National Instruments NI USB-621x 154

	Glossary
counter/timer	A circuit that counts external pulses or clock pulses (timing).
D
D GND	Digital ground signal.
D-SUB connector	A serial connector.
DAC	Digital-to-Analog Converter—An electronic device, often an integrated
	circuit, that converts a digital number into a corresponding analog voltage
	or current.
	In the instrumentation world, DACs can be used to generate arbitrary
	waveform shapes, defined by the software algorithm that computes the
	digital data pattern, which is fed to the DAC.
DAQ	1. Data acquisition—The process of collecting and measuring electrical
	signals from sensors, transducers, and test probes or fixtures and
	inputting them to a computer for processing.
	2. Data acquisition—The process of collecting and measuring the same
	kinds of electrical signals with A/D and/or DIO devices plugged into a
	computer, and possibly generating control signals with D/A and/or
	DIO devices in the same computer.
DAQ device	A device that acquires or generates data and can contain multiple channels
	and conversion devices. DAQ devices include plug-in devices, PCMCIA
	cards, and DAQPad devices, which connect to a computer USB or 1394
	(FireWire®) port. SCXI modules are considered DAQ devices.
DAQ-STC2	Data acquisition system timing controller chip.
data acquisition	The general concept of acquiring data, as in begin data acquisition or data
	acquisition and control. See also DAQ.

G-5