Operating lnstructions—7B53A/7B53AN Operators
20. Rotate the
DLY'D TRIG LEVEL control counter
clockwise
out of switch detent
for
a triggered delayed
sweep.
With
the DLY'D
TRIG SLOPE, COUPLING, and
SOURCE
switches set to (+), AC, and
INT; rotate the
DLY'D TRIG
LEVEL control for a stable intensified
portion of
display. Rotate the
DELAY TIME MULT dial
and
note that the
intensified portion of display does not
start
at the
completion
of the delay time
(determined by
the
settings of the
TIME/DIV OR
DLY
TIME switch and
the
DELAY TIME MULT dial), but waits for the next
trigger pulse.
21.
Press the DLY'D
Time/Division
switch in for the
DLY'D
SWP Display Mode.
Rotate
the
DLY'D TRIG
LEVEL
control for a stable delayed sweep display (oscillo
scope Intensity may need to be varied).
Check that
a stable
delayed sweep
display can be
obtained
with the DLY'D
TRIG
COUPLING switch set to AC and DC for both + and
-
positions of the
SLOPE switch (DLY'D
TRIG LEVEL
control may
be adjusted as necessary for
a
stable delayed
sweep
display).
22. Change the DLY'D TRIG
SOURCE switch to EXT.
Connect the
indicator oscilloscope Calibrator signal to the
DLY'D TRIG
IN connector. Set the oscilloscope Calibrator
for
0.4 volt at
1 kilohertz and adjust the vertical Volts/
Division switch
for about 4 divisions of display. Check that
a
stable
delayed sweep display can be obtained with the
DLY'D
TRIG COUPLING switch
set to AC
and DC
for
both
the + and - positions of the SLOPE switch (DLY'D
TRIG
LEVEL
control may be adjusted as necessary
for a
stable
delayed sweep display).
GENERAL
OPERATING
INSTRUCTIONS
Pushbutton
Switch
Logic
The MODE,
COUPLING,
and SOURCE pushbuttons of
the
MAIN TRIGGERING switches are arranged in a
sequence
which places the most-often used position at the
top
of each series of
pushbuttons. With this arrangement, a
stable
display can usually be obtained by pressing the top
pushbuttons:
AUTO, AC, and INT. When an adequate
trigger
signal is applied, the unit is triggered as indicated by
the
illuminated
TRIG'D light,
with the correct setting of
the
LEVEL control and SLOPE switch. If the TRIG'D light
is not
on, the
LEVEL control
is at a setting outside the
range
of
the
trigger signal applied to this unit
from the
vertical unit,
the trigger
signal is inadequate, or its
frequency
is
below the lower frequency limit of the AC
COUPLING
switch position.
If the desired
display is not
obtained with
these buttons pushed in, other
selections
must
be
made. Refer to the following discussions or the
instruction
manuals
for the associated oscilloscope and
vertical
unit for more information.
Triggered
Light
The
TRIG'D
light conveniently indicates the condition
of
the triggering circuits. If the MAIN TRIGGERING
controls
are correctly
set and an adequate trigger signal is
applied, the
TRIG'D light is on. Under certain conditions,
the TRIG'D
light may
be off, indicating that
the sweep is
not
triggered. The cause could be a misadjusted LEVEL
control,
incorrectly set COUPLING or SOURCE
switches,
low
trigger signal amplitude, or
a triggering signal repetition
rate
outside the
acceptable frequency range. This light can
be used
as
a general
indication of correct
triggering.
It is
particularly
useful when setting up the trigger circuits when
a
triggering signal is available without a display on the CRT.
Main
Trigger Mode
The
pushbuttons
located under the
MODE
title select
the
mode
in
which the main sweep is triggered.
AUTO.
When
the
AUTO pushbutton is pressed, a
triggered display is
presented whenever
an
adequate trigger
signal
is applied and the LEVEL control and SLOPE switch
are
correctly
set. The TRIG'D light indicates when the
display
is triggered.
When
the trigger repetition rate is below about 30 hertz,
outside the
frequency range
selected by the COUPLING
switch,
or when
the trigger signal is inadequate, the sweep
free-runs
at the sweep rate indicated by the TIME/DIV or
DLY
TIME
switch (TRIG'D light off). When an adequate
trigger
signal
is
again applied, the free-running condition
ends and a
triggered display is presented. The sweep also
free-runs
when
the LEVEL control is at a
setting outside
the amplitude
range of the trigger signal. This type of
free-running
display
can be useful when it is desired to
measure only the maximum
peak-to-peak amplitude of a
signal
without
observing the
waveshape (such as in band
width
measurements).
When the display is of
a
much
greater
amplitude than
can be
displayed on the CRT, the
sweep
will be triggered in all
positions of
the LEVEL
control and will
not
free-run.
NORM.
When the
NORM
pushbutton is
pressed, a
triggered display
is presented with the correct setting of the
LEVEL
control and SLOPE switch whenever an
adequate
trigger signal is applied.
The
TRIG'D light indicates when
the
display is triggered.
The NORM trigger
mode must be used to produce
triggered
displays with trigger
repetition rates below about
30
hertz. When
the LEVEL control is at a setting outside
the amplitude range of
the trigger signal, when the trigger
repetition
rate is outside the frequency
range selected by
the
COUPLING switch,
or
when the trigger signal is
inadequate,
there is
no trace (TRIG'D light is off).
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