Digital, Drift error, Gain error – Measurement Computing DataShuttle User Manual
Page 124: Ground loop, Hardware, Linearity error, Noise, Normal mode, Normal mode rejection, Offset error
Glossary - 2
11-12-01
DataShuttle and DynaRes
Digital
A quantity that has discrete levels. The number of people in a room is a digital quantity. See “Analog.”
Drift Error
The error that develops over time as physical properties of electronic circuits change.
Gain Error
The error in data which is the result of measurements being taken from different areas of the voltage range.
Ground Loop
A connection of ground wires such that current flows in them creating voltage drops that may interfere with
the signal. This is usually avoided by connecting all ground wires to the same ground.
Hardware
The physical part of a computer. The case, integrated circuits, disk drives, monitor, etc. See “Software.”
Linearity Error
The resulting error when a transducer provides a signal that varies in a non-linear way with the measured
phenomenon.
Noise
An external influence on electrical circuits. Noise can be random and unpredictable (such as that caused by
electromagnetic interference), or systematic and predictable (such as that caused by the 110V power lines in
a building).
Normal Mode
A voltage applied between the wires of a two wire (differential) input. The normal mode signal is the signal
measured at the input.
Normal Mode Rejection
A measure of the rejection of unwanted normal mode signal, usually AC. The ratio of the normal mode
input to the measured input due to the normal mode signal is the normal mode rejection ratio or NMRR. It
is usually specified at 60Hz in a circuit that measures DC inputs.
Offset Error
The error observed when the measured quantity is higher or lower than zero, while the actual quantity
equals zero.
Open Collector
A type of digital output in which the “off” state is nonconducting. In the “on” state, current can only flow
into the output toward ground (conventional current flow, the opposite of electron flow). The load for this
type of output is connected to a positive voltage. When the output is on, it goes low and current flows in the
load.
Peripheral Slot
A connector inside a computer that accepts additional circuit boards to perform new functions.
Pull-Up Resistor
This is a resistor that is often connected from an open collector output to a positive voltage. It pulls the
output high when it is off or nonconducting.