Motorola R-2400 Operator's Manual page 23

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3.6.0
OSCIIOSCOPE/SPECTRUM
ANALYZER/MODUTATION
SCOPE SECTION
3.6.6
VERT
A
four position rotary
switch controls the vertical
dis-
play. Oscilloscope operation
uses
values marked to
the
right of
the switch indicating volts per division.
Values
marked to the left of the switch
are
used
when modula-
tion
is displayed
on the oscilloscope. The right
bezel
of
the
oscilloscope has a numerical
scale corresponding to
values
of
.25 kHz, 2.5 kHz
and 25 kHz per division.
This allows deviation
measurements
to
be made
even
when the service
monitor LCD display
is
not
selected
to
"DEV/VIAM"
and gives the technician the ability to
detect non-symmetric modulation. This switch
is
dis-
abled when the
R-2400
spectrum
analyzer is being
used.
3.6.7
VERT VERNIER
The vertical vernier potentiometer controls the vertical
inputs
to
the
oscilloscope.
The calibrated position
is
fully
clockwise.
NOTE: The vertical vernier potentiometer is also
func-
tional
when the R-2400 spectrum
analyzer mode
is
being
used.
It
is
important to
have
this control in the "Cal"
posi-
tion to
ensure
true l0dB/div vertical
accuracy.
FIGURE
3.s-CLOSEUP
OF SCOPE TRACE
3.6.8
POSITION
The stacked concentric potentiometers control the
ver-
tical and horizontal positions
of
the
scope trace.
For
R-2400 spectrum analyzer operation, these
con-
trols are
also used
to
center
the
observed
spectrum.
when
entering
the
spectrum analyzer mode, use
the
"Vert Position" control
(innermost control) to
set the
base
of
the noise
floor at
the bottom graticule.
The
Horiz Position control is
adjusted
by first
programm-
ing for an RF
frequency
of
000.0000
Mhz
(dc
reference),
then with the
dispersion control set for
lMhz/div,
use
the Horiz Position control
(outermost
potentiometer)
to
center the
observed spectrum display
horizontally around the center (sth) vertical graticule.
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FIGURE 3-4-CLOSEUP OF SCOPE CONTROLS
3.6.1 INTENSITY
The intensity control varies the brightness of the
scope
trace.
3.6.2
FOCUS
The focus control
varies the
sharpness of
the scope trace.
3.6.3
HORIZ
This
seven
position rotary switch
selects the
horizontal
sweep
rate or
the external hori zontal
sweep
input
when
the oscilloscope function is being
used. On the R-2400,
this
same
control is
used
to
select
the
dispersions
of l,
.1, and
.01
MHz/div
when the spectrum analyzer func-
tion
is selected
with the function switch. The
sweep rate
is
automatically fixed when
in
the spectrum
analyzer
mode.
3.6.4
HORIZ
VERNIER
This potentiometer controls the horizontal
sweep rate
when
the
oscilloscope functions
is
being used.
The
calibrated
position is the
fully
clockwise
position. This
control is disabled when the
R-2400 spectrum analyzer
function is being
used.
3.6.5
SOURCE
The source
control
is
a
three position rotary
switch
which
selects
the source for
the
scope
vertical input.
"MOD"
(modulation) will
display tho outgoing RF modulation
signal
or the
recovered modulation signal. The "EXT
AC"
(external AC)
position
selects
AC coupled external
input frorn the BNC connector. The "EXTDC"
(exter-
nal
DC) position
selects
the DC coupled external input
from the
same
BNC
connector.
3-8