中国航空工业集团公司 北京长城计量测试技术研究所

正DMP8000高精度触摸屏测量仪●可实现力值和扭矩值的测量与标定●12～20虚拟通道可选,可10点线性修正●可存储300个测量数据,多种单位可选●准确度:0.005%●采样时间:0～50次/秒(可选)●具有串行数据输出和打印接口●每个通道都具有超上限声光报警功能●重量:2.86kg     

欧米茄井下智能仪器公司 展位号：W1105HH309A四通道数据记录温度计

HH309A四通道数据记录温度计是一款带有强大的数据记录器的小型4输入温度计。该装置可按编程的时间间隔为每个通道存储多达16000条记录。     

如何选择示波器

示波器从带宽、采样速率、屏幕刷新率、存储深度、多少通道以及模拟还是数字示波器等因数进行选择。     

可扩展级联式机载数据采集系统设计

为实时采集飞行器舱体各部位的振动、冲击、压力等多路信号,设计一种通道可自由扩展的级联式机载数据采集系统。以FPGA为核心控制器设计基础模块和传感器采集模块,通过将多个采集模块堆叠级联的方式实现对任意通道的扩展。采集模块内置信号调理和采集电路、存储和控制电路,采集数据按通道编帧后分层存储。基础模块通过级联总线发送触发或读数指令,控制采集进程,并利用LVDS电缆将数据上传到计算机进行波形分析。实际测试表明:该系统能根据应用需求灵活扩展通道数量,同步采集时单通道采样率≥300 k S/s,电压转换误差0.2%,具备体积小、易维护等特点。     

高分辨同步数据采集处理系统设计

设计了一种Delta-Sigma技术的24位高分辨率同步数据采集系统.该系统具有2个差分模拟输入通道,并具备扩展到8个差分模拟输入通道的能力,具有高速、高分辨率、低功耗三种工作模式.板载DSP完成数据的缓冲,并通过RS232/USB2.0接口与上位机通信,接收上位机的控制命令,向上位机发送采样转换数据.VB6.0开发的Windows数据采集处理程序具备了诸如采样参数设定、波形和数据显示、滤波、信号参数测量和频谱分析等功能,构成了一个功能完备的24位分辨率的同步数据采集处理系统.     

新型旋浆式流速流量仪的研制

系统以AT89C51单片机为核心控制器,采用先进电子元器件为基础,运用新的设计思想研制而成.该仪器具有瞬时测量流量及流速、存储数据量大(100个存储通道)、汉化显示等优点.应用中断方式采集数据,实现了数据的实时检测及处理的要求,提高了采集数据的频率.该设备通过试验标定,其性能稳定,准确度高.     

谈RAMASA WR-DA7小型数字录音调音台的功能和使用（五）

数字式调音台与模拟调音台相比，最大的优势就在于它具有强大的记忆储存功能。DA7有三个数据库，这三个库是：channel library(通道库)、Equalizer library(均衡器库)、Dynamics library(动态库)。每一个数据库中都有50个存储器，库窗口显示当前所选通道的当前设置。通道信息显示在窗口的左侧，库数据显示在窗口的右侧。在这个窗口中，使用者设置当前通道的参数，也可以在这些窗口中存储数据或调出数据。     

数字存储示波器时基失真与采样抖动的评价研究

提出了数字存储示波器采样间隔抖动和采样时基失真的一种时域评价方法.通过两段正弦波形段的滑动拟合结果,使用两者间对应点相位上的差异,实现了采样间隔的测量,获得其抖动波形和时基失真的测量结果.在一组仿真数据上进行了实验验证,并揭示了量化误差对抖动评价影响的规律,以及抖动测量结果的周期性变化规律.在数字存储示波器的实测数据上进行了实验验证,获得了有效的抖动波形结果.该方法可以用来观察和比较采样间隔的抖动以及采样时基失真特性.     

数据库技术在直升机飞参处理中的应用

针对某直升机飞行参数数量多、类型复杂、带宽各异的特点,本文设计了可编程的数据采集和处理系统,可自动分配数据采样通道和采样率,并按照通道分配自动处理数据.解决了一套飞行参数处理系统支持多机型、多参数的难题.     

