Advanced Features
Trigger This consists of a 'graphical' menu which controls
the 4070 trigger system and allows easy setting of the
trigger processor.
Display This menu controls how the traces are acquired and
in
what format they are subsequently displayed.
Help A brief menu giving some information on various
aspects of the instrument's operation.
Save and Recall Setup
Up
to four control setups on the 4070
can be retained
in
the backup memory for future
recall. These save and recall features can be accessed
with this menu. The status menu allows the saved
setups to be viewed, see above.
Plot The various methods of plotting captured traces can
be set using this menu.
Once set up, simply press the
Plot button on the front panel to produce a hard
copy.
1/0 Interfaces This menu allows the controllable features of
the
GPIB and RS423 interfaces to be set. These
include such things as the
GPIB address and RS423
baud rate.
TV and
Special Functions The additional trigger couplings,
TV line and TV frame, can be selected through this
menu. In addition, the time and date may also be set
for use on the plot outputs.
Controlling the Menus
The menus consist
of
a number
of
rows of text each of which
is
in line with one of the numeric buttons at the side of the
display.
On
some of the lines you
will
notice there are
characters in inverse video, these show which option has
been chosen. In some cases, where
the
number of options
is
large, only the selected one
is
shown. Again, you
will
notice
that some
of
the inverse characters are flashing, this indi-
cates the active line. The entry on this line may be changed
by
the the relevant numeric button
or
the vertical datum
paddle.
Horizontal Datum can be used to select the active line
in
the
current menu. This
is
in addition to using the numeric
buttons at the side
of
the display.
Vertical Datum can be used to select options on the active
line
or
skip over digits
in
number entry mode (see
later).
2.2 STATUS
MENU
This menu allows the horizontal, vertical and trigger set-
tings of the instrument to be viewed. A typical display
is
shown
in
Figure 2.2.1.
VIEW
SETUP There are five possible setups on the 4070,
the four held
in
the backup store (see Section 2.6) and the
current setup obtained from the front panel buttons and
paddles. The setup presently being displayed
is
indicated
by
the inverse video characters after the words 'VIEW
SETUP'.
Examples:
VIEW SETUP
CURRENT
VIEWSETUP4
Section 2
The status menu
is
showing
the present instrument
setup.
The setup
in
memory
number 4
is
being dis-
played.
To view a different setup simply press button number
1.
Each press steps through the five options:
CURRENT,
1,
2, 3, and
4.
After 4 has been selected a fi::ther press
will
return the choice to
CURRENT.
Mode: There are four display modes: Roll, Refreshed, Pre-
Trigger Roll and XY. The mode
in
the displayed setup
is
indicated
by
the abbreviations given below:
Roll
Refreshed
Pre-Trigger Roll
XY
Roll
Re fr
Pretrig Roll
X-Y
The four modes and how they operate are described under
the display menu, Section 2.4.
Channel Sensitivity
The input sensitivity of the input channels
is
shown in volts
per division. The range
is
2mV to
SY
per division.
If
add
mode
is
selected, as in the example in Fig2.2.1, a 'plus' sign
is
shown after the attenuator range for channel
1.
If
invert
is
selected a 'minus' sign
is
shown before the attenuator
range.
Timebases
The sweep rate of the two timebases, TBA and TBB,
is
shown in s, ms,
µ.s
or
ns
per
di'
is
.on. Following this
is
the
trigger 'delay
by
time' setting.
If
the time delay
is
positive
this
is
given
ins,
ms,
µ.s
or
ns as appropriate. With negative
time delays the figure
is
given as a percentage
of
pre-trigger:
0% places the trigger point at the left hand edge
of
the
screen,
50%
in
the middle and 98% at the right hand edge.
Triggering
Under each timebase line
is
a short description
of
how the
sweep
is
started. This
is
a representation
of
the trigger con-
figuration diagram
in
words, see Section 2.3 for more
details.
The bottom two lines show the two trigger channels' source,
coupling and trigger level settings. The choices
of
source
and coupling are detailed in Section 1.4.
Note: The
trigger
level
cannot
be directly related
to
a
position
on
the screen, so the figure
shown
is
only
rep-
resentative
of
the
trigger
level
compared
with its setta-
ble range.
45
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