The development of electronic computing technology, especially the rapid development of embedded systems and applications, is causing digital circuit technology to be the foundation of measurement systems. The traditional concept of instruments (transducer – signal conditioning – display – print functional expansion) has evolved to become (test – data acquisition – data processing – storage – transmission) in an integrated and complex system. Data Acquisition (DAQ) combines these two technologies: gathering raw data from sensors, and the subsequent data processing.  With sensors becoming more integrated and intelligent, the boundary between sensors and measurement systems has become increasingly blurred. Therefore, sometimes sensor technology is considered to be within the scope of data processing technology.

The technical field of data acquisition techniques covers a wide range.  Broadly speaking, any method of gathering information, (including electronic and non-electronic data) can be regarded as data acquisition. For example, obtaining needed data from a database on a computer network.

Usually, measured physical parameters such as temperature, humidity, pressure, distance, etc, are analog signals. And analog sensors convert these physical parameters to analog electronic output signals which are also analog, continuous functions in time.

The data acquisition task is to covert these continuous-time functions into digital signals that can be easily handled by digital signal processors. So, data acquisition connects the analog physical signal to a digital electronic circuit interface. So data capture techniques include both hardware and software technologies [1].

A data acquisition system design should typically consider requirements for the following technical capabilities:

（1）has a data acquisition rate that is fast enough to meet application requirements;

（2）provides anti-aliasing, and filtering for high frequency noise;

（3）can be adapted to measure the sensor output signal of the specific sensor types;

（4）provides electrical excitation signal source to the sensors if they need it;

（5）can measure the signal of interest throughout the entire operating range (for example:  maximum and minimum voltage);

（6）provides any required signal conditioning and signal isolation;

（7）provides any required mechanical interface;

（8）meets the performance requirements of resolution, accuracy, and low noise level;

（9）ideally, provides simultaneous multi-channel signal acquisition; this should be based on whether the signal is collected

simultaneously and on the required sensitivity of the acquisition;

（10）provides any required supporting software.

Citations

[1] Dong Yonggui. “Sensor technology and systems,” Tsinghua University Press.