User manual

33
Measurements
σ-STD.DEVIATION: This mode measures the
standard deviation of the signal amplitude in
the displayed view of the screen. The standard
deviation is the measurement for the deviation
of a signal from its mean value. A low result indicates that
the values are close to the mean value. A higher result il-
lustrates that on average the difference between the va-
lues is greater.
DELAY: This mode measures the time de-
lay between the set measurement source and
the reference source. This mode searches for
the slope of the measurement source that is closest to
the time reference. Then, beginning from this point, it
searches for the nearest slope of the reference source.
This time difference indicates the measurement result. A
submenu (DELAY SETUP) allows you to select the setting
for measurement source, reference source and slopes.
PHASE: This mode measures the phase bet-
ween two slopes of two channels in the dis-
placed view of the screen (Phs). This mode
measures the relation of the time delay between the set
sources to the signal period of the measurement source.
This mode searches for the slope of the measurement
source that is closest to the time reference. Then, begin-
ning from this point, it searches for the nearest slope of
the reference source. The time difference and the signal
period indicate the measurement result in degrees. A sub-
menu (MEASUREMENT SOURCE/ REFERENCE SOURCE)
allows you to select the measurement source and the re-
ference source with the universal knob in the CURSOR/
MENU section.
COUNT + : This mode counts positive pulses
in the displayed view of the screen. A positive
pulse consists of a rising slope followed by a
falling slope. The mean value is calculated from the ampli-
tude of the measurement signal. A slope will be counted if
the signal runs through the mean value. A pulse that pas-
ses the mean value only once will not be calculated. The
measurement will only be applied to the selected channel.
COUNT – : This mode counts negative pulses
in the displayed view of the screen. A negative
pulse consists of a falling slope followed by a ri-
sing slope. The mean value is calculated from the ampli-
tude of the measurement signal. A slope will be counted if
the signal runs through the mean value. A pulse that pas-
ses the mean value only once will not be calculated. The
measurement will only be applied to the selected channel.
COUNT +/ : This mode counts signal chan-
ges (slopes) from Low Level to High Level in the
displayed view of the screen. The mean value
is calculated from the amplitude of the measurement sig-
nal. A slope will be counted if the signal runs through the
mean value. The measurement will only be applied to the
selected channel.
COUNT –/ : This mode counts signal changes
(slopes) from High Level to Low Level in the
displayed view of the screen. The mean value
is calculated from the amplitude of the measurement sig-
nal. A slope will be counted if the signal runs through the
mean value. The measurement will only be applied to the
selected channel.
TRIGGER FREQUENCY: This mode measu-
res the frequency of the trigger signal bases
on the period duration (f
Tr
). The source for the
measurement is the currently set trigger source. The fre-
quency will be determined with a hardware counter with a
high accuracy of 5 digits.
TRIGGER PERIOD: This mode measures the
duration of periods of the trigger signal (with a
hardware counter T
Tr
).
The automatic measurement results are displayed at the bot-
tom of the screen. If “n/a” is displayed, the measurement
is not applicable to the signal. For instance, this may be the
case for a voltage measurement on a POD because only lo-
gic states without voltage reference are displayed here. If
“?” is displayed, the display does not show a complete mea-
surement result. For instance, the period to be measured
may not display completely and can consequently not be
identied.
With the soft menu key CLEAR ALL the activated automa-
tic measurements will be switched off.
8.2.1 Statistics for Automatic Measurements
If automaticmeasurementfunctionsaredened,youcan
view statistics for these parameters on page 2|2 of the
AUTO MEASURE menu. The statistics allow you to evalu-
ate a periodic signal over a number of measurements. The
results (current value, minimum, maximum, mean value,
standard deviation and number of measurements) are
shown in table format in the display window. Statistics are
Fig. 8.2: Menu for the automatic measurements settings
The list of available sources only includes displayed channels
(possible sources are analog, digital and mathematical channels).