HP 54520 Series - Page 276

Glossary
Acquisition The process of sam-
pling and digitizing instantaneous
values of a continuous analog wave-
form and storing the values in
memory.
Acquisition system A combina-
tion of hardware and firraware that
performs the acquisition process and
assembles individual waveform sam-
ples into coherent waveform records.
Averaging Before updating the
display or measurements, the oscillo-
scope averages newly acquired data
with existing data. The higher the
number of averages, the less impact
each new waveform has on the com-
posite averaged waveform.
Averaging is typically used to elimi-
nate random noise from a repetitive
waveform.
Bit map A two-dimensional array
in which each element stores the
state of a corresponding pixel (dot)
ona video display. Typically, there
is one bit in the array for each pixel
on the display. The bit indicates
whether the pixel is illuminated (1)
or off (0).
Connect dots A straight line is
drawn between two-adjacent data
points on the display. Connect dots
is a display feature; it has no affect
on the waveform record stored in
memory or on measurements.
Delay Delay moves the waveform
horizontally on the display. Digitiz-
ing oscilloscopes allow you to view
events that happened before the trig-
ger event. A negative delay value is
time before the trigger event, and a
delay position value is time after the
trigger event. Some oscilloscopes re-
fer to delay as position.
Delay-by-events triggering The
trigger circuitry arms on an edge
from one of the channel or trigger in-
puts, waits for a number of events,
then triggers on an edge from any of
the channel or trigger inputs. Basi-
cally, it is two edge triggers
separated by a selectable number of
events.
Delay-by-time triggering The
trigger circuitry arms on an edge
from one of the channel or trigger in-
puts, waits for a time period, then
triggers on an edge from any of the
channel or trigger inputs. Basically,
it is two edge triggers separated by a
selectable time period.
Edge triggering The traditional
triggering mode. A trigger event is
defined as a transitioning edge of a
specified polarity crossing a speci-
fied voltage threshold.
Equivalent-time sampling
A term that is used on other oscillo-
scopes to refer to repetitive
Glossary -1