36
Subject to change without notice
18.2 Respect
18.2.1
“Respect Tr“ indicates that the trigger signal is used for
measurement. If e.g. the signal applied at channel 1 serves
as trigger signal (internal triggering) the displayed measuring
value is related to this signal.
18.2.2
CH1 or CH2 indicate the trigger signal source. If the
INTENS knob
2
symbol is displayed, the source can be chosen
with the INTENS knob
2
.
18.3 Off
Pressing the function key “Off“ switches AUTO MEASURE and
the menu display off.
The menu can be left without switching AUTO MEASURE off by
pressing the MENU OFF pushbutton
43
.
19
LEVEL A/B – FFT Marker
(knob)
The knob function depends on Yt or FFT mode.
19.1 Yt mode
The LEVEL control allows you to set the trigger level, i.e. the
voltage or signal level, which will generate a trigger to start
the time base whenever the signal passes that level. In most Yt
modes the readout will show a symbol the vertical position of
which indicates the signal point which will trigger. The trigger
symbol will be ”parked“ on the second graticule line from the
bottom in those modes where there is no direct relationship
between trigger signal and trigger point.
In normal trigger mode the LEVEL control will move the trigger
symbol anywhere. In automatic peak triggering mode (automatic
trigger (AUTO) in combination with AC trigger coupling), the level
can only be selected between the signal’s peak values; without
signal the trigger symbol can not be moved. The movement of
the trigger symbol is vertical only. The range of this symbol is
limited so that it will not overwrite other readout information.
As soon as the trigger symbol leaves the graticule its form will
change, this change indicates in which direction the trigger
symbol left the graticule.
Analog mode only: Depending on the time base mode the LE-
VEL control will affect the time base A or B triggering. Press
the HOR VAR pushbutton
30
in order to select the time base
mode in the ”Time base“ menu. In ”Search“ mode (alternate
time base mode) the last trigger level setting for time base A
will remain valid (graticule left) if time base B is switched to
triggered mode. (Menu ”Time base“: set B trigger to positive or
negative slope). Thereafter the LEVEL A/B control will control
the time base B trigger, a second trigger point symbol will be
shown and marked with ”B“.
19.2 FFT mode
The FFT control will move the marker („X“ Symbol) over the
frequency range. The marker follows the displayed spectra.
The readout additionally displays the frequency on which the
marker is set (“MX:xxxMHz“) and the level („MY:xxxdB“ respec-
tively ”MY:xxxV“).
20
MODE
(pushbutton)
Preliminary note!
The pushbuttons MODE
20
, FILTER
21
and SOURCE
22
refer
to the trigger unit. In XY mode these pushbuttons are without
effect as XY displays are untriggered.
Pressing this pushbutton will open the ”Trigger“ menu, where
Auto, Normal, Single (sweep triggering) can be selected. Choo-
sing ”Slope“ will allow trigger on any signal shape. For video
signals select ”Video“ and press the FILTER pushbutton
21
in
order to find a choice of special trigger modes for composite
video signals.
In digital mode also ”Logic“ will be offered, allowing trigger
on logic signals. The explanations can be found in: FILTER
21
and SOURCE
22
.
In XY mode the pushbuttons MODE
20
, FILTER
21
and SOURCE
22
are disabled as there is no triggering in XY mode.
20.1 Auto (trigger)
Automatic triggering (Auto) is active if the NORM display
24
is
not illuminated. In ”Auto“ the analog time base or signal capture
(digital mode) will be periodically started even if there is no
signal or when no triggers are generated because the settings
are incorrect. Signals of
<
20 Hz can not be triggered as the
automatic start will have occurred before the signal arrived.
Automatic triggering is possible with or without peak detection.
The LEVEL A/B
19
control will be active in both modes.
In peak detection mode the range of the level control is limited
to the peak to peak voltage of the signal. Without peak detection
any level can be set. If the trigger level is set such that no trig-
gers are generated the automatic triggering will nevertheless
start the time base. The signal will thus remain visible but will
be untriggered.
Automatic peak triggering is active if automatic triggering
(MODE: AUTO) is chosen in combination with the trigger FILTER
setting AC (trigger coupling). The active mode will be shown
by the behaviour of the trigger point symbol when turning the
LEVEL knob.
20.2. Normal (trigger)
If the NORM LED
24
lights up, normal triggering was selected.
In normal trigger mode both the peak detection and the au-
tomatic time base start will be disabled. Hence if there is not
sufficient trigger signal, the screen will remain dark in analog
mode. In digital mode signal capturing will also stop unless the
roll mode was selected.
In normal trigger mode there is no lower frequency limit for
signals. Without trigger, the last signal capture will be displayed
as long as the oscilloscope settings are not changed.
20.3 Single (sweep
/
capture)
In single sweep/capture mode the time base selected will accept
only one trigger for one sweep/capture after it was armed. The
NORM LED will light up, Auto triggering is disabled and the
RUN/STOP lit periodically.
For further information about the precise operation see RUN/
STOP pushbutton
6
description.
21
FILTER
(pushbutton)
Preliminary note!
The pushbuttons MODE
20
, FILTER
21
and SOURCE
22
refer
to the trigger unit. In XY mode these pushbuttons are without
effect as XY displays are untriggered.
After this pushbutton is depressed it will depend on the settings
chosen in MODE
20
(Edge, Video, Logic) which menu will be
offered. In XY mode the pushbuttons: MODE
20
, FILTER
21
and
SOURCE
22
are disabled as XY displays can not be triggered.
21.1 Menu: Slope
The menu ”Edge“ will appear if ”Edge“ was selected in the ”Trig-
ger“ menu to be called with MODE
20
pushbutton and after the
C o n t r o l s a n d R e a d o u t
