Glossary
G-4
©
National Instruments Corporation
general A/D and D/A system, such as a system containing the
National Instruments E Series boards.
dB
decibel—the unit for expressing a logarithmic measure of the ratio
of two signal levels: dB=20log10 V1/V2, for signals in volts
DC
direct current
DGND
digital ground signal
DI
digital input
DIFF
differential mode
DIO
digital input/output
DIP
dual inline package
dithering
the addition of Gaussian noise to an analog input signal
DMA
direct memory access—a method by which data can be transferred
to/from computer memory from/to a device or memory on the bus
while the processor does something else. DMA is the fastest
method of transferring data to/from computer memory.
DNL
differential nonlinearity—a measure in least significant bit of the
worst-case deviation of code widths from their ideal value of 1 LSB
DO
digital output
E
EEPROM
electrically erasable programmable read-only memory—ROM that
can be erased with an electrical signal and reprogrammed
EXTSTROBE
external strobe signal
F
FIFO
first-in first-out memory buffer—FIFOs are often used on DAQ
devices to temporarily store incoming or outgoing data until that
data can be read or written. For example, an analog input FIFO
stores the results of A/D conversions until the data can be read into
PCI_E.book Page 4 Thursday, June 25, 1998 12:55 PM