Motorola R-2400 Operator's Manual page 33

4.4.2.I
PWR MON WITH
SPECTRUM ANALYZER
(R-2400
only)
For high
power signal monitoring (.5
to
125
watts)
l.
Connect the radio under
test
antenna out to the "RF
InlOut"
connector on the
service
monitor.
2.
Set
the function switch to "Anlzr
Pwr Mon".
3.
Adjust the Vertical and Horizontal position controls
if
necessary (see
3
.6.
8).
4.
Enter the RF frequency from the keyboard.
5.
Move the
right
cursor
to
"PWR".
6.
Adjust the RF
Step attenuator
for
maximum attenu-
ation (70
dB)
7
.
Key the radio under test and adjust the RF
step at-
tenuator
for
the
desired
viewing
level.
8.
Read the
output power on the LCD display.
4.4.3 TRANSMITTER DISTORTION
MEASURE-
MENTS
IN THE PWR MON FUNCTION
The distortion meter display can be viewed
in
either
Generate
or
Monitor function. The distortion
meter
measures
the quality of the audio.
1.
Connect the RF IN/OLJT to the radio antenna jack
and connect the modulation output to the radio
mic
input.
Connect
the DEMOD output to the
multi-
purpose
input BNC connector. This
allows the unit to
be used
as
a test
receiver.
2.
Enter the RF Frequency
trtrtrtrtrtrtrtrtr
3.
Set
the
function switch ro Pwr Mon and
tr
ro Dist.
To display modulation waveforms of the transmitter
turn the
oscilloscope source switch
to "MOD."
Adjust the I kHz tone
level
for proper deviation. (out
of clipping) Disable PL if
resident in the rransmitter.
Read
transmitter audio distortion in
o/o
on the digital
readout. Note that transmitter power and frequency
error can also be displayed on the right LCD.
FIGURE
4.s-TEST
SET-UP FOR
TRANSMITTER DISTORTION MEASUREMENT
4.
5.
6.
4.4.4 MEASUREMENT OF TRANSMITTED .(PL"
TONE
With the internal PL
frequency counter
it
is
possible to
measure
the PL tone
of
a
transmitter. The
function
switch
can be moved to
either monitor function position.
l.
Select
the PL Count mode located in the modulation
section using
the
tr cursor.
2.
Select SENS
MON
(sensitive monitor) for off-the-air
monitoring.
3.
Enter the frequency from the keyboard.
trtrtrtrtrtrtrtr8
4.
Key
the
transmitter under
test and read
PL frequency
in the upper portion of the right LCD.
NOTE: The
PL
frequency counter measures frequency
inputs in the
range
of
60
Hz to
270
Hz. The output of
the
counter
is
displayed on the
right LCD with resolution of
.l
Hz. In
cases
of low PL tone deviation,
the value
of
the
tenths digit may fluctuate periodically.
It
may
be
neces-
sary
to
average
the displayed
values over
time to deter-
mine the PL frequency
within
.5 percent
accuracy.
FIGURE
4.6-TEST
SET-UP FOR
PL COUNTER MEASUREMENT
4.4.5 SIMULTANEOUS OSCILLOSCOPE/DVM
OP.
ERATION
The
use
of
separate
CRT
and
LCD
displays makes
it
possible
to
view signal
waveforms
on the
oscilloscope
and
simultaneously view
the measured digital
and analog
values
of the waveform on the left LCD. To
measure
an
AC waveform (RMS value)
and display the waveform
on
the oscilloscope CRT:
1. Connect the multipurpose input test probe to
the
circuit to be
measured.
2.
Move
the
left
tr
cursor to
DVM
and select
AC volts
for
display.
3.
Select
the EXT AC
position
on the
oscilloscope
"SOURCE"
switch.
4.
Select the proper
Volt
per division
scale and center
the
trace.
\-/
\rtl
[lwE
Vert/SINAD
DEMOD
MOD
Dist/DVM OUT
OUT
TRANSMITTER
4-4
\-/