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Oscilloscope Terms
6
Oscilloscope Terms
6.1
- A -
‘AUTO-SETUP’ MODE
The oscilloscope automatically selects a setting for volts/div and time/div in such a way that one or
more periods of signal are displayed correctly.
AC COUPLING
The oscilloscope only displays the AC component of a signal, any DC level is ignored.
ACCELERATING VOLTAGE
Tthe internal voltage that accelerates the electron beam and causes trace illumination on the
oscilloscope display. Usually measured in kilovolts (kV).
ALIASING
In signal processing, aliasing refers to an effect that causes different signals to become
indistinguishable when sampled. It also refers to the distortion or artifact that results when the signal
reconstructed from samples is different from the original continuous signal. Aliasing can occur in
signals sampled in time, for instance digital audio, and is referred to as temporal aliasing.
AMPLITUDE
How far does the signal ‘swing’ in a direction. Expressed in mV or V.
For repetitive signals: Vpeak (Vpp).
ANALOG
Analog scopes use the incoming signal to deflect an electron beam, which scans from left to right on
the screen. The electron beam leaves an image on the screen which represents the signal you’ve
applied. Analog signals are continuously variable.
ATTENUATION
A decrease in signal amplitude, measured in decibels (dB).
AVERAGING MODE
A processing technique used by digital oscilloscopes to eliminate noise in a displayed signal.
6.2
- B -
BANDWIDTH
Usually expressed in MHz. It is the frequency at which an applied sine wave will be displayed at an
amplitude of around 70% of its original amplitude. More expensive scopes feature a higher
bandwidth. Rule of thumb: the bandwidth of an oscilloscope needs to be at least 5 times higher than
the frequency of the signal applied to the input of the scope.
6.3
- C -
CHANNEL
This is the input circuit consisting a vertical attenuator, vertical amplifier and an input coupling
network.
CIRCUIT LOADING
The unintentional interaction of the probe and oscilloscope with the circuit being tested which
distorts a signal.
