数据采集
    数据采集是对现实世界抽样产生出可以由计算机操纵的数据，有时也把它缩写为DAS或者DAQ，数据采集和信号通常涉及到的信号波形采集和处理，以获得所需的信息。数据采集系统的组成部分包括的任何测量参数转换为电信号，然后调节电信号，然后再通过数据采集硬件获取相应数据的传感器。

    使用厂商提供的软件，或自定义显示和控制，开发利用如BASIC，C，Fortran，Java，Lisp，Pascal各种通用编程语言把获得的数据显示，分析和存储在计算机中。为了构建大规模数据采集系统，使用了包括EPICS等专业的编程语言进行的数据采集。LabVIEW，内置了图形化工具和数据的采集和分析，它提供了图形化编程环境数据采集优化，并使用MATLAB作为其编程语言。

数据是如何取得
(1)accessible是什么意思中文来源
    根据调查，数据采集是和物理现象或物体的物理性质一起开始的。这物理性质或现象，可能是根据温度或房间温度，强度或光源的强度变化而变化，内部的压力，迫使应用到一个对象，或许多其他事情。一个有效的数据采集系统可以测量这些不同性质或现象。

    换能器是一种可以将电压，电流，电阻或电容值的变化等转换成相应的可测量的电信号的装置，数据采集系统衡量不同的物理现象的能力，取决于换能器把数据采集硬件采集到的可测量的物理现象转换成可测量信号。在DAQ系统中，传感器是感应器的代名词。不同的传感器有许多不同的应用，如测量温度，压力，或液体流动。数据采集还进行各种信号调理技术，将充分修改各种不同的电压，使之变为可以使用ADC测量的数字化电信号。

(2)信号
    信号可能是数字信号（有时也称为逻辑信号）或使用不同的传感器进行模拟分析的结果。
    如果从传感器得到的信号与数据采集硬件不兼容，信号调理就是非常必要的了。该信号可以被放大，或者可能需要过滤，或锁定放大器解调列入执行。
模拟信号容忍几乎没有串音等转换为数字数据，然后才接近一台PC或之前沿长电缆。对于模
拟数据，具有很高的信噪比，信号需要非常高，同时派遣一个50欧姆的终端快速信号路径+ -10伏特，需要强大的驱动程序。

(3)数据采集硬件
    数据采集硬件通常是与信号和PC接口。它可以从母板连接到计算机的端口（并行，串行，USB等..）或连接到插槽卡（PCI，ISA和PCI - E等..）。通常在一个PCI卡背面的空间太小，不能满足所有需要的连接的血药，所以外部的盒式是必需的。这之间的电缆盒和PC是昂贵的原因是许多的电线需屏蔽。
数据采集卡通常包含复用器，模数转换，数模转换，与TTL印务局，高速定时器，RAM等多个组件。这些都可以通过由一个可以运行小程序的总线的微控制器进行控制。该控制器比硬布线逻辑灵活，但比CPU便宜，所以用它阻止它用简单的投票循环是没有问题。例如：等待一个触发，启动ADC时，查的时间，等待完成的ADC，移动值到RAM，切换多路，得到TTL输入，让数模转换器进行电压斜坡。由于16位模数转换器，数模转换器，运算放大器和样品，并作为2007年只有1兆赫运行等精度认为，即使像成本低为AVR32数字控制器有簿记之间约100个时钟周期。
    可重构计算可提供高速数字信号。数字信号处理器算法花费大量的硅，并允许严格控制回路或过滤器。与个人电脑连接允许舒适固定编制和调试。使用外部住房在1总线插槽模块化设计，可以增加与用户的需求。高速二进制数据需要特殊用途的硬件要求时向数字转换器和高速8位ADC称为数字存储示波器示波器＃，这是典型的未连接到DAQ硬件，而是直接到PC。
另外值得注意的是，并非所有的数据采集硬件的运行永久连接到电脑上，例如智能独立伐木者和控制器，可以从电脑操作，但他们可以经营完全独立的个人电脑。

