• Volume 42,Issue 8,2019 Table of Contents
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    • Design and optimization of a TEG system for electronic equipment

      2019, 42(8):1-5.

      Abstract (995) HTML (0) PDF 6.22 M (900) Comment (0) Favorites

      Abstract:The traditional pavement surface collector power generation methods only consider the temperature factor. In order to optimize the adaptability requirements of traditional road surface heat collecting system for different power consumption electronic instruments, the rutting test is used to study the output efficiency of the heat collecting system under the pressure of the vehicle, and the temperature field distribution inside the asphalt pavement is studied by finite element analysis. The experimental results show that compared with the traditional pavement collecting system methods, the output efficiency of the rutting specimen under the action of 70~80 ℃ is 2.8 times that of static, and the total amount of rutting specimens per unit area collected within 4.5 hours. The energy is 45.46 kJ, which is 6~7 times that of the traditional experimental method. It can be seen that the road surface heat collection experiment needs to consider the road surface with different traffic flow and ambient temperature, and the output energy can meet the electronic measurement equipment with different power consumption requirements.

    • Design of 48 V battery management system for new energy vehicle

      2019, 42(8):6-11.

      Abstract (1044) HTML (0) PDF 10.44 M (1131) Comment (0) Favorites

      Abstract:Nowadays, compared with the environmental pollution caused by traditional fuel vehicles, new energy vehicles have been developed vigorously with the advantage of zero emission. Battery management system (BMS) as one of the core of the new energy vehicles, can monitor the status of battery, improve the utilization rate of the battery, prevent the battery from over-charge and over-discharge, to some extent, prolong the service life of the battery. To design a battery management system hardware circuit with basic functions, this paper uses the XC2267M of Infineon Corporation as the main control chip. The system uses the master-slave structure. The slave control chip is XC886 that completes the collection of the basic information of the battery and passes message through the internal CAN network to the XC2267M, which realizes the functions of information processing and SOC estimation and communicates with other modules and so on. At last, the functions of battery information collection, CAN communication, information storage and battery equalization can be completed.

    • Research on angle measurement error of synchro auto-test system

      2019, 42(8):12-17.

      Abstract (836) HTML (0) PDF 4.97 M (1026) Comment (0) Favorites

      Abstract:Synchro auto-test system is used to measure the rotation angle of angular displacement sensor synchro. The angle measurement error is the main performance parameter of the system. Based on neural network, this paper analyses and compensates the angle measurement error of the automatic test system of the synchro. In this paper, the principle of angle measurement of such a testing system is introduced first. Then, the amplitude mismatch, phase unorthogonality, phase shift between the input signal of SDC conversion chip in the system. The input noise of SDC caused by environmental noise are analyzed respectively, and the error expression is obtained. In this paper, the error is reduced and compensated from the perspective of hardware and software respectively. In the hardware part, the filter phase shift circuit is designed to eliminate high frequency noise. In the software part, The error compensation measure based on BP neural network is proposed. By analysis the results of experiment, the angle measurement accuracy of synchro automatic measurement system using 16Bit converter is 0.3′. After error compensation, the error of the automatic testing system of synchro is less than ±6′, which is met high-precision measurement requirements of the synchro dynamic angle measurement system.

    • Research on power supply design method of well control and lift control system

      2019, 42(8):18-21.

      Abstract (406) HTML (0) PDF 1.64 M (863) Comment (0) Favorites

      Abstract:In view of the cumbersome operation procedure of the pressure device, the logic control of the well control equipment and the clamping device is formed by the combination of hydraulic pressure and automatic control, and the operation flow is automated. However, the protection function of the power supply design is simple, easy to break, and low in reliability. This paper first introduces the design principle of well control and lift control system combining hydraulic and automatic control, and then analyzes the problems of cold backup and hot backup connection modes of dual AC/DC converters in existing power modules. A design scheme of the dual AC/DC converter power supply system is proposed. The research results show that the dual AC/DC converter can enhance the reliability of the power supply module and better solve the problem of continuous power supply of the DC power supply.

    • Design and application of provincial power grid integrated full power collection system

      2019, 42(8):22-27.

