39
Subject to change without notice
31.1. AC DC
Pressing the pushbutton will switch from AC to DC or vice versa.
The mode selected will be shown in the readout following the
sensitivity setting: ~ is for AC and = is for DC.
31.1.1
DC coupling
The signal will be directly coupled, from the BNC connector via
the attenuator to the vertical amplifi er. The input resistance is
1 MΩ in all positions of the attenuator.
31.1.2
AC coupling
A capacitor is inserted between the BNC connector and the
attenuator, blocking the DC content of the signal and creating a
low frequency cut-off at approx. 2 Hz. This will affect the shape
and amplitude of signals with low frequency content. If the DC
content of the signal changes or the duty cycle of pulses the
capacitor will charge or discharge, this will cause a momentary
Y shift of the display.
31.2 Ground On Off
The pushbutton will either connect the amplifi er to the signal
or to ground. If set to Ground the readout will show a ground
symbol following the sensitivity setting, at the same place where
formerly the coupling was indicated. In the Ground position and
with automatic triggering a trace will be visible, this is handy
for setting the Y position of it e.g. to the screen centre without
disconnecting the signal. The readout will show a symbol ( ) for
0 V which will be close to the vertical centre line of the graticule,
it is the zero reference for any measurements. After switching
back to the signal its amplitude can now be determined with
respect to the formerly set zero reference.
31.3 Invert On Off
(unavailable in analog XY mode)
This pushbutton will alternate between not inverted or inverted
of the CH1 signal. The readout will indicate an inverted display
by placing a bar above the CH1. The trigger signal derived from
Ch1 will not be affected by an inversion.
31.4 Probe submenu
Pressing the pushbutton will open the ”CH1 probe“ submenu.
31.4.1
*1 - *10 - *100 - *1000
A selection of probe attenuation factors from 1 to 1,000 is pos-
sible. The value selected will be automatically taken into account
regarding the sensitivity indicated and measurements.
31.4.2
Auto
If Auto is selected HAMEG probes with automatic probe iden-
tifi cation connectors will be recognized by the scope and the
appropriate factor taken into account. The factor recognized
will be indicated following ”auto“.
Probes without that special connector will cause the display
”auto *1“ and treated as 1:1 probes.
31.5 Variable On Off
If activated VAR on the CH1 pushbutton
will be illuminated.
The readout will replace ”:“ by ”
>
“ (e.g. ”CH1
>
5mV“.) and this
also in any cursor measurements pointing out that the sensitivity
is uncalibrated.
The VOLTS/DIV-SCALE-VAR knob
will function as variable
which can change the sensitivity continuously between 1 mV/cm
to
>
20 V/cm.
VERT/XY pushbutton
This pushbutton switches the ”vertical“ menu on/off. This menu
allows to select the operating modes of the vertical amplifi ers.
C o n t r o l s a n d R e a d o u t
30.1.6
B trigger – OFF
Time base B will be started upon the end of the delay time set.
The delay time can be changed continuously in this mode which
can be watched on the intensifi ed sector of the time base A
display. The disadvantage here is that with very long delay times
jitter of the time base B display may crop up.
As time base B is not operated in the signal triggered mode
the controls for time base B trigger will be disabled resp. are
only for time base A.
30.1.7
A variable – On Off
If ”On“ was selected the TIME/DIV-SCALE-VAR knob
will
function as variable control for the time base A speed. Only in
time base A only mode this option will be available in the menu.
For a full description see ”28.1.3 Variable“.
30.1.8
B variable – On Off
If ”On“ was selected the TIME/DIV-SCALE-VAR knob
will
function as the time base B variable control. For a full descrip-
tion see ”28.1.3 Variable“.
30.1.9
Holdoff …%
In this mode the hold-off time may be selected from 0 to 100 %
with the INTENS knob
. Values
>
0 extend the waiting time
after a sweep before a new one can start and decrease thus the
repetition rate which may darken the display. This is indicated
by the HOLD OFF-LED
lighting up. The hold-off time is only
valid for time base A.
Further information can be found in the section ”Hold-off adjust-
ment“ in the chapter ”Triggering and time bases“.
30.2. DSO mode
In the ”Zoom“ menu the following time base functions are
available:
30.2.1
Off
In ”Zoom Off“ condition only time base A is active. The readout
will thus only show ”A...“ in the top left corner. The speed can
be set with the TIME/DIV-SCALE-VAR knob
.
30.2.2
Search
Part of the time base A display will be intensifi ed and this
portion will also be displayed expanded over the full screen.
With the HORIZONTAL knob
the intensifi ed sector and the
expanded display can be shifted provided that the pushbutton
X-POS DELAY
is illuminated which means ”Delay“. The
length of the intensifi ed sector is determined by the speed of
the Z time base.
The Y position of both displays is identical so they are written one
over the other. In order to separate them for better readability
an artifi cial Y offset may be added to the Z time base display.
Press the pushbutton CH1/2-CURSOR-MA/REF-ZOOM
to
call the menu ”Pos./Scale“.
Then press the function pushbutton ZOOM. Now the POSITION
1 knob will function as Y position control for time base Z. As this
only makes sense in SEARCH mode it is unavailable in others.
30.2.3
Zoom only
Only the Z time base will be displayed. The readout will hence
only show ”Z...“ in the top left corner. The TIME/DIV-SCALE-VAR
knob affects only time base B.
CH1 pushbutton
This pushbutton opens the CH1 menu which contains the follo-
wing options referring to CH1
resp. to the signal on CH1.
