Operating Instructions—Type 422 AC-DC
Second Tenth
vertical vertical
line line
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Fig. 2-12. Area of graticule used for accurate time measurements.
end of the timing 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 of 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 of 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, first move the portion of
the display to be expanded to the center of the graticule.
Then pull the X I0 MAG switch. The light located below
the X I0 MAG switch is on whenever the magnifier is on.
When the X I0 MAG switch is pulled out, the sweep rate
is determined by dividing the TIME/DIV switch setting by
10. For example, if the TIME/DIV switch is set to .5 |J£, the
magnified sweep rate is 0.05 microsecond/division. The
magnified sweep rate must be used for all time measure
ments when the X I0 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 for a range of about 0.5 division for
normal sweep, or five divisions for 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 of the trace. To use this con
trol effectively for precise positioning, first 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 time (internal
sweep). The EXT HORIZ position of the TIME/DIV switch
provides a means for applying an external signal to the
horizontal amplifier for this type of display.
Connect the external horizontal signal to the HORIZ IN
connector (TRIG IN). With the HORIZ ATTEN control
TRIGGERING LEVEL) fully clockwise and the X10 MAG
switch pushed in, the horizontal deflection factor is about
10 volts/division. Deflection factor with the X I0 MAG
switch pulled out is about one volt/division. The HORIZ
ATTEN control provides at least 10:1 variable attenuation
within the above ranges. The X and Y channels of this
instrument areonot time matched and some inherent phase
shift is apparent. Take this inherent phase shift 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 BLANKING
connector. External blanking signals are direct-coupled to
the blanking deflection plates. A two-volt positive signal
connected to the EXT BLANKING connector on the front
panel will completely blank the display at any INTENSITY
control setting. For external blanking, the CRT display
cannot be satisfactorily intensity-modulated, but is either
turned on or off. Deflection blanking systems (as used in
the Type 422) do not provide a “ gray scale".
2-20
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