      Abstract (852) HTML (0) PDF 7.42 M (2057) Comment (0) Favorites

      Abstract:Energy conservation and loss reduction work is of great significance to the national economy. In order to achieve accurate line loss calculation, collecting and calculating the power supply and sales data of all power equipment is also the way to promote energy saving and loss reduction. This paper designs a provincial power grid integrated full power collection system, which calculates and analyzes the line loss of each voltage level by using the electricity data of the whole network at the same time, and solves the problem that the acquisition system between regions and different voltage levels can’t be interconnected in the existing application. By opening up all voltage levels and regional acquisition systems, the time-sharing, full coverage, and full collection of the gate electricity data within the province′s various power grids can be realized. Through the application in Shandong provincial power grid, it is proved that the system can realize the multi-dimensional statistics of network loss analysis, improve the maintenance efficiency of metering equipment, and promote the adjustment of the main network loss to a reasonable range.

    • The design and implementation of a high power gain cascade microwave amplifier

      2019, 42(8):28-31.

      Abstract (995) HTML (0) PDF 3.22 M (859) Comment (0) Favorites

      Abstract:A high power gain microwave amplifier is expected in the equipment to amplify the small signal. The designation idea and procedure of the amplifier whose power gain more than 100dB are discussed in the thesis. It is about the choice of electronic components, the design of circuits, the layout of PCB of the preamplifier, the intermediate amplifier, the terminal amplifier, etc. Finally, the result of the real amplifier shows that the amplifier has met the requirement of the designation. The amplifier is actually used in the recently implementation of a transmission monitoring equipment.

    • Improvement on application of gray correlation analysis in intelligent transformer area recognition

      2019, 42(8):32-35.

      Abstract (812) HTML (0) PDF 2.15 M (816) Comment (0) Favorites

      Abstract:Distribution area users connection mode is various, circuit topology structure and the characteristics of diversification, there is communication crosstalk between adjacent transformer area, result in inaccurate transformer area recognition, electricity meter reading failure, seriously restricts the transformer area accurate calculation of line loss, and even cause electricity supply and consumption disputes, in order to solve the above problems, ensure the accuracy of transformer area recognition, According to the characteristics of the line voltage of the smart electricity meter in transformer room, a new method that improved grey relational analysis is proposed.The method overcoming the defects of the existing transformer room recognition technology, through analysis line voltage correlation of electricity meter between known and unknown or cross transformer, got rid of a certain degree of subjective judgment, realizing intelligent transformer recognition.The test results show that this method can be used to transformer room recognition accurately under complex environment, and it has great practical value.

    • Theoretical analysis and experimental measurement of the output voltage ripple of high switching frequency Buck converter

      2019, 42(8):36-40.

      Abstract (716) HTML (0) PDF 4.20 M (844) Comment (0) Favorites

      Abstract:Buck converter is commonly used in computer servers and other power supplies. Increasing the switching frequency can reduce the volume of the converter, but the effect of parasitic parameters on the output voltage ripple cannot be ignored. The output voltage ripple of Buck converter is studied in this paper. According to the high frequency equivalent circuit model, the output voltage mathematical expression is solved, the output voltage ripple variations and conditions are obtained, and the conclusion that parasitic parameters affect the value of output voltage ripple is proposed. By designing the experimental prototype of high switching frequency synchronous Buck converter, selecting high bandwidth test equipment and minimum test loop, the experimental measurement of high frequency voltage ripple is actualized, and the correctness of theoretical analysis is verified. This study provides a theoretical basis for the circuit design of Buck converter, and provides relevant experience for high switching frequency experimental measurement.

    • Intelligent anti-myopia sitting posture correction glasses

      2019, 42(8):41-44.

