Teledyne LeCroy WaveRunner XI SERIES Operator’s Manual - Manual (Page 110)

W
AVE
R
UNNER
X
I
S
ERIES
110
WRXi-OM-E Rev C
IMES
f the rise and fall times is easily done (see Figure 1). The 90% and
the amplitude (ampl) parameter.
f
ative settings are chosen, the vertical interval spanned between the
base and top lines is subdivided into a percentile scale (base = 0 %, top = 100 %) to determine the vertical
position of the crossing points.
The time interval separating the points on the rising or falling edges is then estimated to yield the rise or fall time.
These result
d over the number of transition edges that occur within the observation window.
D ETERMINING R ISE AND F ALL T
Once top and base are estimated, calculation o
10% threshold levels are automatically determined by the DDA-5005, using
Threshold levels for rise or fall time can also be selected using absolute or relative settings (r@level, f@level). I
absolute settings are chosen, the rise or fall time is measured as the time interval separating the two crossing
points on a rising or falling edge. But when rel
s are average
Rising Edge Duration:
Falling Edge Duration:
Where Mr is the number of leading edges found, Mf the number of trailing edges found, the time when
rising edge i crosses the x% level, and the time when falling edge i crosses the x% level.
Determining Time Parameters
Time parameter mea urements such as width, period and delay are carried out with respect to the mesial
integer, parameter measurements such as rms or mean will be biased. However, only
, the mean being available when statistics are enabled. To avoid these bias
clic parameters, including crms and cmean, that restrict the calculation to an
s
reference level (see Figure 2), located halfway (50%) between the top and base reference lines.
Time-parameter estimation depends on the number of cycles included within the observation window. If the
number of cycles is not an
the last value is actually displayed
effects, the instrument uses cy
integer number of cycles.
Figure 2