30
Subject to change without notice
24.2
Time base B time/cm selection
This function is active if in the ”Time base“ menu (HOR VAR
pushbutton
26
) ”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 in-
crease 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“ in the chapter ”Triggering
and time bases“.
24.3
Variable
The TIME/DIV–VAR control may also be used to change the time
base speed continuously but uncalibrated. ”VAR“ will light up on
top of the HOR VAR pushbutton
26
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 VAR
26
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.
25
MAG x10
(pushbutton)
Pressing this pushbutton will turn on the x 10 magnifi er. No
menu will be shown.
If ”x10“ is illuminated on the MAG pushbutton the magnifi er is
activated. The adjusted time/cm will be shown in the top left
readout.
Depending on the time base mode turning on the magnifi er will
have these effects:
25.1 ”Time base A only“
The display will be expanded around the screen centre by a
factor of 10, the time/cm adjusted accordingly.
25.2 ”Search“ (A and B times bases alternated)
The time base A speed will not be affected. The time base B
speed will be increased by a factor of 10, hence the time base
B display will be expanded 10-fold in X-direction.
25.3 ”B only“:
The time base B speed will be increased by a factor of 10 and
the display hence expanded 10-fold in X-direction.
26
HOR VAR
(pushbutton)
This pushbutton will open the ”Time base“ menu the contents
of which depends on the operating mode selected.
26.1 A only
Only the time base A will be operative. The readout will thus only
show ”A...“ in the top left corner. The TIME/DIV-VAR knob will
set the time base A speed. With the MAG x10 pushbutton the
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 is not lit the HORIZONTAL-knob
23
functions
as X position control, i.e. it moves the signal display horizon-
tally.
The position control is especially useful when the magnifi er
(MAG x10
25
) is switched on. The magnifi er will magnify the
display 10 times around the screen centre, with the control the
portion of the signal to be studied can be shifted on-screen.
22.2
DELAY
If alternate A and B time base or B only time base mode is
present, the X POS DELAY pushbutton can be used to switch
over the function of the HORIZONTAL knob
23
from X position to
DELAY control. On condition DELAY is activated, the pushbutton
lights. Then the HORIZONTAL knob
23
can be used to determine
a delay time which must elapse before the B time base is star-
ted. The delay refers on the A time base start and is indicated
by the readout display “Dt:....”. If alternate time base mode (A
and B time base active) is present there is also an intensifi ed
sector visible on the A time base trace. It`s start position (left)
also indicates the delay time.
For further information please refer to item 26 (HOR VAR
pushbutton).
23
HORIZONTAL knob
The various functions of this knob depend on the operating mode
and are described under X-POS DELAY
22
pushbutton.
24
TIME/DIV.–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.
24.1
Time base A time/cm selection
This function is active if in the ”Time base“ menu (HOR VAR
pushbutton
26
) ”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“).
C o n t r o l s a n d R e a d o u t
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
FAX 781.665.0780 - TestEquipmentDepot.com
