LeCroy LSA1000, Руководство оператора

Страница: 89 / 115

C – 5
Parameter Measurement
Parameter — Description Definition Notes
a m p l Amplitude: Measures difference between
upper and lower levels in two-level
signals. Differs from
pkpk in that noise,
overshoot, undershoot, and ringing do
NOT
affect measurement.
top - base
(See Fig. C
–1)
On signals
NOT
having two
major levels (such as triangle
or saw-tooth waves), returns
same value as
pkpk .
a r e a Integral of data: Computes area of
waveform between cursors relative to
zero level. Values greater than zero
contribute positively to the area; values
less than zero negatively. Sum from first to
last of data
multiplied by
horizontal time
between points
(See Fig. C
–2)
b a s e Lower of two most probable states (higher
is
top ). Measures lower level in two-level
signals. Differs from min in that noise,
overshoot, undershoot, and ringing do
NOT
affect measurement.
Value of most
probable lower
state
(See Fig. C
–1)
On signals
NOT
having two
major levels (triangle or saw-
tooth waves, for example),
returns same value as
min .
c y c l e s
Determines number of cycles of a periodic
waveform lying between cursors. First
cycle begins at first transition after the left
cursor. Transition may be positive- or
negative-going. Number of
cycles of periodic
waveform
(See Fig. C
–2)
c m e a n Cyclic mean: Computes the average of
waveform data. Contrary to mean ,
computes average over an integral
number of cycles, eliminating bias caused
by fractional intervals.
Average of data
values of an
integral number
of periods
cmedian Cyclic median: Computes average of
base and top values over an integral
number of cycles, contrary to
median ,
eliminating bias caused by fractional
intervals.
Data value for
which 50 % of
values are above
and 50 % below
c r m s Cyclic root mean square: Computes
square root of sum of squares of data
values divided by number of points.
Contrary to
rms , calculation performed
over integral number of cycles, eliminating
bias caused by fractional intervals.
1
2
1
N
v
i
i
N
( )
=

Where: v
i
denotes measured
sample values, and
N =
number
of data points within the periods
found up to maximum of 100
periods.