LeCroy LSA1000, Operator'S Manual

Page: 95 / 115

C – 11
Parameter Measurement
Parameter — Description Definition Notes
rms Root Mean Square of data between the
cursors
— about same as
sdev for a
zero-mean waveform.
1
2
1
N
v
i
i
N
( )
=

(See Fig. C
–2)
Gives similar result when applied to
time domain waveform or histogram
of data of same waveform. But with
histograms, result may include
contributions from more than one
acquisition.
Where: v
i
denotes measured sample
values, and
N =
number of data
points within the periods found up to
maximum of 100 periods.
sdev Standard deviation of the data between
the cursors
— about the same as
rms for
a zero-mean waveform.

=
−
N
i
i
) mean v (
N
1
2
1
(See Fig. C
–2)
Gives similar result when applied to
time domain waveform or histogram
of data of same waveform. But with
histograms, result may include
contributions from more than one
acquisition.
Where: v
i
denotes measured
sample values, and
N =
number of
data points within the periods found
up to maximum of 100 periods.
t@level Time at level: Time from trigger (t=0) to
crossing at a specified level. Time from trigger
to crossing level
top Higher of two most probable states, the lower
being
base . This is characteristic of rectangular
waveforms and represents the higher most
probable state determined from the statistical
distribution of
data point values in the waveform.
Value of most
probable higher
state
(See Fig. C
–1)
Gives similar result when
applied
to time domain
waveform or histogram of data
of same waveform. But with
histograms, result may include
contributions from more than
one acquisition.
width Width of cyclic signal determined by examining
50 % crossings in data input. If first transmission
after left cursor is a rising edge, waveform is
considered to consist of positive pulses and
width the time between adjacent rising and
falling edges. Conversely, if falling edge, pulses
are considered negative and
width the time
between adjacent falling and rising edges. For
both cases, widths of all waveform pulses
averaged for final result.
Width of first
positive or
negative pulse
averaged for all
similar pulses
(See Figs. 1, 2)
Similar to fwhm , which,
however, applies only to
histograms.