Based on the characteristics of the maglev vehicle,the paper presents a new way of positioning used in maglev vehicle. Based on the technology of coding a group of magnetically controlled switches,we have designed this positioning device by using the structure of the combination of DSP and FPGA. The experience results show that the positioning device can realize the function of positioning,with the advantages of low cost,high reliability and low maintenance costs.
This article introduces a implementation method which is improved upon IEEE 1588 protocol.The ZigBee network bandwidth costs are reduced by simplifying the follow-up messages in IEEE 1588 protocol.Meanwhile,the initiator of the synchronization is changed from the master node to the slave node to adapt the real-time join and leave feature of ZigBee node.The experiment proved that this algorithm is suitable for high precision time synchronization.
in order to obtain the emission performance of SC containing barium tungsten cathode heat,using liquid-solid doping,doped tungsten powder reduction,isostatic pressing,sintering temperature,impregnation emitting substance such as technology,preparation of tungsten matrix barium tungsten cathode.On the cathode emission performance test results show,in the cathode temperature were 950℃,1050 ℃,1100 ℃,pulse emission current density were 53.6 A/cm 2 、 65.7 A/cm 2 、 79 A/cm 2 The analysis thinks,as a result of scandium oxide is covered uniformly on the surface of tungsten particles,scandium oxide with tungsten contact surface increases,make the scandium oxide and tungsten binding force is increased,therefore the cathode has excellent uniformity of hot electron emission,high ion bombardment resistance ability.
This paper presents principles and design of the comb generator. The comb generator can generate signals whose phase noise below -108 dBc,1 kHz in X-band.
Introduced the second west to east gas pipeline and the basic situation,technological process,introduces the PLC,station control machine,routers,switches and other control equipment in the project application,and analysis of Ethernet,ControlNet network,discusses the control system composition and function.
In order to solve the problem that the old solitary man can't get the treatment in time when they fall ill suddenly,the system use the STM32W108 radio frequency chip as the core processor,which is used to monitor the heart rate and the fall incident.The system extracts the heart rate based on the QRS wave in ECG signal while determines whether the elderly have a fall depended on the analysis on the signal from the three axis acceleration sensor combined with the change of motion state and the attitude features.The device has been proved to be reliable and practical with the simulative test.
Eutectic is an important technology of micro-electronics assembly. It is more and more used in hybrid circuit.This paper describes briefly Principle of eutectic,and analyzes factors influencing on chip eutectic technology of thin film substrate.It uses Ti/Ni/Au film and AuSn solders, also designs fixture and studies chip eutectic technology of thin film substrate by importing nitrogen and hydrogen shielding gas in vacuum atmosphere.The test suggests void is controlled effectively below 10% when Au thickness of substrate metallization is 1.5μm, pressure is 2kPa,bonding temperature is 330℃ and bonding time is 30s. Reliablity of shear strength and contact resistance of eutectic samples were tested after 150℃ high temperature storage and -65 ℃-150℃ temperature cycling. After reliablity test, shear strength of samples can meet the requirement of GJB548B-2005 and the change of contact resistance is less than 5%.
Introduce an ultrasonic obstacle distance detection and voice broadcast system based on ultrasonic sensor and Iflytek TTS voice module.With the use of single-chip microprocessor system,the target obstacle could be detected by the ultrasonic transceiver transducer.After temperature compensation,the distance away from target obstacle was displayed and broadcasted by LCD and TTS module.The detailed system hardware design and software flow chart were presented.This system was simple,stable,convenient,fast response and also with the feature of intelligent voice broadcast.It could be used to situations such as blind navigation,motor vehicle parking or illegal intrusion detection of specific area.
Distributed power supply has investment province, flexibility, compatibility with the environment and other characteristics, is the realization of the utilization of new energy sources. In order to reduce the adverse effects of distributed power and make the photovoltaic generating unit, a wind power generation unit, load, energy storage device and control apparatus consisting of small power - micro grid, micro network satisfies the power supply reliability and quality, safety. Micro electric network control technology is stable and reliable operation of micro power system key technology. Based on this, this paper focuses on the introduction of wind and photovoltaic distributed power generation technology, and based on the distributed power control technology of micro net management. To explore the field of research and development prospects.