(4)数据采集软件
    数据采集软件，是为了对数据采集硬件与PC的工作。这样可能会至少在三个方面：应用程序直接从硬件寄存器，低层次的软件驱动程序（通常包装与数据采集硬件），让开发更高级别的应用程序注册资料从硬件和越野的现成应用程序来
驱动软件，通常与数据采集硬件或其他厂商来了，让操作系统识别的数据采集硬件和程序访问的信号正由数据采集硬件阅读。一个优秀的车手提供了高，低级别的访问。所以，一开始时会与高级别提供的解决办法，提高到组装说明在时间关键的或外来的申请。
场外的现成应用程序编程接口的手段包括记录，分析和显示所获得的数据。这种软件的例子是MATLAB和LabVIEW中，既提供一个高层次的图形化编程语言。
Data acquisition
    Data acquisition is the sampling of the real world to generate data that can be manipulated by a computer. Sometimes abbreviated DAQ or DAS, data acquisition typically involves acquisition of signals and waveforms and processing the signals to obtain desired information. The components of data acquisition systems include appropriate sensors that convert any measurement parameter to an electrical signal, then conditioning the electrical signal which can then be acquired by data acquisition hardware.
    Acquired data are displayed, analyzed, and stored on a computer, either using vendor supplied software, or custom displays and control can be developed using various general purpose programming languages such as BASIC, C, Fortran, Java, Lisp, Pascal. Specialized programming languages used for data acquisition include EPICS, used to build large scale data acquisition systems, LabVIEW, which offers a graphical programming envir
onment optimized for data acquisition, and MATLAB which provides a programming language, and also built-in graphical tools and libraries for data acquisition and analysis.
How data is acquired
Source
    Data acquisition begins with the physical phenomenon or physical property of an object (under investigation) to be measured. This physical property or phenomenon could be the temperature or temperature change of a room, the intensity or intensity change of a light source, the pressure inside a chamber, the force applied to an object, or many other things. An effective data acquisition system can measure all of these different properties or phenomena.
    A transducer is a device that converts a physical property or phenomenon into a corresponding measurable electrical signal, such as voltage, current, change in resistance or capacitor values, etc. The ability of a data acquisition system to measure different pheno
mena depends on the transducers to convert the physical phenomena into signals measurable by the data acquisition hardware. Transducers are synonymous with sensors in DAQ systems. There are specific transducers for many different applications, such as measuring temperature, pressure, or fluid flow. DAQ also deploy various signal conditioning techniques to adequately modify various different electrical signals into voltage that can then be digitized using ADCs.
Signals
    Signals may be digital (also called logic signals sometimes) or analog depending on the transducer used.
    Signal conditioning may be necessary if the signal from the transducer is not suitable for the DAQ hardware to be used. The signal may be amplified, or may require filtering, or a lock-in amplifier is included to perform demodulation.
Analog signals tolerate almost no cross talk and so are converted to digital data, before co
ming close to a PC or before traveling along long cables. For analog data to have a high signal to noise ratio, the signal needs to be very high, and sending +-10 Volts along a fast signal path with a 50 Ohm termination requires powerful drivers.
DAQ hardware
    DAQ hardware is what usually interfaces between the signal and a PC. It could be in the form of modules that can be connected to the computer's ports (parallel, serial, USB, ) or cards connected to slots (PCI, ISA, PCI-E, ) in the mother board. Usually the space on the back of a PCI card is too small for all the connections needed, so an external breakout box is required. The cable between this Box and the PC is expensive due to the many wires and the required shielding and because it is exotic.
    DAQ-cards often contain multiple components (multiplexer, ADC, DAC, TTL-IO, high speed timers, RAM). These are accessible via a bus by a micro controller, which can run small programs. The controller is more flexible than a hard wired logic, yet cheaper than a CPU so that it is alright to block it with simple polling loops. For example: Waiting for a trigg
er, starting the ADC, looking up the time, waiting for the ADC to finish, move value to RAM, switch multiplexer, get TTL input, let DAC proceed with voltage ramp. As 16 bit ADCs, DACs, OpAmps and sample and holds with equal precision as of 2007 only run at 1 MHz, even low cost digital controllers like the AVR32 have about 100 clock cycles for bookkeeping in between.
    Reconfigurable computing may deliver high speed for digital signals. Digital signal processors spend a lot of silicon on arithmetic and allow tight control loops or filters. The fixed connection with the PC allows for comfortable compilation and debugging. Using an external housing a modular design with slots in a bus can grow with the needs of the user. High speed binary data needs special purpose hardware called Time to digital converter and high speed 8 bit ADCs are called oscilloscope#Digital storage oscilloscope, which are typically not connected to DAQ hardware, but directly to the PC.

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