31
Subject to change without notice
Of course, the magnification is not restricted to a factor 50 as
mentioned in the example. The limit is given by the increasing
loss of trace intensity as the magnification is increased.
The manipulation of time delay requires a certain experience,
especially with complicated signal combinations which are
difficult to display. The recording of signal sections of simple
signals is, in contrast, from the beginning fairly easy. The time
delayed display is also possible in the dual channel, addition
and difference modes.
Attention:
The display may be in chopped DUAL mode with
DELAY operation in dual channel mode (DUAL). This is
the case when in SEARCH, a time base between 500ms/
div and 500µs/div is set, which automatically switches
in chopped DUAL mode.
The chopped DUAL mode is effective even if
subsequently the time base is switched to between
0,2ms/cm and 50ns in triggered or untriggered DELAY
operation. With highly expanded displays the channel
switching will be visible during a sweep (alternately
switching between channels I and II). One can then
switch to alternate DUAL mode. A renewed change in
the time base setting will again result in chopped
display but this can be overcome again.
AUTO SET
The instrument specific information regarding this function is
part of the section “Controls and Readout” paragraph
AUTO
SET (2)
. The following description is relevant for analog and
digital operation. In digital operation
AUTO SET
automatically
selects
REFRESH
signal capture if
ROLL
or
SINGLE
mode is
active. The signal to be displayed must meet the amplitude and
frequency requirements of automatic triggering, to enable a
useful automatic instrument setting.
As also mentioned above all controls are electronically selected
with the exception of the
POWER
and calibrator frequency
(
CAL 1kHz/1MHz
) pushbuttons as well as the FOCUS and TR
(trace rotation) control. Thus automatic signal related instrument
set up in Yt (time base) mode is possible. In most cases no
additional manual instrument setting is required.
Briefly pressing the
AUTO SET
pushbutton causes the
instrument to switch over to the last Yt mode settings
regarding
CH I
,
CH II
and
DUAL
. If the instrument was
operated in Yt mode, the actual setting will not be affected
with the exception of
ADD
mode which will be switched off.
At the same time the attenuator(s)
(VOLTS/DIV)
are
automatically set for a signal display height of approx. 6 div in
mono channel mode or if in
DUAL
mode for approx. 4 div
height for each channel. This and the following explanation
regarding the automatic time coefficient setting assumes that
the pulse duty factor of the input signal is approx. 1:1.
The time deflection coefficient is also set automatically for a
display of approx. 2 signal periods. The time base setting
occurs randomly if complex signals consisting several
frequencies e.g. video signals are present.
AUTO SET
sets the instrument automatically to the following
operating conditions:
• The input coupling is not affected while
AC
or
DC
is used,
but if
GD
was selected the last used input coupling (
AC
or
DC
) will be chosen.
• Internal triggering (channel I or channel II)
• Automatic peak (value) triggering
• Trigger level in electrical midrange position
• Y deflection coefficient(s) calibrated between 5mV/div and
20V/div
• A time base (deflection coefficient calibrated)
SEARCH
and
DELAY
time base mode switched off
• AC trigger coupling (
DC
trigger coupling unchanged)
• X x10 magnifier switched off
• Automatic X and Y position settings
• Trace and readout visible.
If
CURSOR
measurement is active,
AUTO SET
causes addi-
tional automatic settings. The restrictions already mentioned
must be taken into account:
Analog mode in combination with
∆∆∆∆∆
V
• automatic
CURSOR
supported voltage measurement.
• automatic assignment of the
CURSOR
lines to the signal,
which is used for triggering when
DUAL
mode is active.
Note
If no signal is applied or the trigger conditions can not be
met, the CURSOR line positions do not change.
The positioning accuracy depends on the signal frequency.
Digital mode in combination with
all CURSOR measurement modes
• automatic
CURSOR
supported voltage, time and frequency
measurement
• automatic assignment of the
CURSOR
lines to the signal,
which is used for triggering when
DUAL
mode is active.
Note
If no signal is applied or the trigger conditions can not
be met, the CURSOR line positions do not change.
Attention!
If a signal is applied with a pulse duty factor of ap-
prox. 400:1 or larger, an automatic signal display can
not be performed. The pulse duty factor causes too
low a Y deflection coefficient (sensitivity too high)
and too high a time deflection coefficient (time base
speed to slow) and results in a display in which only
the baseline is visible.
In such cases it is recommended to select normal triggering
and to set the trigger point approx. 0.5div above or below the
trace. If under one of these conditions the trigger indicator
LED is lit, this indicates the presence of a signal. Then both the
time coefficient and Y deflection coefficient should be reduced.
Please note that a reduction in intensity may occur, which could
result in a blank screen when the physical limits are reached.
STORAGE MODE ONLY
In contrast to analog mode, intensity reduction does not occur.
But it must be noted that pulses of less than 20ns width are
displayed with too small amplitude. This is because of too
few samples per pulse, as in 100MS/s condition (10ns
sampling interval) only 4 samples are taken.
Save/Recall
The instrument specific information regarding the controls and
their use are part of item
(12)
in section “Controls and
readout”.
The instrument contains a non volatile memory which can be
used by the operator to save 9 different instrument settings
and to recall them. This relates to all settings with the
exception of
FOCUS
,
TR
(trace rotation) and the calibrator
frequency pushbutton.
Auto Set - Save/Recall