虚拟现实中多通道信息呈现方式的认知负荷定量研究

目的 针对虚拟现实体验系统中的不同信息呈现方式,对使用者交互效率影响难以确定及量化的问题,进行定量研究。方法 通过搭建虚拟现实场景,以信息呈现通道的类别与数量作为变量,展开跟踪–检测响应双任务实验;通过记录任务行为数据中的跟踪误差和响应时间,以及生理数据中的瞳孔直径大小,分析并讨论在不同通道刺激影响因素下的实验中,任务绩效及眼动生理反应变化规律;同时结合主观负荷评价数据,建立了基于BP神经网络的多通道认知负荷模型,以认知负荷作为交互效率的综合评价指标,量化任务执行效率。结果 信息呈现的通道类别及其数量对任务效率均有显著的影响。结论 信息呈现通道数量与任务绩效及生理反应呈一定程度的正相关;多个任务使用相同通道呈现信息会损害所有任务的绩效,增加认知负荷。模型输出的负荷值与主观认知负荷评估值吻合较好,相对误差为8.2%,验证了其有效性。     

Alternate video broadcasting scheme for popular videos

A video segment broadcasting scheme can reduce server and network bandwidth by periodically broadcasting popular videos that are most likely demanded by clients, instead of responding to each client requests. When video segments broadcast on a channel, in general, alternate broadcasting schemes periodically transmit all segments on a given channel with the same transmission period, which reduces the transmission efficiency of stream channels and requires sufficient client storage space for video segments broadcast on simultaneous channels. The author proposed a novel alternate video broadcast scheme, a delayed buffering broadcast that requires lower server bandwidth and client buffer space compared with those of previous approaches. In addition, the study provides an analytical analysis of the scheme, including a lower bound on the video segment transmission rate for any alternate broadcast scheme. It also derives an upper bound on its storage requirements from the client side. Using the performance study of the proposed scheme and simulation results, the author establishes that the proposed scheme uses fewer server channels and storage resources than previously reported alternate video broadcast schemes for any given client waiting time.     

应用于雷达系统的双路高速数据采集存储系统设计

介绍了一种用于对雷达回波I/Q信号进行双路高速采集与数据存储的系统,采样速率为200MHz,分辨率为12位,存储深度为4GB.该系统采用FPGA作为主控制器,ADS62P29作为高速数据转换器,K9K8G08U0M作为大容量数据存储器,通过USB实现系统与计算机之间的通信.利用Cadence软件和VHDL语言完成了系统设计、软件仿真及关键信号的完整性仿真.测试结果表明,ADC的有效位数可达10.69,输入信号为80 MHz的正弦信号时,两路ADC信号之间的相干系数达到0.998 4,可满足雷达系统对回波信号进行高精度相位测量的要求.     

A/D Controller for Acquisitions of Signals with Different Sampling Periods

Efficient data acquisitions from analog signals of very different bandwidths require that each analog signal be sampled at a different rate. This paper proposes an A/D controller which has been implemented on an Analogic 5800 data acquisition system. The host computer is a PDP 11/45 with a DR11-C interface (see Fig. 1). Essentially, this programmable controller sorts out the sequencing of eight different analog channels. The sampling rate of each channel is independently set by software from 10 to 255 ps in I-its increments. Once the controller is programmed, it will control the A/D itself. The host computer programs the controller according to the user's instructions. The sampling rate of each analog channel may be independently set by software from 10 to 250 ps. Then the controller sets out the appropriate sequencing of the data collections on the analog channels, sorts out conflicts, and sees that information is stored properly in the host computer.     

Uniform time-sampling Fourier transform spectroscopy

We show that uniform time sampling of both the reference and the target channels in a continuous scanning Fourier transform spectrometer is a simple and versatile way of extending the Nyquist limit shorter than the wavelength of the reference channel. We also discuss the benefits of recording the reference channel when intensity calibrating the target data.     

