Tektronix 543B, Instruction Manual

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Operating Instructions — Type 543B/RM543B
Single-Sweep Operation
In applications where the displayed signal is not repeti-
tive or varies in amplitude, shape, or time, a photograph
of a conventional repetitive display may produce a jumbled
presentation. To avoid this, use the single-sweep feature to
photograph this type of display. To use single sweep, first
make sure the trigger circuit will trigger on the event you
wish to display. Do this in the conventional manner. Then,
press the SINGLE SWEEP switch to RESET and release.
When this is completed, the next trigger pulse will actuate
the sweep and the Type 543B will display the event on
a single trace. The READY lamp, near the SINGLE SWEEP
swit ch, first lights when the sweep is ready to accept a
trigger and then goes out after triggering has taken place.
To ready the circuit for another single display, press the
SINGLE SWEEP switch to RESET and release. In single­
sweep operation, make sure the TRIGGER MODE switch is
not set to AUTO.
NONTRIGGERED SWEEP
Ordinarily, the displayed signal is also used to trigger
t he oscilloscope sweep. In some situations, it may be de­
sirable to reverse this situation. The sweep-related output
pulses, available from the front panel of the Type 543B, can
be used as a triggering signal for an external device. The
output signal of the external device can then produce a
stable display while the oscilloscope sweep free runs.
To demonstrate one method of performing this operation,
oroceed as follows;
Set the controls and switches as follows.
TRIGGER SLOPE
TRIGGERING MODE
STABILITY
TIME/CM
+EXT
AC
Fully clockwise
1 mSEC
Connect a lead from the SAWTOOTH OUT connector
to the vertical input. The display should consist of a sloping
line.
The oscilloscope display is the sawtooth pulse that is
available during each sweep. In a practical application,
the pulse would not be applied to the vertical input but
instead to some external device to be tested. The pulse
would then serve as the trigger pulse or input signal from
rhe external device, and the output of the device would
provide a stable display on the oscilloscope, as though the
oscilloscope were triggered in the normal manner.
The —GATE OUT connector output signal of the Type
543B can be used as a variable repetition-rate pulse gen­
erator. To use the Type 543B in this manner, proceed as
follows;
Set the controls and switches as follows:
TRIGGER SLOPE
TRIGGERING MODE
STABILITY
TIME/CM
+EXT
AC
Fully clockwise
As desired
Monitor the signal available at the +GATE OUT con­
nector on another oscilloscope and establish the desired
pulse repetition rate by setting the TIME/CM and VARIABLE
controls.
Light Filter
The light filter provided with the Type 543B minimizes
undesirable reflections when viewing the display under high
ambient light conditions. The filter may be left on when
taking waveform photographs unless a high writing rate is
required.
If the light filter is removed, the crt protector plate should
be installed to prevent scratches to the crt face plate.
EXTERNAL HORIZONTAL DEFLECTION
For special applications, horizontal deflection can be
produced with an externally derived signal. Thus, the
oscilloscope system can be used to plot one function against
another (e.g. Lissajous figures). However, the system is not
intended for precise phase-angle measurements.
To use an external signal for horizontal deflection, con­
nect the signal to the EXTERNAL HORIZ IN connector. Set
the HORIZONTAL DISPLAY switch to EXT and the EXTERNAL
HORIZONTAL VOLTS/CM control to 0.1, 1 or 10. The
signal is dc coupled to the deflection amplifier.
The time-base generator still controls rhe unblanking of the
crt display when the HORIZONTAL DISPLAY switch is set
to EXT. To unblank the crt at a normal setting of the
INTENSITY control, it will be necessary to have the SINGLE
SWEEP switch set to NORMAL SWEEP and the time-base
triggering controls set for a free-running sweep. If it is
undesirable to have the time-base generator running, then
the INTENSITY control will have to be turned up until the
beam is visible.
DUAL-TRACE CHOPPED BLANKING
A
dual-trace plug-in unit provides two separate traces
on the crt and thus permits two functions to be displayed
simultaneously. Detailed instructions for operating the dual­
trace p'ug-in unit in conjunction with the Type 543B Oscillo­
scope are contained in the plug-in unit instruction manual.
When the dual-trace plug-in unit is operated in the
chopped mode to obtain a dual-trace presentation, switch­
ing transients will be displayed on the crt. These switching
transients can be reduced by placing the CRT CATHODE
SELECTOR switch on the rear of the instrument in the
CHOPPED BLANKING position.
INTENSITY MODULATION
The Type 543B crt display can be intensity modulated by
an external signal to display additional information. This
is done by disconnecting the grounding bar from the EX­
TERNAL CRT CATHODE connector at the rear of the instru­
ment and connecting the external signal to this terminal.
The CRT CATHODE SELECTOR switch must be in the EX­
TERNAL CRT CATHODE position.
Very accurate time measurements can be made by intensity
modulating the beam with time markers and measuring
directly from the time markers on the crt. A positive signal
of approximately 20 volts is required to cut off the beam
from normal intensity. The low-frequency cutoff point for
Z-axis modulation is 600 cps.
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