Tektronix TEKFAX ADA400A, Instruction Manual

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ADA400A Differential Preamplifier
65
Glossary
Alternating Current (AC)
An electric current whose instantaneous value and direction change
periodically.
Amplitude
The difference between a high and a low point on a waveform. Signal
amplitude can be measured in terms of “peak-to-peak” or “peak” for
example.
Attenuation
The degree the amplitude of a signal is reduced when it passes through an
attenuating device such as a probe or attenuator. That is, the ratio of the input
measure to the output measure. For example, a 10X attenuator will attenuate,
or reduce, the input voltage of a signal by a factor of 10.
Bandwidth
Bandwidth is the specified frequency range of the vertical system wherein
the vertical response is greater than or equal to 0.707 (--3dB) of the specified
frequency down to DC or 0 Hz.
Common mode
Signals on both preamplifier inputs that are identical in voltage and phase.
Common-Mode Rejection Ratio (CMRR)
The extent to which a differential amplifier rejects a common-mode voltage
presented on the inputs. CMRR is the ratio of the differential gain to the
common-mode gain and is usually expressed in decibels (dB).
Coupling
The method of connecting the input circuit to the signal source. A coupling
circuit, for example, may pass only AC signals above a certain frequency.
Differential
Signals that are not identical in amplitude or phase and thereby present a
difference on the inputs of the preamplifier.
Direct Current
An electric current that flows in only one direction with essentially constant
value.
Frequency
A timing measurement that is the reciprocal of the period. Frequency is
measured in Hertz (Hz) where 1 Hz = 1 cycle per second.
Floating
A signal or voltage that does not have a reference to ground.