Glossary
National Instruments Corporation
G-7
VXI-MIO Series User Manual
F
FIFO
first-in-first-out memory buffer—The first data stored is the first
data sent to the acceptor. FIFOs are often used on DAQ devices to
temporarily store incoming or outgoing data until that data can be
retrieved or output. For example, an analog input FIFO stores the
results of A/D conversions until the data can be retrieved into
system memory, a process that requires the servicing of interrupts
and often the programming of the DMA controller. This process
can take several milliseconds in some cases. During this time,
data accumulates in the FIFO for future retrieval. With a larger
FIFO, longer latencies can be tolerated. In the case of analog
output, a FIFO permits faster update rates, because the waveform
data can be stored on the FIFO ahead of time. This again reduces
the effect of latencies associated with getting the data from system
memory to the DAQ device.
floating signal sources
Signal sources with voltage signals that are not connected to an
absolute reference or system ground. Also called nonreferenced
signal sources. Some common example of floating signal sources
are batteries, transformers, or thermocouples.
FREQ_OUT
frequency output signal
ft
feet
function
A set of software instructions executed by a single line of code
that may have input and/or output parameters and returns a value
when executed.
G
gain
The factor by which a signal is amplified, sometimes expressed in
decibels.
gain accuracy
A measure of deviation of the gain of an amplifier from the ideal
gain.
GND
ground signal or bit
GPCTR0_GATE
general purpose counter 0 gate signal
GPCTR1_GATE
general purpose counter 1 gate signal
GPCTR0_OUT
general purpose counter 0 output signal
GPCTR1_OUT
general purpose counter 1 output signal
GPCTR0_SOURCE
general purpose counter 0 clock source signal
