Glossary
G-4
ni.com
DAQ-STC
data acquisition system timing controller—an application-specific
integrated circuit (ASIC) for the system timing requirements of a general
A/D and D/A system, such as a system containing the National
Instruments E Series devices
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—an analog input mode consisting of two terminals,
both of which are isolated from computer ground, whose difference is
measured
DIO
digital input/output
DIP
dual inline package
dithering
the addition of Gaussian noise to an analog input signal for the purpose
of increasing the resolution of a measurement when using averaging
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; 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
ENOB
effective number of bits