      Abstract (850) HTML (0) PDF 4.07 M (903) Comment (0) Favorites

      Abstract:As it was that the problem of short-sightedness of teenagers and incorrect posture, A kind of intelligent anti-myopia glasses was developed for primary and secondary school students.With the built-in sensor to perceive the data of the user′s reading posture or writing posture, when the user’s sitting posture is not correct, the system had built-in patch LED breathing lights flashing and voice broadcast to remind the user to maintain the correct posture to prevent myopia. During multiple tests, the experiment result indicates that the system built-in EEPROM could store about ten hours data of user sitting poeture. the data could be imported to android mobile phone client through bluetooth which were designed and developmented. the data were parsed to draw the table about the posture of user after analysing datas in order to observe the children situation.

    • Sea channel survey method considering single beam multi beam bathymetric system

      2019, 42(8):45-51.

      Abstract (998) HTML (0) PDF 4.85 M (1082) Comment (0) Favorites

      Abstract:Marine channel measurement is of great significance to ensure the reliable operation of ships. Currently, the system used in anomaly measurement is only one of the time or spatial correlation of measurement errors. Considering the shortcomings of the existing single-beam multi-beam bathymetric system (SBMBBS) and the spatio-temporal correlation of the error matrix, a method of ocean channel measurement is proposed based on the single-beam multi-beam bathymetric system. In this system, the dimension reduction ability of ocean channel measurement and the multi-scale modeling ability of wavelet transform are fully utilized to construct the measurement error system. In the analysis of residual error, it is mainly achieved through control charts. In addition, the sliding window mechanism is effectively used to realize the ocean channel measurement of single-beam multi-beam bathymetry system, from which an on-line SBMBS is obtained. Through the analysis of the measured data and the simulation results, it can be concluded that compared with the BSA algorithm and KLE algorithm, SBMBBS algorithm has more prominent advantages and better measurement performance. The results show that the measurement performance of the online SBMBBS algorithm is very close to that of the SBMBBS algorithm, and requires a very short one-step execution time, which meets the requirements of ocean channel measurement.

    • The design of an air inlet distortion measure dynamic pressure acquisition

      2019, 42(8):52-55.

      Abstract (708) HTML (0) PDF 5.30 M (1545) Comment (0) Favorites

      Abstract:In new aircraft engine subject test, the engine inlet distortion performance test is important, its stability is related to the engine work reliable. Traditional way, multi-channel acquisition of cylinder inlet total pressure by the late data analysis to analyze the dynamic component of the extraction of total pressure, the way large delay and the extraction precision is low. So we design a dynamic component of inlet distortion real-time measurement extraction scheme, the sensor will the front cylinder inlet total pressure. The dynamic component of signal processing, high gain and filtering after the acquisition, and the total pressure signal in synchronization state, ensure data real-time correlation, in order to measure contrast, providing a new method for the amount of engine inlet distortion test. It has been verified by test and flight test, the dynamic pressure data acquisition precision as high as 0.3%, meet the requirement of flight test, and has been successfully applied in a machine of inlet distortion test.

    • Implementation of driver driving safety monitoring system based on Android system

      2019, 42(8):56-60.

      Abstract (434) HTML (0) PDF 7.75 M (983) Comment (0) Favorites

      Abstract:In recent years, traffic accidents have occurred frequently, and fatigue driving has been one of the main causes of traffic accidents, causing huge casualties and property losses. Aiming at the problem of fatigue driving, this paper designs and implements a driver driving safety monitoring system based on Android system. The system consists of a smart car instrument with an Android system and an external camera. Firstly, the facial video of the driver during driving is obtained through the external Android camera. Through the SeetaFace face recognition engine system and the two-level cascading MobileNet-V2 training model, the face detection and facial key point coordinate extraction are realized. Finally, the fatigue algorithm based on face key points is used to realize real-time monitoring of driver fatigue. Experiments were carried out in the case of a simulated cab. The experimental results show that the system is robust to light illumination and glasses, and can greatly reduce the incidence of accidents and ensure driver′s driving. Safety.

    • Research on vehicle license plate recognition technology based on HAAR feature and BP neural network

      2019, 42(8):61-67.

