Motorola R-2400 Operator's Manual page 40

C.
4. Adjust the
attenuator as
in
step
A-3
above, to
produce an adequate signal level
to
the
service
monitor's
receiver.
5. Adjust
the transmitter and follow the
same
pro-
cedure
outlined in
steps
A-5 through A-7
above,
to
measure frequency and deviation.
6. This
same method may be used
to
verify
fre-
quency and
deviation of
a
remotely
located trans-
mitter by reducing the attenuator setting to fully
realize
the
l.5uv
(10 dB SINAD) sensitivity of
the
service
monitor's "of-the -air" monitor func-
tion. To
insure sufficient
measurement accuracy
however, make
sure the
Monitor
receiver
is
fully
quieted
as
in
step
A-3
above.
Harmonic Power Measurement
(R-2400)
l.
Referring to
Figure 5.6, insert a fixed power
at-
tenuator
between the RF
output connector of
the
transmitter
and the
"Antenna"
port of
the
R-2400. The power rating of
this attenuator
must
be
at
least equal
to
the
rating of
the transmitter,
and
a
minimum of
30
dB attenuation. The input
power to
the antenna
port
must not
exceed 0.5
watt.
2.
Set
the "Function" switch
to
"Sens
Mon/Anlzr
On"
and enter the carrier frequetrcy,
as
before.
3.
observing the CAUTION above, with
a fixed at-
tenuator
in
series, key the transmitter and
set
the
step
attenuator
for
a
peak indication on
the
spec-
trum
analyzer between the REF and
- l0
dB
graticules.
Note the displayed level and the
step
position in dB. De-key the transmitter.
4.
Enter the frequency of
the harmonic
or
spurious
signal
of
interest. Key the
transmitter
and
observe
the level
of
the signal on the
spectrum
analyzer, adjust the
step attenuator
if
necessary,
should the
signal
be
too low to
observe.
confirm
that the signal
changes
l0
dB for a
l0
dB
change
in the
step
attenuator setting
(See
notes
on
page
5.2). Note the level of
the signal and the
step at-
tenuator setting, in dB. De-key the transmitter.
5.
Compute the level difference
between the carrier
and the spur/harmonic
as
follows:
A. Let
"REF":0
dB, and
step
position
is
a nega-
tive number.
B.
PC
-
displayed level
of
carrier-(step) ie.:
-3
dB-(-50
dB)
-
+
47 dB
C.
Pl
-
displayed level
of
spur-(step) ie.:
-22 dB-(-30
dB)-
+8
dB
D.
The relative difference
between the carrier
and
spur/harmonic
levels is
P
diff
:
PC-P
| :47
-8
:39
dB.
FIGURE
5.7
-TRANSMITTER AUDIO
FREQUENCY
RESPONSE
FIGURE
5.8
-TRANSMITTER AUDIO
DISTORTION
SETUP
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