基于虚拟仪器技术的新型焊机检测装置

简单分析了目前电焊机检测设备存在的问题,并利用虚拟仪器技术对现有设备进行了全面的技术改造:采用电流型LEM传感器检测电流和电压信号,利用计算机配合高速数据采集卡采集数据,然后通过软件进行数据处理,根据电流电压有效值定义和有功功率定义等直接获取电焊机参数,在计算机的虚拟仪器面板上同时显示电焊机电流、电压、功率、功率因素、波形畸变率等参数和瞬时信号波形,并对所测信息进行统计处理和其它实用分析。

Design of high-speed signal acquisition system and analysis of signal integrity

The device is used for the test on the fuze detonating time according to the initial velocity of the projectile and the altitude and speed of enemy aircraft flight. For the special requirements of the high-speed signal acquisition in the process, the characteristics of the measured signal are analyzed. The system is investigated in chip selection, signal transmission, signal processing, signal storage, post-production PCB design, etc. The appropriate measures and solutions which affect the integrity and accuracy of the signal in each process are proposed. The rules for the layout of the device and wiring are made. The result show that the measurement values are accurate without loss of data.

On-Board Data Acquisition System for Automatic Shift System of Vehicle

Data acquisition, analysis and calibrating system affiliated with the vehicle is developed for the research on the automatic shift system (ASS). Considering the vehicle’s hard environment such as vibration, high and low temperature, electromagnetic disturbance and so on, the most suitable project is selected. PC104 transfers data with ECU by serial communication and a solid state disk is used as a FLASH ROM. Some techniques including frequency division of data is adopted in the software design in order to ensure the sampling frequency. The analysis and debug software is also contrived according to the characteristic of the ASS. The system plays an important role in the development of the ASS because of the good reliability and practicability in the application.

Discuss on High Speed Data Acquisition and Signal Processing

In order to realize the high speed data acquisition and fast Fourier analysis, the paper put forward a kind of high speed data acquisition and analysis system based on FPGA, the system uses Cyclone series FPGA with high-speed A/D converter, and use the fast Fourier custom analysis nucleation of Altera company, using the standard TCP/IP protocol communication with PC, match up the master machine based on Matlab GUI analysis software. We experiment high speed data acquisition and fast Fourier analysis for a plurality of groups of high frequency analog signals, at the same time the results display on the computer. The experimental results validate the fast Fourier analysis theory, and has realized the low cost, high performance data acquisition and analysis of the complete system design.

Bottleneck Analysis for Data Acquisition in High-Speed Network Traffic Monitoring

The increasing network throughput challenges the current network traffic monitor systems to have compatible high-performance data processing.The design of packet processing systems is guided by the requirements of high packet processing throughput.In this paper,we depict an in-depth research on the related techniques and an implementation of a high-performance data acquisition mechanism.Through the bottleneck analysis with the aid of queuing network model,several performance optimising methods,such as service rate increasing,queue removing and model simplification,are integrated.The experiment results indicate that this approach is capable of reducing the CPU utilization ratio while improving the efficiency of data acquisition in high-speed networks.

Research on a High-Precision Delay Circuit in Data Acquisition Systems

This paper presents a novel precision delay circuit design for high-speed data acquisition systems. Many studies have suggested that various advanced electronic measurement apparatuses require that the delay circuit should have a high precision and a short delay interval. Practically, however, such measurement apparatuses are low in preci- sion and long in delay interval at present. The structure and function of a data acquisition system is introduced first; then the principle of ramp-based precision delay circuits and the digitally programmable delay generator is studied and the precision delay circuit is designed. The authors also demonstrated 8-bit programmable delay circuits with a timing pre- cision of 10 ps. Therefore the programmable precision delay circuit here presented has a higher precision, shorter inter- val and more detectable function than any other precision delay circuit.

Compression techniques of mechanical vibration signals based on optimal sparse representations

This paper presents the result of an experimental study on the compression of mechanical vibration signals. The signals are collected from both rotating and reciprocating machineries by the accelerometers and a data acquisition （DAQ） system. Four optimal sparse representation methods for compression have been considered including the method of frames （ MOF）, best orthogonal basis （ BOB）, matching pursuit （MP） and basis pursuit （BP）. Furthermore, several indicators including compression ratio （CR）, mean square error （MSE）, energy retained （ER） and Kurtosis are taken to evaluate the performance of the above methods. Experimental results show that MP outperforms other three methods.

Fast MR Spectroscopic Imaging Technologies and Data Reconstruction Methods

MRSI plays a more and more important role in clinical application. In this paper,we compare several fast MRSI technologies and data reconstruction methods. For the conventional phase encoding MRSI,the data reconstruction using FFT is simple. But the data acquisition is very time consuming and thus prohibitive in clinical settings. Up to now,the MRSI technologies based on echo-planar, spiral trajectories and sensitivity encoding are the fastest in data acquisition,but their data reconstruction is complex. EPSI reconstruction uses shift of odd and even echoes. Spiral SI uses gridding FFT. SENSE-SI,a new approach to reducing the acquisition time,uses the distinct spatial sensitivities of the individual coil elements to recover the missing encoding information. These improvements in data acquisition and image reconstruction provide a potential value of metabolic imaging as a clinical tool.

Mini-DDL and Its Applications in the Radiation Field Measurement around Accelerators

The variation of the radiation field around accelerator is complex.Only by real-time monitoring can one learn them in detail.The traditional measurement methods have been out of date.The mini-DDL is a specific device designed for such radiation field real-time monitoring.It has huge flash memories and is small in size.It can communicate with the control PC via intranet or RS232 port.So it is suitable to be applied not only in area monitoring but also in temporary monitoring.The radiation field measurements results obtained using the Mini-DDL are introduced in this paper.

Investigate the nonuniformity of low-energy electron beam with large cross-sections

Over the past decades, low-energy electron accelerators have been used worldwide for surface curing and sterilization. The beam nonuniformity is an important parameter of the low-energy electron beam with large cross-sections. A simple and accurate measurement system of nonuniformity for the low-energy electron beam with large cross-sections was developed. The main concept consists in the measurement of nonuniformity, which is realized by using a linear actuator to drive two scanning wires through the beam's cross-sections at a fixed speed. The beam distribution can be obtained by sending/collecting the current signals to/from the Data Acquisition (DAQ) software on a laptop by a USB DAQ card. This device is very convenient for the performance testing of a new accelerator at the manufacturer's site. The distribution of the homemade low voltage electron accelerator EBS-300-50 was measured and evaluated.