Справочник Пользователя для National Instruments PCI-1428

Скачать
Страница из 51
Glossary
© National Instruments Corporation
G-3
D
DAQ
Data acquisition. (1) Collecting and measuring electrical signals from 
sensors, transducers, and test probes or fixtures and inputting them to a 
computer for processing. (2) Collecting and measuring the same kinds of 
electrical signals with A/D or DIO boards plugged into a computer, and 
possibly generating control signals with D/A and/or DIO boards in the 
same computer.
DC
Direct current.
default setting
A default parameter value recorded in the driver; in many cases, the default 
input of a control is a certain value (often 0) that means use the current 
default setting.
DMA
Direct memory access. A method by which data can be transferred to and 
from computer memory from and 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.
DRAM
Dynamic RAM.
drivers
Software that controls a specific hardware device, such as an image 
acquisition board.
dynamic range
The ratio of the largest signal level a circuit can handle to the smallest 
signal level it can handle (usually taken to be the noise level), normally 
expressed in decibels.
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.