      Abstract (861) HTML (0) PDF 20.01 M (1064) Comment (0) Favorites

      Abstract:License plate recognition technology uses OpenCV(open source computer vision library) computer open source machine vision library to process the image to extract the license plate information contained in the image to achieve the purpose of license plate recognition. By using the HAAR feature, the AdaBoost (Adaptive Boosting) classifier is trained to find the license plate area in the picture; At the same time, the Sobel operator is used for edge detection and other operations to find the license plate area; Finally, the SVM(Support Vector Machine) algorithm is used to finalize the two suspected license plate areas; After the confirmation of the license plate area, character division and other operations are performed to separate characters; The trained back propagation (BP) neural network is used to identify the characters and finally output the license plate information. The research results show that it can effectively identify license plate information and has great practical value.

    • Human behavior analysis based on skeleton model

      2019, 42(8):68-73.

      Abstract (1310) HTML (0) PDF 6.24 M (1190) Comment (0) Favorites

      Abstract:With the application of deep learning in the field of image, the performance of algorithm such as pose estimation and behavior analysis has been significantly improved. We hope to further analyze based on better models and get more intuitive results in the shortest time. The Stacked Hourglass network proposed in 2016 carried out multi-scale and multi-stage training on human keypoints, and regressed 16 pairs of coordinates of keypoints on the MPII dataset with 87.6% average accuracy rate on single GPU of 11G video memory. These keypints were connected into a human body skeleton model. The motion and behavior of the human body are further inferred based on the geometric features of the skeleton model such as weighted angle and tilt angle. The result is classification on human behavior for seven common class actions including standing, sitting, lying and so on. The final average accuracy is 82% and the advantage is to effectively reduce the amount of calculation and processing time.

    • Image classification based on integrated features and multilayer perceptron

      2019, 42(8):74-77.

      Abstract (686) HTML (0) PDF 4.67 M (936) Comment (0) Favorites

      Abstract:Image investigation has become one of the main methods of military investigation. Because of the large amount of data detected in the investigation, how to classify images correctly in the early stage and improve the efficiency of image processing in the later stage has become the focus of research. The features reflected in the image information of different target categories are different. Image classification refers to the distinction of different target categories by features. A feature can not describe the information of an image comprehensively. It combines texture features and gray statistics features into comprehensive features. The multi-layer perceptron has a remarkable ability of learning and reasoning, and it can solve the problem of complex classification. Therefore, a method of image classification based on the combination of image features and multi-layer perceptions is proposed. An image classification system is designed and implemented, using standard image library to conduct experiments. Firstly, the texture features and grayscale features are extracted, and then the selected eigenvalues are combined into eigenvectors for normalization, which is used as the input of the multi-layer perceptron, and the predicted image classes are used as the output of the multi-layer perceptron, and the result of classification is obtained. The classification accuracy is more than 0.8, and the classification system is applied to the test result evaluation system of a certain type of machine. The classification effect is good, which can provide reference for the related application of image processing system.

    • License plate recognition based on regional statistics and BP neural network

      2019, 42(8):78-82.

      Abstract (1013) HTML (0) PDF 5.62 M (1119) Comment (0) Favorites

      Abstract:In order to obtain the character information of the license plate from the license plate image, it is necessary to study the character recognition system. The license plate recognition process is divided into four parts: image preprocessing, license plate location, license plate correction and segmentation, and license plate character recognition. For the first three links, image median filtering, Sobel operator edge detection, mathematical morphology processing, Otsu binarization and Hough transform correction were completed, and a single standard character image was obtained. In the license plate character recognition link, firstly, according to the position of Chinese characters, the template matching algorithm is used to identify Chinese characters. For digital and alphabetic characters, the character images are segmented, and the number of connected regions of each part of the image is obtained to obtain character shape features. And training BP neural network to recognize characters. Finally, a system that can complete the recognition of the license plate characters in the image is obtained.

    • Design and research of home fire alarm system based on Raspberry Pie and computer vision

      2019, 42(8):83-87.