The article gives a brief introduction about the way of interferometer direction finding,analyses the principle of direction findingd and the reason of the error comes in to being.The purpose is that to solve the problem of the error come into being the way of interferometer direction finding.It adopts the ways about antenna's change linked and rectify parameter's added. By means of above ways that gains a fairly good result and solves the error.
This article based on the decimal sub-frequency phase-locked loop HMC704LP4 to the design of an X band frequency synthesizer with low phase noise,spurious,low,the characteristic of small volume. In view of the requirements of the design scheme,design process,given the design parameters,key indicators of simulation,and gives test curve.
Aimed at the problems on the non-linearity and hysteresis of pressure sensor used in bearing load-shear test machine of bridge which the non-linearity of capacitive pressure sensor signal and the hysteresis problem was analyzed. Using the least square method to correct the non-linearity of sensor output signal and using function correction method for hysteresis compensation. The results show that the method can correct the non-linearity and hysteresis.
Synchronous Serial Interface (SSI) has such advantages as high transfer speed, simple connection, excellent noise proof feature and it is widely used in industrial control and other fields. However, SSI is not provided in most industrial control computers and the extended SSI cards are expensive and hard to find on the mark. Based on the SSI module of SSI208P and digital input/output card, a low cost implementation of multi SSI photoelectric encoder high speed data acquisition by industrial control computer is introduced. Hardware and software are given in detail.
A smart car control system based on the electromagnetic sensors was introduced.The system employs Freescale XS series 16 bit MCU MC9S12XS128 as its main controller and an array of electromagnetic sensors for recognizing the path information.MC9S12XS128 energizes the server to steer and control the speed of the DC electric motor according to the analysis of the path and speed information from sensors.Consequently,this intelligent vehicle can track the black-guide-line automatically and move forward following the line quickly and smoothly.Experimental results show that the design of system is reliable and the smart car works well.
This paper mainly discusses the m odel of chaff motion after the aircraft launching the chaff,that the atmospheric density,wind speed,aircraft wake vortices and their properties with the impact of chaff is taken into account to establish the model of chaff motion basing on the atmospheric environment .so the chaff-cloud's velocity, displacement and volume can have a quantitative description,Radar scattering section that relates it tightly is also involved.
NiosII embedded processor with its flexible design advantages in embedded are widely used in the field. This paper describes a NiosII based liquid crystal display screen scroll screen display control module, gives the hardware schematic diagram and software code. The scheme for NiosII system development is had draw lessons from a meaning.
In practical engineering,when system design and processing out,the circuit structure have been identified.but there will be a variety of problems in the debugging process,which requires that engineers have a lot of debugging experience.We take the debugging of the C-band receiver,for example,and proposed to eliminate the crosstalk of the self-excited instance of the application.A good solution to the RF high gain amplifier due to the entry of external crosstalk and the self-excited,in the end we making the system work normal and stable,some experience,and learn for engineering practice.
A CMOS Oscillator is proposed in this paper,which can be used in a low-EMI filter-less Class D audio amplifier. This oscillator is made up of a comparator with internal positive feedback and used for conventional PWM modulation of audio signal. We can get a high resolution CMOS RC oscillator using this structure,which could be less independent of the voltage and temperature variation. The simulation results shows that this RC oscillator have a more stable frequency.
This paper begins from hardware design,then introduces the independent design of WSN nodes whose core is STM32W108.Based on the design of hardware and adopted a weighted centroid localization algorithm which based on RSSI,we realize the localization of nodes.The algorithm was realized by combined RSSI ranging with centroid localization algorithm,and reflected the force of constraint of different anchor nodes to unknown nodes by using the RSSI as weight coefficient.The test results show that the weighted centroid localization algorithm based on RSSI has higher localization accuracy with less communication cost and realizes easily.
In order to realize the management of wireless sesor network,we put forword the design of WSN gateway based on the Android platform.The Gateway realizes the data transmission between WSN central node and the Android platform through Bluetooth Serial Port,and realizes the management of WSN node information management in the Android platform,then realizes Internet acess through Android network resource,finally realizes the transparent data transmission between WSN and the Internet and completes remote and real-time monitoring of wireliess nodes' datas.
