National Instruments Data Acquisition Device NI USB-621x User Manual
Page 161
Glossary
© National Instruments Corporation
G-3
arm
The process of getting an instrument ready to perform a function. For
example, the trigger circuitry of a digitizer is armed, meaning that it is
ready to start acquiring data when an appropriate trigger condition is met.
ASIC
Application-specific integrated circuit—A proprietary semiconductor
component designed and manufactured to perform a set of specific
functions for a specific customer.
asynchronous
1. Hardware—A property of an event that occurs at an arbitrary time,
without synchronization to a reference clock.
2. Software—A property of a function that begins an operation and
returns prior to the completion or termination of the operation.
B
b
Bit—One binary digit, either 0 or 1.
B
Byte—Eight related bits of data, an eight-bit binary number. Also used to
denote the amount of memory required to store one byte of data.
block diagram
A pictorial description or representation of a program or algorithm.
buffer
1. Temporary storage for acquired or generated data.
2. A memory device that stores intermediate data between two devices.
bus, buses
The group of electrical 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 PCI, AT (ISA), and
EISA bus.
C
C
Celsius.
calibration
The process of determining the accuracy of an instrument. In a formal
sense, calibration establishes the relationship of an instrument’s
measurement to the value provided by a standard. When that relationship is
known, the instrument may then be adjusted (calibrated) for best accuracy.
cascading
Process of extending the counting range of a counter chip by connecting to
the next higher counter.