37
Subject to change without notice
28.1.2
Time base B time/cm selection
This function is active if in the ”Time base“ menu (HOR
push-button) SEARCH or B ONLY was selected and the option
”B variable On Off“ was set to Off.
Turning the control CCW will decrease, turning it CW will increa-
se the time base speed. The speed can be selected between 20
ms/cm.. 50 ns/cm in a 1-2-5 sequence and will be calibrated.
The readout will show the speed (e.g. ”B:50ns“).
The time base B allows to display portions of the time base
A display on an expanded time base scale. This implies that
the speed of TB B must always be greater than that of TB A.
Therefore with the exception of 50 ns/cm TB B can not be set
to the same speed as TB A.
Further information is available in the section ”Time base B
(2
nd
time base/Delay/Triggering“ (Analog mode) in the chapter
”Triggering and time bases“.
28.1.3
Variable
The TIME/DIV–SCALE–VAR control may also be used to change
the time base speed continuously but uncalibrated. VAR will light
up on top of the HOR
pushbutton in order to warn that the
time base is uncalibrated and the knob has now that function.
In order to arrive at that function press HOR
which calls
the TIME BASE menu. Depending whether time base A or B is
selected either ”A variable On Off“ or ”B variable On Off“ will
be shown. The function pushbutton can then be used to select
On/Off.
In order to point out that the time base is now uncalibrated
the readout will replace ”:“ by ”
>
“ preceding the time/cm. (e.g.
”A
>
500ns“ and ”B
>
200ns“). Also the results of cursor time/pe-
riod measurements will be marked that way.
28.2 DSO mode
28.2.1
ZOOM OFF (A time base time/cm selection)
Select the menu ”Zoom“ by pressing HOR
and then ”Off“ in
order to set the function of the knob TIME/DIV–SCALE–VAR to
time base A speed as in analog mode. If ”Zoom Off“ is active
always the whole memory will be displayed.
Turning the control CCW will decrease, turning it CW will
increase the time base speed. Depending on the signal captu-
re/display the time base can be set from 50 s/cm to 5 ns/cm in
a 1-2-5 sequence (e.g. ”A:50ns“) and will be calibrated. There
is no variable function as in analog mode.
28.2.2
Search–Zoom only (Zoom time base speed selection)
One of the functions SEARCH or ZOOM ONLY may be selected in
the ZOOM menu after pressing HOR
. ”Zoom Off“ is equivalent
to time base A in analog mode. With ”Zoom only“ a portion of the
display in Zoom ”Off“ can be expanded over the whole screen.
This is possible because there is a very large memory for signal
capture/display. The ”Zoom Off“ display will present the whole
memory contents. With SEARCH both the ”Zoom Off“ and the
expanded ”Zoom only“ displays will be visible. With ”Zoom only“
only the expanded display will show up.
The Zoom time base speed will be indicated in the readout ”Z:...“
and is calibrated. Turning the knob CCW will decrease, turning
it CW will increase the time base speed. This can be selected
from 20 ms/cm to 5 ns/cm in a 1-2-5 sequence. The maximum
expansion is 50,000 times (”A:10ms“ and ”Z:200ns“.)
MAG pushbutton
In analog mode only: pressing this pushbutton will turn on the
x 10 magnifi er. No menu will be shown.
C o n t r o l s a n d R e a d o u t
intensifi ed 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 DSO mode
The pushbutton will signal the actual function in accordance
with the front panel lettering:
dark:
The knob functions as X position control.
green:
The knob functions as delay time control.
26.2.1
X-POS
If the pushbutton is dark the HORIZONTAL
knob functions
as X position control of the trigger time, i.e. it moves the trigger
point symbol horizontally. This allows to display signal portions
before and after the trigger, called Pre-Trigger and Post-Trig-
ger. If the trigger point symbol is located on the screen centre
the readout will show ”Tt:0s“, hence the trigger time indication
is always referred to the screen centre. Values with a positive
sign are Post-Trigger times, such 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.
26.2.2
DELAY
This pushbutton will be illuminated if the TIME BASE menu
was called with the HOR
pushbutton and SEARCH or
B ONLY selected. The HORIZONTAL
knob can then be used to
select a portion of the time base display which is to be displayed
expanded in time.
In SEARCH mode the normal and the expanded displays are
displayed simultaneously. The expanded portion of the signal
will be shown on the normal display as an intensifi ed sector.
The length of this sector is dependent upon the setting of the
2
nd
”Z“ ,time base which is shown in the readout as ”Z...“ and
is equal to the run time of the Z time base.
HORIZONTAL knob
The various functions of this knob depend on the operating mode
and are described under X-POS DELAY
pushbutton.
TIME/DIV.–SCALE–VAR knob
This knob is normally used as the time base speed selector, but
has also other functions dependent on the operating mode. In
XY mode this control is disabled.
28.1 Analog mode
28.1.1
Time base A time/cm selection
This function is active if in the ”Time base“ menu (HOR
pushbutton) ”A only“ was selected and the option ”A variable
On Off“ was set to Off.
Turning the knob CCW will decrease, turning it CW will increa-
se the time base speed. The time base speed may be chosen
between 500 ms/cm... 50 ns/cm in a 1-2-5 sequence and will be
calibrated. The readout will show the setting (e.g. ”A:50ns“).
