Glossary
G-6
©
National Instruments Corporation
I
IC
integrated circuit
ICP
Integrated Circuit Piezoelectric—identifies products that operate using a
constant current source and returns the output signal in the form of voltage
modulation on the same line as the constant current source.
IMD
intermodulation distortion—the ratio, in dB, of the total rms signal level of
harmonic sum and difference distortion products, to the overall rms signal
level. The test signal is two sine waves added together according to the
following standards:
SMPTE—A 60 Hz sine wave and a 7 kHz sine wave added in a
4:1 amplitude ratio.
DIN—A 250 Hz sine wave and an 8 kHz sine wave added in a
4:1 amplitude ratio.
CCIF—A 14 kHz sine wave and a 15 kHz sine wave added in a
1:1 amplitude ratio.
in.
inches
INL
integral nonlinearity—a measure in LSB of the worst-case deviation from
the ideal A/D or D/A transfer characteristic of the analog I/O circuitry
input bias current
the current that flows into the inputs of a circuit
input impedance
the measured resistance and capacitance between the input terminals of a
circuit
input offset current
the difference in the input bias currents of the two inputs of an
instrumentation amplifier
instrumentation
amplifier
a circuit whose output voltage with respect to ground is proportional to the
difference between the voltages at its two inputs
I/O
input/output—the transfer of data to/from a computer system involving
communications channels, operator interface devices, and/or data
acquisition and control interfaces
I
OH
current, output high
I
OL
current, output low
UM.book Page 6 Tuesday, July 14, 1998 10:37 AM
