Beamfinder; Trace Alignment; Readout Display - Tektronix 7140 Instruction Manual

Operating Instructions-7104
BEAMFINDER
The BEAMFINDER
helps to locate
a display that
overscans the crt
viewing area
vertically and/or
horizontally . When the BEAMFINDER button is pressed,
the display is compressed and defocused within the
graticule area . To locate and reposition an overscanned
display, use the following procedure :
1 . Press the BEAMFINDER pushbutton . While the display
is compressed adjust the vertical and horizontal position
controls to center the display. Change the vertical and
horizontal deflection factors until the vertical deflection is
about four divisions high and the horizontal deflection is
about six divisions wide (the horizontal deflection needs
to be reduced only when operating in an X-Y mode).
2. Release the BEAMFINDER pushbutton; the display
should remain within the graticule area .
TRACE ALIGNMENT
The TRACE ROTATION control allows the trace to be
aligned with the horizontal graticule lines. To set the
control, position the trace to the center horizontal line
and adjust the TRACE ROTATION control so that the
trace is parallel with the center horizontal graticule line .
LEFT VERT
RIGHT VERT A HORIZ
B HORIZ
CHANNEL1
CHANNELI CHANNELI
CHANNELI
. . . . . . .
90-
I
a
I
ox~ . . . . . . . . . .
. . . . . . . . . . . .
LEFT VERT RIGHT VERT
A HORIZ B HOR12
CHANNEL2 CHANNEL2
CHANNEL2 CHANNEL2
1675-8
Figure 2-4. Location of readout on the crt identifying the
originating plug-in and channel.
READOUT DISPLAY
released, the readout display from this plug-in channel is
The Readout System provides an alphanumeric display of
again displayed . Circuitry may also be provided in the
information on the crt along with the analog waveform
amplifier unit to produce a noticeable change in the
dis la
The information displayed by the Readout
analog waveform display to identify the associated trace
P Y~
when the "identify" button is pressed (see the plug-in
System is obtained from the plug-in units installed in the
unit instruction manual for details) .
plug-in compartments .
The readout information from each channel of a plug-in
Readout Intensity
unit is called a word . Up to eight words of readout
The READOUT control determines the intensity of only
information can be displayed on the crt (two channels
the readout portion of the display, independently of the
from each of the four plug-in compartments) . The
other traces . The Readout System is inoperative when
location of each readout word is fixed and is directly
the READOUT control is in the fully counterclockwise
related to the plug-in unit and channel from which it
OFF position . This may be desirable when the top and
originated . Figure 2-4 shows the area of the graticule
bottom divisions of the graticule are to be used for
where the readout from each plug-in unit and/or
waveform display or
when the trace interruptions
channel is displayed. Notice that the readout from
necessary to display characters interfere with the
channel 1 of each plug-in unit is displayed in the top
waveform display.
division of the graticule and the readout from channel 2
is displayed directly below in the bottom division of the
Readout Modes
graticule. Usually, the readout information for plug in
units and/or channels, which are selected by the mode
The READOUT control determines the operating mode of
switches, appear in the readout display. (Some special
the Readout System . With the READOUT control set to
purpose plug-in units may over-ride the mode switches
free run (out of OFF or PULSED detent positions) the
to display readout even though the compartment is not
Readout System operates continuously, interrupting the
selected for display.)
crt display at random (for about 20 microseconds) in
order to write each character on the crt. With the
READOUT control set to the PULSED position, the
Readout Identify Readout System operates in a triggered mode ; one
An "Identify" feature is provided by the Readout System
complete frame (up to eight words) of readout is
to correlate the readout word with the originating plug-in
displayed. The
+ GATE or EXT switch
determines
unit and channel (amplifier units only). When the
whether readout is displayed at the end of the + GATE
"identify" button of an amplifier unit is pressed, the word
or when an external signal is applied to the rear-panel
IDENTIFY appears in the readout location allocated to
GRATICULE/READOUT SINGLE SHOT input . The + GATE
that plug-in and channel . Other readout words in the
switch selects whether A gate or B gate triggers the
display remain unchanged. When the "identify" button is
readout .