Editing Data acquisition (section)

===Sources and systems===

Data acquisition begins with the [[physical phenomenon]] or [[physical property]] to be measured. Examples of this include temperature, vibration, light intensity, gas pressure, fluid flow, and force. Regardless of the type of physical property to be measured, the physical state that is to be measured must first be transformed into a unified form that can be sampled by a data acquisition system. The task of performing such transformations falls on devices called ''sensors''. A data acquisition system is a collection of software and hardware that allows one to measure or control the physical characteristics of something in the real world. A complete data acquisition system consists of DAQ hardware, sensors and actuators, signal conditioning hardware, and a computer running DAQ software. If timing is necessary (such as for event mode DAQ systems), a separate compensated distributed timing system is required.

A [[sensor]], which is a type of ''[[transducer]]'', is a device that converts a physical property into a corresponding electrical signal (e.g., [[strain gauge]], thermistor). An acquisition system to measure different properties depends on the sensors that are suited to detect those properties. Signal conditioning may be necessary if the signal from the transducer is not suitable for the DAQ hardware being used. The signal may need to be filtered, shaped, or amplified in most cases. Various other examples of signal conditioning might be bridge completion, providing current or voltage excitation to the sensor, isolation, and linearization.  For transmission purposes, [[Single-ended signalling|single ended]] [[analog signals]], which are more susceptible to noise can be converted to [[Differential signaling|differential signals]]. Once digitized, the signal can be encoded to reduce and correct transmission errors.