HP 54520 Series - Page 279

Glossary
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 avail-
able for analysis or measurements.
Repetitive sampling A waveform
is reconstructed from data points
that are acquired from several trig-
ger events. The repetitive sampling
mode is typically used on repetitive
signals.
Sample rate The rate at which
the acquisition system samples a
waveform. In the real-time mode, all
samples in a given waveform record
are taken from one trigger event and
are evenly spaced in time at a dis-
tance of 1/sample rate. In the
repetitive mode and when less than
500 points are captured on each ac-
quisition, a waveform record is built
up by interleaving samples taken
from multiple trigger events. This
process allows samples in the wave-
form record to be spaced more
closely together for repetitive wave-
forms. As a result, the waveforms
appear to have been sampled at a
much higher rate, sometimes re-
ferred to as an effective sample
rate. The effective sample rate is re-
cord length/time length of the
record. This is the same as 1/(time
between the sample points) or
1/{time base resolution).
Scale (channel) Channe! scale
controls the vertical scaling of dis-
played waveforms.
Scale (time base) Time base
scale controls the horizontal scaling
of displayed waveforms. Time base
scale is often referred to as sweep
speed in other oscilloscopes.
Skew Skew changes the horizontal
position of a waveform on the dis-
play independent of any other
waveforms on the display. The time
base position control moves all of the
waveforms on the display at the
same time, whereas skew moves indi-
vidual waveforms. Skew is typically
used for overlaying waveforms, or
eliminating timing difference caused
by diverse cable and probe lengths.
State triggering State triggering
is an edge qualified, pattern trigger.
A trigger event occurs if a 3-bit pat-
tern is present when an edge occurs
on the designated clock waveform.
Glossary—4