      Abstract (951) HTML (0) PDF 7.54 M (1442) Comment (0) Favorites

      Abstract:At present, the flame recognition technology develops rapidly, which mostly uses the dynamic and static characteristics to identify and segment the flame. But the problems are that recognition error rate is still very high, and the high dependence of the flame recognition algorithm on hardware makes it difficult to apply to residential buildings. In this paper, a home fire alarm system based on Raspberry Pi and computer vision is designed to solve these problems, which takes the Raspberry Pi 3B development board as the hardware infrastructure and combines digital image processing technology. Firstly, traditional flame recognition algorithm was used to segment the flame area, and then SVM algorithm was used to identify and classify the flame, with an accuracy rate of 97%. Finally, a decision was made to decide whether to send warning information to residents. The system has strong expansibility and low cost, which can be widely used in residential buildings.

    • Precision analysis of aerial photogrammetry of the Sirius UAV in plateau mountain area

      2019, 42(8):88-92.

      Abstract (470) HTML (0) PDF 6.02 M (925) Comment (0) Favorites

      Abstract:The office work and field work of traditional UAV aerial photogrammetry in plateau mountains area are complex and inefficient. The Sirius UAV has advanced non-GCPs aerial photogrammetry technology that can quickly acquire high-resolution multivariate data and greatly reduce data processing and field work hours. This paper selects Lishan Village in Yunnan for the aerial photogrammetry area. Digital orthophoto (DOM) and digital surface model (DSM) are obtained by processing aerial photogrammetry data. Measuring the plane coordinates of the detection point from the orthophoto image and measuring the height of the detection point on the digital surface model. The error is obtained by calculation, and then compared with the specification standard to complete the inspection of plane precision and height accuracy. The results show that the mean square error of plane is 0.129m; the maximum error of the elevation accuracy is 0.221m, the minimum error is 0.068m; the mean square error of height is 0.086m. The accuracy of the data meets the requirements of the specification, which proves the feasibility of Sirius UAV non-GCPs aerial photogrammetry technology applied in the plateau mountains area. Through the accuracy analysis of the aerial photogrammetry data of Sirius UAV in Lishan Village, Yunnan, it provides reference and data support for aerial photogrammetry non-GCPs in similar terrain.

    • Airborne transient electromagnetic data acquisition system based on LabVIEW

      2019, 42(8):93-97.

      Abstract (726) HTML (0) PDF 7.88 M (998) Comment (0) Favorites

      Abstract:According to the principle of aero-transient electromagnetic method and its signal characteristics, according to the requirements of long-time continuous acquisition and storage, an airborne transient electromagnetic data acquisition system based on LabVIEW is designed. System hardware platform with NI PXIe-4492 Dynamic signal acquisition card as the core, with Ni pxie-6674t and NI pxi-6682h and other auxiliary board to build; the software part uses LabVIEW to write, using producer/consumer mode, combined with user event processing loop and queue Message processor, realizes the function of data continuous collection, storage, real-time processing and display, and resolves the issue that the transmit and receive clocks are out of sync. Finally, the experiment shows that the system can be collected stably for a long time, and the performance satisfies the design requirements.

    • Research and implementation on algorithm for entry fence detection of shared bicycles

      2019, 42(8):98-103.

      Abstract (607) HTML (0) PDF 4.79 M (969) Comment (0) Favorites

      Abstract:In order to standardize parking, city managers mark parking areas with rectangular solid white lines on the pavement to remind riders to park their bicycles within the fence. A new method uses the K-means clustering principle for fence of shared bicycles is proposed. First, the location data of Gauss distribution are simulated. Second, to get multiple clusters, the data of each location are clustered, and then by means of continuous iteration, the final center of each cluster is determined. Finally, the data of the largest cluster of central points for entry fence detection are analyzed. The accurate rate of entry fence detection is verified by the actual measurement of location data of shared bicycles. The results show that the algorithm can accurately detect whether the shared bicycles enter the fence under the prescribed conditions, accuracy is as high as 80%-100%, and has high practical value.

    • Designing elemental circuit experimental system of power frequency X-ray machine based on virtual instrument technology

      2019, 42(8):104-109.

