Glossary
NI5911 User Manual G-6 ni.com
N
noise an undesirable electrical signal—Noise comes from external sources such
asthe AC power line, motors, generators, transformers, fluorescent lights,
solderingirons, CRT displays, computers, electrical storms, welders, radio
transmitters, and internal sources such as semiconductors, resistors, and
capacitors.N oise corrupts signals you are trying to send or receive.
Nyquist frequency afreq uencythat is one-halft he sampling rate. See Nyquist Sampling
Theorem
Nyquist Sampling
Theorem
the theorem states that if a continuous bandwidth-limited analog signal
containsno frequency components higher than half the frequency at which
it is sampled, then the original signal can be recovered without distortion.
O
Ohm’sLaw (R=V/I)—therelationship of voltage to current in a resistance
overrange asegment of the input range of an instrument outside of the normal
measuring range. Measurements can still be made, usually with a
degradationin specifications.
oversampling sampling at a rate greater than the Nyquist frequency
P
passband the frequencyrange that a filter passes without attenuation
PCI Peripheral Component Interconnect—a high-performance expansion bus
architecture originally developedby Intel to replace ISA and EISA; it is
achievingwidespread acceptance as a standard for PCs and workstations
and offersa theoretical maximum transfer rate of 132 Mbytes/s
peakvalue theabsolute maximum or minimum amplitude of a signal (AC + DC)
posttriggering the technique to acquire a programmed number of samples after trigger
conditions are met