38
Subject to change without notice
22.1 Edge
/
VideoTrigger
22.1.1
CH1
Conditions: Analog or digital mode, ”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)“.
22.1.2
CH2
Conditions: Analog or digital mode, ”Edge“ or ”Video“ selected.
CH2 will then be the trigger source, no matter whether it is
displayed or not.
Readout: ”Tr:CH2, (Slope), Filter (TV).“
22.1.3
Alt. 1/2
Conditions: Analog mode, ”Edge“ Triggering“.
Alternate triggering with the signals from channels 1 and 2 as
described in the section ”Alternate Trigger“ of chapter ”Trig-
gering 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 pos-
sible in conjunction with alternate dual channel operation. If
previously dual trace chopped mode was selected (VERT/XY
pushbutton
32
)
>
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 selec-
ted again.
Readout: ”Tr:alt, Slope, Filter“.
22.1.4
External
In this mode the trigger signal comes from the external trigger
input (AUXILIARY INPUT).
Readout: ”Tr:ext, Slope, Filter“.
22.1.5
AC Line
The trigger signal is taken from the line (mains supply) which feeds
the scope. See also the section ”Line triggering“ in the chapter
”Triggering and time bases“. Readout: ”Tr:alt, Line, Slope“.
23
TRIG’d display
(not in XY mode)
This LED will light up if the time base receives a signal suited
for triggering at the instruments present trigger settings. It
depends upon the trigger signal whether the LED will just blink
or remain illuminated.
24
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
20
). The light indicates that the screen will
remain dark as long as there is not sufficient trigger signal.
25
HOLD OFF display
(Analog mode only)
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
30
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“.
26
X-POS DELAY
(pushbutton)
no function in FFT mode
This pushbutton allows you to change the function of the HO-
RIZONTAL knob
27
.
26.1 Analog mode
The pushbutton signals the actually selected function in accor-
dance with the front panel lettering:
dark:
X position control
green: Delay time control
26.1.1
X POS
If the pushbutton is dark the HORIZONTAL knob
27
functions as
X position control, i.e. it moves the signal display horizontally.
The position control is especially useful when the magnifier
(MAG. x 10
29
) is switched on. The magnifier will magnify the
display 10 times around the screen centre. Using the POS
control, the portion of the signal to be studied can be shifted
on the screen.
26.1.2
DELAY
In order to change the function of the HORIZONTAL knob
27
to
”Delay“ proceed as follows:
Press the HOR VAR pushbutton
30
which will present the ”Time
base“ menu, select ”Search“ or ”B only“, then the function of the
knob will be changed if the pushbutton is depressed. It will light
up to show that the knob is now the delay time control.
In ”Search“ mode both traces (time base A and B) alternate.
Unlike the former time base ”A only“ mode, a sector with hig-
her intensity is visible on the A trace. This sector can be moved
continuously by the delay time control. The time between the
A trace start and the beginning of the intensified sector is the
delay time. This information is also displayed in the readout (”Dt:
…“) and is an aid to find the position of the intensified sector
which may be very small. If time base ”B only“ is chosen the
intensified sector is no longer visible, but the DELAY function
still can be used.
Without activated ”B Trigger“ function, the B time base will be
started after the A time base delay time ”elapsed“.
26.2 Digital mode
The pushbutton will indicate the actual function in accordance
with the front panel lettering:
dark = Post- and Pre Trigger control (moves the trigger point
in horizontal direction).
green = Delay time control for horizontal Zoom position=
shift.
26.2.1
X-POS delay
If the pushbutton is dark the HORIZONTAL
27
knob functions as X
position control of the trigger time, i.e. it moves the trigger point
symbol horizontally. This allows display of signal portions before
and after the trigger, called Pre Trigger and Post Trigger. If the
trigger point symbol is located on the screen centre the readout
will show ”Tt:0s“, hence the trigger time indication is always re-
ferred to the screen centre. Values with a positive sign are Post
Trigger times, those with a negative sign Pre Trigger times.
If the X POS DELAY pushbutton is depressed the ”Hor.Knob“
menu will be called, it contains the following options:
1
st
Centre: Pressing the function pushbutton ”Center“ will set
the trigger time to the screen centre ”Tt:0s“ which is the
standard setting.
2
nd
Coarse On Off: changes the speed of the HORIZONTAL knob
27
.
C o n t r o l s a n d R e a d o u t