      Abstract (686) HTML (0) PDF 7.95 M (1108) Comment (0) Favorites

      Abstract:In order to improve the openness of the experimental teaching of power frequency X-ray machine circuit, and to solve the problems of high cost, easy damage and slow update of experimental equipment, research and development of a set of power frequency X-ray machine elemental circuit experiment simulation system for teaching, it can be completed the basic teaching tasks of the power frequency X-ray machine circuit experiment course. Combined with the requirements of the experimental teaching course of the power frequency X-ray machine circuit, taking the typical elemental circuit of the power frequency X-ray machine as an example, the circuit simulation software Multisim simulation experiment circuit, the virtual instrument development software LabVIEW is used to design the experimental system interface, and the interface technology is utilized. The communication connection between the two is realized, and the construction of the experimental system of the power frequency X-ray machine elemental circuit is completed. After the design is completed, the experimental system can simulate the working process of the actual X-ray machine elemental circuit. Students can use this system to carry out X-ray machine rectifier circuit, time-limited circuit, space charge compensation circuit and capacity protection circuit on the basis of theoretical study. Experiments with rotating anode start-up, delay, and protection circuits. The test results show that the experimental system can complete the circuit parameter measurement, circuit signal test and parameter display task in the power frequency X-ray machine unit circuit experiment course. By comparing with the real elemental circuit experiment box, it is proved that the experimental results can reflect the actual X-ray machine tube electrical characteristics. The experimental system effectively increases the hands-on practice opportunities of students, and is highly scalable, which is conducive to the exploratory circuit experiment. Therefore, the virtual instrument technology is used to design and implement the power frequency X-ray machine elemental circuit experiment system. A very effective way not only solves the problem of insufficient experimental equipment, but also provides a new idea for the design and development of other medical imaging equipment circuit experimental instruments.

    • Design of industrial ethernet security monitor

      2019, 42(8):110-114.

      Abstract (730) HTML (0) PDF 3.50 M (688) Comment (0) Favorites

      Abstract:For the industrial network security and virus protection, A special industrial Ethernet security monitor with industrial network layer firewall and depth detection on Modbus TCP is designded for protecting industrial control network. According to the configuration of safety strategy, the monitor can detect unauthorized access, network status and abnormal message, and the critical data of Modbus by using the boundary method, a security monitoring strategy based on process relation is proposed and implemented. Display alarm information and give Suggestions for processing. After testing, the results show that the tools has no influence on the normal industrial control network, the key device can be protected from multiple levels, such as network layer, data flow, key equipment data and process relations.and can effectively detect the exception of industrial control network based on the configuration strategy.

    • Analysis on the accelerated architecture of stateful functional processing based on network resource allocation model

      2019, 42(8):115-118.

      Abstract (300) HTML (0) PDF 2.91 M (640) Comment (0) Favorites

      Abstract:This paper proposes a state acceleration architecture based on programmable hardware, which is built on programmable hardware to realize state management of data plane, so as to realize unified processing of state VNF data transmitted to independent hardware accelerators. Performance analysis results: when more VNF is processed in parallel, it helps to improve the throughput of the SFPA architecture. When four VNF are accelerated in parallel, the hardware acceleration platform will run at full load. After using the resource allocation optimization algorithm, the total amount of SliCE resource consumption in SFPA is reduced. For different VNF, the optimization rate obtained by using this algorithm is also significantly different. When two VNF are accelerated in parallel, the maximum optimization rate obtained is equal to 42%.

    • Experimental analysis on contact temperature rise of high voltage isolating switch contacts in power grid

      2019, 42(8):119-122.

      Abstract (431) HTML (0) PDF 2.05 M (789) Comment (0) Favorites

      Abstract:The maximum temperature rise of GW16-220 isolation switch under different contact conditions is discussed, and the relationship between contact temperature rise and isolation switch parameters is analyzed. The results show that the GW16-220 isolation switch is in a good clamping force range within the clamping force range of 450~600 N, and there is no significant change in contact resistance and temperature rise in this range. Contact temperature increases when load current increases. The fouling degree of contact surface has obvious influence on the steady temperature rise of the isolation switch. The difference between the maximum temperature and the minimum temperature will increase with the increase of the hot spot temperature. Under the static contact head the two sides have similar temperature rise law, and the lower slightly lower than the upper temperature rise.

    • Design and implementation of environmental monitoring car based on Raspberry Pi

      2019, 42(8):123-126.

