Tektronix 422, Instruction Manual

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Operating Instructions—Type 422 AC-DC
Second Tenth
vertical vertical
line line
t i l l i i i i i i i i
I N I
"1 I Tf .ITT V Mi l
I N I
lim e
eas u re m e
a r e a
Fig. 2-12. Area o f graticule used for accurate time measurements.
end of the tim ing area falls between the second and tenth
vertical lines.
Sweep Magnification
The sweep magnifier expands the sweep ten times. The
center division of the unmagnified display is the portion
visible on the screen in magnified form (see Fig. 2-13).
Equivalent length o f the magnified sweep is more than 100
divisions; any 10-division portion can be viewed by adjust­
ing the horizontal POSITION control to bring the desired
portion onto the viewing area. The dual-range feature o f the
horizontal POSITION control (see Horizontal Position Con­
trol discussion which follows) is particularly useful when
the magnifier is on.
Unmagnified waveform
Fig. 2-13. Operation of the sweep magnifier.
To use the magnified sweep, firs t move the portion of
the display to be expanded to the center of the graticule.
Then pull the X I 0 MAG switch. The light located below
the X I 0 MAG switch is on whenever the magnifier is on.
When the X I 0 MAG switch is pulled out, the sweep rate
is determined by dividing the T IM E /D IV switch setting by
10. For example, if the T IM E /D IV switch is set to .5 |J£, the
magnified sweep rate is 0.05 microsecond/division. The
magnified sweep rate must be used fo r all tim e measure­
ments when the X I 0 MAG switch is pulled out. The magni­
fied sweep rate is calibrated when the UNCAL light is off.
Horizontal Position Control
The dual-range horizontal POSITION control used in the
Type 422 provides a combination of coarse and fine adjust­
ments in a single control. When this control is rotated, fine
positioning is provided fo r a range o f about 0.5 division fo r
normal sweep, or five divisions fo r magnified operation and
the trace can be positioned precisely. Then, after the fine
range is exceeded, the coarse adjustment comes into effect
to provide rapid positioning o f the trace. To use this con­
trol effectively fo r precise positioning, firs t turn the control
to move the trace slightly beyond the desired position
(coarse range). Then reverse the direction of rotation to use
the fine range to establish the precise trace position desired.
External Horizontal Input
In some applications it is desirable to display one signal
versus another signal rather than against tim e (internal
sweep). The EXT HORIZ position o f the T IM E /D IV switch
provides a means fo r applying an external signal to the
horizontal am plifier fo r this type o f display.
Connect the external horizontal signal to the HORIZ IN
connector (TRIG IN). With the HORIZ ATTEN control
TRIGGERING LEVEL) fu lly clockwise and the X10 MAG
switch pushed in, the horizontal deflection factor is about
10 volts/division. Deflection factor w ith the X I 0 MAG
switch pulled out is about one volt/division. The HORIZ
ATTEN control provides at least 10:1 variable attenuation
w ithin the above ranges. The X and Y channels of this
instrument areonot tim e matched and some inherent phase
shift is apparent. Take this inherent phase sh ift into
account
when making measurements. For aid in
interpreting lissajous displays, refer to the reference books
listed under Applications.
External Blanking
The CRT display of the Type 422 can be externally
blanked by a signal connected to the EXT BLAN KING
connector. External blanking signals are direct-coupled to
the blanking deflection plates. A tw o-volt positive signal
connected to the EXT BLANKING connector on the fro n t
panel w ill completely blank the display at any INTENSITY
control setting. For external blanking, the CRT display
cannot be satisfactorily intensity-modulated, b ut is either
turned on or o ff. Deflection blanking systems (as used in
the Type 422) do not provide a “ gray scale".
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