock difference forecasting has an important role in atomic time calculation and atomic clock frequency harnessing.In this paper,we use hydrogen and cesium clocks as samples to reduce the effects of long-term atomic clock internal noise and atomic clock drift on the clock difference prediction by constructing LSTM clock difference prediction models,and compare the prediction lengths of 72 h,240 h and 720h with linear polynomial model,gray model and Kalman model respectively.The prediction errors are compared with the linear polynomial model,the gray model and the Kalman model.The analysis shows that for forecast lengths above 240 h,the advantage of long-term dependence of LSTM modeling is realized,and higher forecast accuracy can be obtained compared with the other three types of models.

Design and Implementation of Traceability System based on Optical Fiber Two-way Time Comparison

XIE Yong, ZHAO Da-yong, YUAN Yuan, YANG Jun

2022, 42(5):  63-68.  doi:10.12060/j.issn.1000-7202.2022.05.12

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In order to meet the remote and high-precision traceability requirements of precision atomic time scale,a traceability system based on optical fiber two-way time comparison is designed and implemented.Combined with the advantages of high precision of optical fiber two-way time comparison,the local atomic time scale can be traced to the remote UTC standard time.By adopting the redundant backup mechanism of main and standby equipment,the reliability of the system is improved.The test results show that based on the technical means of optical fiber two-way time comparison,the traceability effect with the standard UTC is better than 1 ns and the daily frequency stability is within 5E-15.At the same time,the time synchronization technology of the main and standby channels realizes that the time difference of the main and standby channels is better than 0.3 ns.

Non-magnetic Thermostat Control System for Cesium Optical-pumping Magnetometer

XIE Yin, CHENG Zhi-yong, LI Xiao-fang, WANG Ling, ZHANG Fan

2022, 42(5):  69-72.  doi:10.12060/j.issn.1000-7202.2022.05.13

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Aiming at the requirement of high temperature stability and non-magnetic interference in the atomic gas cell of the cesium optical-pumping magnetometer,a non-magnetic thermostat control system for the cesium optical-pumping magnetometer is designed.The system mainly includes a non-magnetic heating chip and a non-magnetic thermostat control circuit.The non-magnetic heating chip adopts the double-layer symmetrical four-wire structure of MEMS technology,which can effectively suppress the magnetic field generated by the current;The non-magnetic thermostat control circuit uses AC heating to further reduce the constant magnetic field interference.With the field programmable gate array as the core,the direct digital frequency synthesis technology is used to generate high-frequency heating signals,and then the non-magnetic thermostat control is performed through power amplification to reduce the circuit hardware resource.The test results show that the temperature control stability of the gas cell can reach 0.02 ℃,which meets the performance requirements of the optical-pumping magnetometer.

High Temporal Resolution Transient Thermoreflectance Microscope

LIU Yan, ZHAI Yu-wei, JING Xiao-dong, DING Li-qiang, REN Yu-long, WU Ai-hua

2022, 42(5):  73-78.  doi:10.12060/j.issn.1000-7202.2022.05.14

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Transient thermoreflectance microscopy is capable of capturing surface temperature distribution of electronic devices with both high temporal resolution and high spatial resolution,and is widely used in thermal characterization of high-power devices like GaN HEMT.A setup of high temporal resolution transient thermoreflectance microscope was developed,adopting short pulsed illumination to capture the image of DUTs surface at specific moments.Temporal resolution up to 1 μs was achieved.Experiments were taken on micro-resistor to observe the transient thermal response to pulsed drive with 10 μs duration.Thermal images of the resistor at different moments were captured,providing details of the heating and cooling process.[JP2]The rising and falling time of the temperature of the micro-resistor were (2~3) μs,which confirmed the claimed temporal resolution.