Data Acquisition

Data acquisition is a general term that encompasses the process of turning real world phenomenon such as sound or temperature into a sequence of digital data. The process can be broken down into several steps and analyzed individually.
First, the physical phenomenon must be converted into some type of electrical signal. Usually, the resulting signal is proportional to the magnitude of the physical phenomenon being sensed. The device dedicated to detecting a specific type of physical phenomenon is known as a sensor.
Second, the output of the sensor is fed into the input of an analog-to-digital converter (ADC). The ADC conversion is perhaps the most complex part of the overall data acquisition process. In order to select the appropriate ADC hardware, the physical phenomenon in question must be well understood. Acquiring sound data such as music or speech will require a fast sample rate to avoid aliasing. The sensor should have a large enough output swing to satisfy the dynamic range of the ADC to meet the full-scale capabilities of the ADC. For battery powered data acquisition systems, the ADC should be as low power as possible.
Some manipulation of the digital data after conversion can still be considered as part of the acquisition process. The data may be corrected to compensate for known biases in the sensor. Also, the data may be converted into a format more appropriate for analysis via software.