National Instruments 5411 - Manual (Page 71)

Glossary
© National Instruments Corporation G-5 DAQArb 5411 User Manual
E
EEPROM electrically erasable programmable read-only memory—ROM that can
be erased with an electrical signal and reprogrammed
external trigger a voltage pulse from an external source that triggers an event such as
A/D conversion
EXT_TRIG external trigger input signal
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.
filters digital or analog circuits that change the frequency characteristics of a
waveform
frequency resolution the smallest frequency change that can be generated by a DAQArb 5411
ft feet
G
gain the factor by which a signal is amplified, sometimes expressed in
decibels