BASIC
FM
TRANSMITTER
TESTS
POWER, FREQUENCY,
AND
DEVIA
nON
4. Adjust the attenuator as in step A-3 above, to produce an adequate signal level to the Analyzer's Monitor receiver.
5. Adjust the transmitter and follow the same procedure outlined
in
steps A-5 through A-7 above, to measure fre-
quency and deviation.
6.
This same method may be used to verify frequency and deviation
of
a remotely located transmitter by reducing the
attenuator setting to fully realize the 1.5uV for lOdb SINAD sensitivity
of
the Analyzer's "of-the-air" monitor
function.
To
insure sufficient measurement accuracy however, make sure the Monitor receiver is fully quieted as
in step A-3 above.
C. "In-Line" Power Measurements
1.
Referring
to
figure
4-8,
connect
the
RTL·4055B
in·line
wattmeter
adapter
with
the
appropriate
~T-l200
series
ele-
ment in the
50
ohm antenna line with the arrow pointing towards the antenna. Plug the adapter's cable into the
Analyzer's Ext Wattmeter jack. Refer to table 3-12 in this Manual for further description
of
elements.
2.
Set DISPLAY to Ext Wattmeter, FUNCTION switch to Monitor FM,
and
the attenuator to
-30
dB. In this step,
FUNCTION switch and attenuator do not function but should be set in case RF power
is
inadvertently applied to
the RF
In/Out
connector.
3.
Use the keypad to select the scale that corresponds to the ST-1200 element
in
use.
4.
Key
the transmitter. Read forward and reflected power
on
the display.
4-16
'-----....-
'-../
"--'"
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