Glossary
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National Instruments Corporation
G-3
PCI-6023E/6024E/6025E User Manual
base address
a memory address that serves as the starting address for programmable
registers. All other addresses are located by adding to the base address.
BIOS
basic input/output system—BIOS functions are the fundamental level of
any PC or compatible computer. BIOS functions embody the basic
operations needed for successful use of the computer’s hardware resources.
bipolar
a signal range that includes both positive and negative values (for example,
–5 V to +5 V)
breakdown voltage
the voltage high enough to cause breakdown of optical isolation,
semiconductors, or dielectric materials. See also working voltage.
burst-mode
a high-speed data transfer in which the address of the data is sent followed
by back-to-back data words while a physical signal is asserted
bus
the group of conductors that interconnect individual circuitry in a computer.
Typically, a bus is the expansion vehicle to which I/O or other devices are
connected. Examples of PC buses are the ISA and PCI bus.
bus master
a type of a plug-in board or controller with the ability to read and write
devices on the computer bus
C
C
Celsius
CalDAC
calibration DAC
CH
channel—pin or wire lead to which you apply or from which you read the
analog or digital signal. Analog signals can be single-ended or differential.
For digital signals, you group channels to form ports. Ports usually consist
of either four or eight digital channels.
channel clock
the clock controlling the time interval between individual channel sampling
within a scan. Boards with simultaneous sampling do not have this clock.
CMRR
common-mode rejection ratio—a measure of an instrument’s ability to
reject interference from a common-mode signal, usually expressed in
decibels (dB)
cold-junction
compensation
a method of compensating for inaccuracies in thermocouple circuits
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