      Abstract (932) HTML (0) PDF 3.12 M (1161) Comment (0) Favorites

      Abstract:This paper introduces the application of smart car in environmental monitoring and remote video monitoring. Based on core Raspberries Pi, environmental temperature and humidity data obtained from the temperature and humidity sensor, real-time video image data obtained by high-definition cameras, and video image data delivered using WiFi mode to mobile terminal. The mobile terminal sends control instruction through Bluetooth mode. After receiving the instructions, the car is driven by dc motor chip TB6612FNG, thus the remote mobile environment monitoring is realized. The system has the functions of automatic tracking and manual controlling, and automatic tracking can be preseted in the route for the data collection. The experimental results show that the intelligent prototype can exactly collect the expected environmental and video image data and implement the remote environmental monitoring function.

    • Intelligent multi-channel temperature measurement system based on Ntype thermocouple

      2019, 42(8):127-131.

      Abstract (513) HTML (0) PDF 5.17 M (1116) Comment (0) Favorites

      Abstract:Aiming at the demand for temperature test in industrial production such as metallurgy and machinery manufacturing, a high-precision multi-channel temperature measurement system based on N-type thermocouple temperature measurement principle was designed. The system uses STM32 as the control core, ADS1148 as the acquisition chip, and the data transmission through the WiFi processing module Esp8266, so that users can view and monitor data at any distance. At the same time, the least square method of curve fitting is used to calibrate and compensate different sensors, which effectively improves the temperature measurement accuracy and avoids the difficulty of hardware adjustment. The experimental results show that the temperature measurement accuracy of the system can reach ±0.1 ℃, and the volume is small and the performance is reliable. It has a good application prospect in industrial production.

    • Design of 8 channel digital signal timing analysis experimental installation

      2019, 42(8):132-136.

      Abstract (1052) HTML (0) PDF 12.93 M (1216) Comment (0) Favorites

      Abstract:In order to enrich the teaching content of digital logic design experiment and expand the function of digital circuit experiment testing equipment, an 8-channel digital signal timing analysis device is designed based on FPGA. The device has 8-channel Standard Test signal, and the 8-bit trigger word is set by two keys. When the 8-channel input signal meets the trigger condition, the on-chip RAM is enabled. The storage module realizes the storage of 8 digital signals; when the memory is full, the DA conversion is enabled; two analog signals are generated and sent to the X and Y channels of the digital oscilloscope; the display of 8 digital logic signals is realized by using the X-Y display mode of the oscilloscope; it has the function of manual cursor test and can display the corresponding 8 logos through the LED cursor. Edit the signal. The device solves the problem that the oscilloscope can not simultaneously observe the multi-channel logic signal in the process of digital circuit experiment. At the same time, it can be used as an engineering practice case to guide students to design the digital system based on FPGA.

    • Research on risk assessment system of sarcopenia based on AFE4300

      2019, 42(8):137-142.

      Abstract (986) HTML (0) PDF 4.78 M (1519) Comment (0) Favorites

      Abstract:With the change of modern people’s life, more and more middle-aged and elderly people suffer from sarcopenia due to lack of exercise, which leads to higher incidence of muscle atrophy. In order to determine the risk of sarcopenia early, biological impedance method was used to detect the human body. Based on AFE4300, a set of four-electrode human bioelectrical impedance measurement system is designed, which is based on STM32 single chip microcomputer and consists of AFE4300 module, digital grip module, serial port module, power supply module and host computer, etc. Using AFE4300 module to measure the impedance of human limbs, fitting limbs skeletal muscle content, and the use of digital dynamometer to grip strength measurement of the subject, combined with limb skeletal muscle content and grip strength value size, contrast and optimize the sarcopenia’s judgement criteria in the country, risk profile can be divided into three levels: low risk, moderate risk and high risk. Experiments on people over the 18 years old show that the system can reflect the risk of human sarcopenia better.

Editor in chief:Prof. Sun Shenghe

Inauguration:1980

ISSN:1002-7300

CN:11-2175/TN

Domestic postal code:2-369

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