Data acquisition and conversion systems are used to acquire analog signals from one or more sources and convert these signals into digital form for analysis or transmission by end devices such as digital computers, recorders, or communications networks. The analog signal inputs to data acquisition systems are most often generated from sensors and transducers which convert real-world parameters such as pressure, temperature, stress or strain, flow, etc, into equivalent electrical signals. The electrically equivalent signals are then converted by the data acquisition system and are then utilized by the end devices in digital form. The ability of the electronic system to preserve signal accuracy and integrity is the main measure of the quality of the system.
The basic components required for the acquisition and conversion of analog signals into equivalent digital form are the following:
Typically, today’s data acquisition systems contain all the elements needed for data acquisition and conversion, except perhaps, for input filtering and signal conditioning prior to analog multiplexing. The analog signals are time multiplexed by the analog multiplier; the multiplexer output signal is then usually applied to a very-linear fast-settling differential amplifier and/or to a fast-settling low aperture sample/hold. The sample/hold is programmed to acquire and hold each multiplexed data sample which is converted into digital form by an A/D converter. The converted sample is then presented at the output of the A/D converter in parallel and serial digital form for further processing by the end devices.