Data Acquisition Toolbox

The Analog Input Subsystem

Many data acquisition hardware devices contain one or more subsystems that convert (digitize) real-world sensor signals into numbers your computer can read. Such devices are called analog input subsystems (AI subsystems, A/D converters, or ADCs). After the real-world signal is digitized, you can analyze it, store it in system memory, or store it to a disk file.

The function of the analog input subsystem is to sample and quantize the analog signal using one or more channels. You can think of a channel as a path through which the sensor signal travels. Typical analog input subsystems have eight or 16 input channels available to you. After data is sampled and quantized, it must be transferred to system memory.

Analog signals are continuous in time and in amplitude (within predefined limits). Sampling takes a "snapshot" of the signal at discrete times, while quantization divides the voltage (or current) value into discrete amplitudes. Sampling, quantization, channel configuration, and transferring data from hardware to system memory are discussed below.

Software

Sampling