HP 54710A User's Reference Manual page 395

Glossary
Plug-in calibration The plug-in
calibration allows the oscilloscope to
establish the calibration factors for a
particular plug-in independent of the
mainframe in which it is calibrated.
These calibration factors are stored
in the plug-in's internal memory.
You can calibrate a plug-in to either
normal accuracy or calibrate it, in
conjunction with a specific
mainframe slot, to best accuracy.
Position Position moves the
waveform horizontally on the
display. Digitizing oscilloscopes
allow you to view events that
happened before the trigger event.
A negative position value is time
before the trigger event, and a
positive position value is time after
the trigger event. Some
oscilloscopes refer to position as
delay.
Real-time sampling All the data
points that make up a waveform
come from a single trigger event.
The real-time sampling mode is
typically used on events that occur
either once or infrequently.
Reconstruction Also known as
interpolation. Sampling theory
indicates that if a signal is
bandwidth-limited to less than half
of the sampling frequency (the
Nyquist frequency), the continuous
Glossary-4
signal can be determined exactly
from the sequence of samples. Two
problems exist in the real world to
prevent exact determination of the
continuous input. First, many
signals are not bandwidth-limited,
and second, the ideal determination
requires an infinite number of
samples. Reconstruction uses the
assumption that the signal has
minimal frequency components
above the Nyquist frequency in
order to accurately (but not exactly)
rebuild the continuous signal from
the finite set of discrete samples.
Record length The number of
waveform samples stored in the
waveform record. The greater the
memory depth, the greater the
amount of sampled data that is
available for analysis or
measurements.
Repetitive sampling A term that
is used on other oscilloscopes to
refer to equivalent time sampling.
The terms are interchangeable. See
"Equivalent time sampling" in this
glossary.