R.V.R. Elettronica TEX20-NV, Техническое руководство

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TEX20-NV Technical and Maintenance Manual
R.V.R. Elettronica S.r.l. (Bo) Pag. 45
8) Verify on the meter that is present a reading of 75KHz, if not,
adjust R33 trimmer.
9) Connect an audio generator to the MPX input.
10) Inject a 400Hz, 0dBm (775mVrms, 2.2Vpp) tone into the MPX input.
11) Configure the FAM to measure deviation with the 30Hz-200KHz/FM/P+
filters and check that it is 75KHz.
If not, adjust trimmer R35 accordingly.
Then, remove the pilot tone with the switch, configure the FAM to
measure distortion and adjust trimmer R34 to minimize distortion.
12) Check that the deviation remains constant right across the band and,
if not, adjust trimmer R36 on the Main Card, accordingly.
13) Repeat steps 11) and 12) to obtain the best adjustment on all
frequency range.
N.B. The audio generator used in these tests must have a distortion
figure better than 0.001%.
Perform this test at the operating frequency of the exciter.
5.2 RF POWER AMPLIFIER MODULE CALIBRATION
After having replaced the amplifier, carry out the following procedure
(see SETUP8):
1) Connect a bypass wattmeter between the RF output and a 50Ohm, 20W
dummy load.
2) Rotate the PWR ADJ trimmer anti-clockwise (min. output power),
switch on the exciter and set the frequency to 98.00 MHz. Wait for
the PLL to lock and the power output to be enabled.
3) Rotate the PWR ADJ trimmer clockwise (6 Fig.1A and 4 Fig.1B) to
obtain maximum power output.
4) Take a reading of the output power. If this is not 20W, adjust
trimmer R1 on the Power Supply card accordingly.
SETUP 8