National Instruments NI 4050 用户手册
Glossary
© National Instruments Corporation
G-3
CompactPCI
refers to the core specification defined by the PCI Industrial Computer
Manufacturer’s Group (PICMG)
Manufacturer’s Group (PICMG)
conversion device
device that transforms a signal from one form to another. For example,
analog-to-digital converters (ADCs) for analog input, digital-to-analog
converters (DACs) for analog output, digital input or output ports, and
counter/timers are conversion devices.
analog-to-digital converters (ADCs) for analog input, digital-to-analog
converters (DACs) for analog output, digital input or output ports, and
counter/timers are conversion devices.
conversion time
the time required, in an analog input or output system, from the moment a
channel is interrogated (such as with a read instruction) to the moment that
accurate data is available
channel is interrogated (such as with a read instruction) to the moment that
accurate data is available
coupling
the manner in which a signal is connected from one location to another
CPU
central processing unit
crest factor
the ratio of the peak value of the signal to the RMS value of the signal
CSM
current shunt module
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 and/or DIO boards plugged into a computer, and
possibly generating control signals with D/A and/or DIO boards in the
same computer
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 and/or DIO boards plugged into a computer, and
possibly generating control signals with D/A and/or DIO boards in the
same computer
dB
decibel—the unit for expressing a logarithmic measure of the ratio of two
signal levels: dB=20log10 V1/V2, for signals in volts
signal levels: dB=20log10 V1/V2, for signals in volts
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.
input of a control is a certain value (often 0) that means use the current
default setting.
device
a plug-in data acquisition board, card, or pad that can contain multiple
channels and conversion devices. Plug-in boards, PCMCIA cards,
devices such as the DAQPad-1200, which connects to your computer
parallel port, are all examples of DAQ devices.
channels and conversion devices. Plug-in boards, PCMCIA cards,
devices such as the DAQPad-1200, which connects to your computer
parallel port, are all examples of DAQ devices.