Digital Storage Displays - Tektronix 2221 Operator's Manual

Basic Applications— 2221 Operators
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NOTE
5. Adjust the TRIGGER LEVEL control for a stable ,
triggered display .
6. Set the SEC/ DIV switch for the desired number of
cycles of displayed signal. Then adjust the FOCUS control
for the best - defined display.
The display obtained when sinusoidal signals are
applied to the X- and Y -axis is called a Lissajous
Figure. This display is commonly used to compare
the frequency and phase relationship of the two
input signals. The frequency relationship of the two
input signals determines the pattern seen . The pat
tern will be stable only if a common divisor exists
between the two frequencies.
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Magnified Sweep Display
1. Preset the instrument controls and obtain a baseline
display.
6. Set the X-Y button to the out position and discon
nect the input signals from the vertical input connectors .
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2. Adjust the Horizontal POSITION control to move the
area to be magnified to within the center crt graticule divi
sion ( 0.5 division on each side of the center vertical grati
cule line ). Change the SEC/ DIV switch setting as required .
Single Sweep Display
1. Preset the instrument controls and obtain a baseline
display .
3. Pull out the SEC/DIV Variable knob and adjust the
Horizontal POSITION control for precise positioning of the
magnified display .
2. For random signals , set the TRIGGER LEVEL con
trol to trigger the sweep on a signal that is approximately
the same amplitude as the random signal .
X - Y Display
1. Preset the instrument controls and obtain a base
line display.
3. Press in the SGL SWP
RESET
button
for a
moment. The next trigger pulse will initiate the sweep , and
a single trace will be displayed. If no trigger signal is
present, the READY indicator LED should illuminate to
indicate that the SWEEP Generator circuit is set to initiate
a sweep when a trigger signal is received.
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2. Rotate the INTENSITY control fully counterclock
wise and disconnect the CH 1 input signal.
3. Use two coaxial cables or probes of equal delay and
apply the vertical signal (Y-axis) to the CH 2 OR Y input
connector and the horizontal signal ( X -axis ) to the CH 1
OR X input connector.
4. When the single sweep has been triggered and the
sweep is completed , the sweep logic circuitry is locked
out. Another sweep cannot be generated until the SGL
SWP RESET button is pressed in to set the Sweep Gen
erator to the READY condition .
4. Set the VERTICAL MODE switch to X-Y ( button in ).
DIGITAL STORAGE DISPLAYS
5. Advance the INTENSITY control until the display is
visible. If the display is not visible with the INTENSITY
control at midrange, press and hold in the BEAM FIND
button while adjusting the Channel 1
and Channel 2
VOLTS /DIV switches until the display is reduced in size,
both vertically and horizontally . Center the compressed
display with the POSITION controls (Channel 2 POSITION
control for vertical movement; Horizontal POSITION con
trol for horizontal movement). Release the BEAM FIND
button .
Adjust the FOCUS control for a well- defined
display.
The following procedures explain how to set up and use
the digital storage capabilities of the instrument . The
front-panel control selections set the conditions under
which a waveform is acquired for display. Display ampli
tude is controlled
by the
VOLTS /DIV switches . The
storage time base is controlled by the SEC/ DIV switch ,
and the CURSORS controls. The SEC/ DIV switch and the
TRIGGER Mode switch will acquire and display waveforms
using parameters of Table 3-2 .
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