PERFORMANCE TESTS
d. Set the distortion analyzer to measure distortion at 1 kHz.
e. Verify that the modulation analyzer reading is between 19 and 21 kHz, and that
the THD is less than 2%. Repeat at deviations of 5 and 10 kHz. Verify that the
modulation analyzer reading is within ± 5% of programmed value. (See the
following NOTE).
f. Program the UUT to deviation of 50, 100, and 200 kHz.
g. Verify that the modulation analyzer reading is the deviation programmed ± 5%
and that the distortion is less than 5%.
h. Repeat steps d through g with the modulation rate set to 100 Hz. Verify
distortion only.
NOTE
Change the modulation analyzer bandwidth and distortion analyzer
frequency appropriately for modulation frequency for steps h through p.
i. Repeat steps d through g with modulation rate set to 50 kHz. Verify distortion
only.
j. Program UUT to 40-MHz frequency, 25-kHz deviation and 1-kHz INT
modulation frequency.
k. Verify that the Modulation Analyzer reading is between 23.75 and 26.25 and
that the distortion is less than 5%.
1. Program the UUT to deviation of 50, 100, 200, and 250 kHz.
m. Verify that the modulation analyzer readings correspond to that programmed
± 5% and that the distortion is less than 5%.
n. Repeat steps j through m with the modulation rate set to 100 Hz. Verify
distortion only.
o. Repeat steps j through m with the modulation rate set to 50 kHz. Verify
distortion only.
p. Set the modulation rate to 100 kHz with 250 kHz deviation. Verify that
measured deviation is greater than 177 kHz (3 dB bandwidth).
NOTE
It may be necessary to compensate for residual noise effects using the
procedure presented in the manual provided with the Modulation
Analyzer.
8. øM Accuracy Test
a. Connect the LFSSG output to the UUT MOD INPUT connector and the
DVM (use a BNC T connector).
4-21
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