29
Subject to change without notice
C o n t r o l s a n d R e a d o u t
displayed or not.
Readout: ”Tr:CH2, (Slope), Filter (TV).“
18.1.3
Alt. 1/2
Conditions: EDGE-Triggering. Alternate triggering with the
signals from channels 1 and 2 as described in the section ”Al-
ternate Trigger“ of chapter ”Triggering and time bases“. Please
note that in this trigger mode the apparent time relationships
between the two signals on the screen are meaningless and
misleading, the relative position of the two signals depends only
on their shape and the trigger level selected.
In dual channel mode (DUAL) alternate triggering is only possible
in conjunction with alternate dual channel operation. If previously
dual trace chopped mode was selected (VERT/XY
28
pushbutton)
>
DUAL chop) it will be automatically changed to alternate mode
when alternate triggering is selected. After ”Alt. 1/2“ is turned off
dual trace chopped mode may be selected again.
Readout: ”Tr:alt, Slope, Filter“.
18.1.4
External
In this mode the trigger signal comes from AUXILIARY INPUT
33
). Readout: ”Tr:ext, Slope, Filter“.
18.1.5
AC Line
The trigger signal is taken from the line which feeds the scope.
See also the section ”Line triggering“ in the chapter ”Triggering
and time bases“.
Readout: ”Tr:alt, Line, Slope“.
19
TRIG’d display
(not in XY-mode)
This LED will light up if the time base receives a trigger signal.
It depends upon the trigger signal whether the LED will just
blink or remain illuminated.
20
NORM display
This display will light up provided ”Auto“ triggering was not
selected. The mode can be selected in the ”Trigger“ menu called
by pressing (MODE
16
). The light points out that the screen will
remain dark as long as there is no suffi cient trigger signal.
21
HOLD-OFF display
This display will light up if the hold-off time was set to
>
0% in
order to indicate that the longer than minimum hold-off time
may cause a lower rep rate of the time base and thus a darker
display. Setting the hold-off time requires pressing the HOR
VAR pushbutton
26
which calls the menu ”Time base“. Only the
time base A hold-off time may be changed.
See the section ”Hold-off time setting“ in the chapter ”Triggering
and time bases“.
22
X-POS DELAY
(pushbutton)
This pushbutton allows to change the function of the HORI-
ZONTAL knob
23
.
The pushbutton signals the actually selected function in accor-
dance with the front panel lettering:
dark:
X-position
control
green:
Delay time control
22.1
X-POS
If the pushbutton doesn‘t lit the HORIZONTAL-knob
23
functions
In BOTH MODE both slopes will trigger. This allows e.g. the
display of eye diagrams.
17.2 Menu: Video
In order to reach the menu ”Video“ proceed as follows:
Press MODE
16
to open the ”Trigger“ menu, select ”Video“, then
press the FILTER pushbutton
17
. Further information can be
found under ”Video“ (TV signal triggering) in the chapter ”Trig-
gering and time bases“ and in the instrument specifi cations.
The following settings are available:
17.2.1
Frame, Line.
Depending on the setting chosen triggering will be on frame
or line sync pulses. The selection will also affect other menu
items.
Readout:
”Tr:Source, TV“.
17.2.1.1
Frame
–
ALL:
In this mode the sync pulses of each half frame can
trigger.
–
Even:
In this mode only the sync pulses of even half frames
can trigger.
–
Odd:
In this mode only the sync pulses of odd half frames
can trigger.
17.2.1.2
Line.
-
All:
In this mode all line sync pulses can trigger.
-
Line No:
The line number with its line pulse that is used for
triggering can be selected with the INTENS knob
2
.
–
Line min:
One pushbutton operation will be suffi cient to
switch back to the lowest possible line number.
17.2.2
Norm
The pushbutton allows the selection of the US standard of 525
lines and 60 Hz or the European standard with 625 lines and
50 Hz. With any change of standard the line number will be
automatically changed, too.
17.2.3
Polarity
Composite video signals may have both polarities. Selection of
the right polarity is vital as the scope should be triggered by the
sync pulses and not the video content.
Positive polarity is defi ned by the video content being more
positive than the sync signals and vice versa.
If the polarity was wrongly selected there will be no triggering
at all, an untriggered display or no signal capture.
18
SOURCE
(pushbutton)
Depressing this pushbutton will call various menus depending
on the previously selected mode (MODE
16
pushbutton): Edge
and Video. In XY mode the pushbuttons: MODE
16
, FILTER
17
,
SOURCE
18
are disabled as XY displays can not be triggered.
18.1
Edge-/Video-Trigger
In the ”Trigger SOURCE“ menu the source is selected from
which the trigger signal is to be taken. The options depend on
the actual mode of the scope.
18.1.1
CH1
Conditions: EDGE or VIDEO selected.
CH1 will then be the trigger source, no matter whether it is
displayed or not.
Readout: ”Tr:CH1, (Slope), Filter (TV)“.
18.1.2
CH2
Conditions: EDGE or VIDEO selected.
CH2 will then be the trigger source, no matter whether it is