Comprehensive asynchronous symmetric rendezvous algorithm in cognitive radio networks

Spectrum has become a scant quantity with recent upsurge in the field of wireless communication. Cognitive radio network (CRN) alleviates the overgrowing spectrum scarcity and underutilization problem by adequately sharing the frequency bands between licensed and unlicensed users. CRN allows unlicensed users or secondary users (SUs) to opportunistically utilize the free portion of the spectrum allocated to the licensed users or primary users. The fundamental process in the formation of CRN is the rendezvous process where SUs meet on commonly available channels and establish reliable links for effective communication. Existing rendezvous solutions based on the assumption of a common control channel (CCC) among the SUs are infeasible and less efficient in the dynamic environment of CRNs. Therefore, channel hopping (CH) technique without CCC support, often referred to as blind rendezvous, is usually employed for accomplishing the rendezvous between SUs. This paper presents a comprehensive asynchronous symmetric rendezvous (CASR) algorithm that does not require time synchronization and guarantees rendezvous of SUs in finite time. CASR algorithm exploits the MAC address of SU as the unique identifier (ID) and generates CH sequence based on the dynamic manipulation of ID according to the number of available communication channels. Leveraging the unique ID of each SU, CASR algorithm succeeded in rendezvous guarantee while perpetuating a good time to rendezvous. The efficiency of CASR algorithm is estimated theoretically and verified through various simulation experiments. Simulation results affirm that CASR algorithm performs better in terms of average time-to-rendezvous as compared with existing rendezvous algorithms.     

时空双通道机器人电触觉临场感再现技术研究

时空双通道机器人电触觉临场感再现将时间通道的刺激电流控制信号和空间通道的触觉信息合成为音波文件,经计算机声卡播放后输出的双声道音波信号分别对应时空两个通道的控制信号,信号经进一步处理后提供触觉再现所需的刺激电流并选通相应触点。该技术对于消除电触觉突发刺痛感和改善时间适应性具有重要价值。     

一种通用多通道高频相控发射和采集系统

声呐系统性能检测需要一种多通道可控相位信号和多通道大容量高速数据采集系统。通过多种高速数据采集和信号发射方案的对比,选用基于图形化编程语言LabVIEW和相应的硬件设备,设计、研制了一种32通道发射和128通道高速数据采集系统,用于多数声呐系统的性能检测。发射系统利用直接数字合成技术,生成可以单独调节相位的32通道正弦信号;采集系统采用分块读取减少缓冲区数据占用的方式,实现有限数据采集,并采用减少显示图形更新次数、使用DAQmx配置记录函数等方法,实现连续数据采集。测试结果表明,系统实现在采样率为2 MHz时,128通道中每通道1 300 000点的有限数据采集,以及采样率最高为0.7 MHz的128通道的连续数据采集。利用该系统对高分辨率测深侧扫声呐的发射信号进行检测,发射信号正常,系统工作良好。     

基于CAN总线的数字量变送器的设计

设计了CAN总线技术的数字量变送器,用于数字信号的采集和传输.重点介绍了系统硬件电路设计及其实现,并且给出了一种通过CAN总线进行信号传输的方案.本设计采用C 8051F 060单片机作为中心控制单元,当多路数字信号中的某路信号发生变化时,单片机对其状态变化进行记录,然后通过局域网CAN总线将数据发送出去.测试结果表明,该设计能很好地完成数字量信号的采集存储和传输,具有可靠性、实时性和灵活性等优点.目前,该设计已成功运用于某大型车载故障诊断项目.     

Massive Files Prefetching Model Based on LSTM Neural Network with Cache Transaction Strategy

In distributed storage systems, file access efficiency has an important impact on the real-time nature of information forensics. As a popular approach to improve file accessing efficiency, prefetching model can fetches data before it is needed according to the file access pattern, which can reduce the I/O waiting time and increase the system concurrency. However, prefetching model needs to mine the degree of association between files to ensure the accuracy of prefetching. In the massive small file situation, the sheer volume of files poses a challenge to the efficiency and accuracy of relevance mining. In this paper, we propose a massive files prefetching model based on LSTM neural network with cache transaction strategy to improve file access efficiency. Firstly, we propose a file clustering algorithm based on temporal locality and spatial locality to reduce the computational complexity. Secondly, we propose a definition of cache transaction according to files occurrence in cache instead of time-offset distance based methods to extract file block feature accurately. Lastly, we innovatively propose a file access prediction algorithm based on LSTM neural network which predict the file that have high possibility to be accessed. Experiments show that compared with the traditional LRU and the plain grouping methods, the proposed model notably increase the cache hit rate and effectively reduces the I/O wait time.