Fluke 9640A Series, Instruction Manual

Page: 206 / 324

9640A
Instruction Manual
5-16
8. Repeat step 7 for the remaining AM depth test points listed in Table 5-8.
Table 5-8. AM Depth Test
Frequency Modulation
Rate
Depth Tolerance
1 kHz 80 % 77.5 – 82.5 % 125 MHz
100 kHz 80 % 77.5 – 82.5 %
1 kHz 80 % 77.5 – 82.5 % 1 GHz
100 kHz 80 % 77.5 – 82.5 %
9. On the UUT press the
Modulation Select
softkey and select frequency modulation
(FM). Set the UUT as follows:
Frequency 125 MHz
Level +13 dBm
Mod Rate 1 kHz (Sine)
FM Deviation 300 kHz
Output
OPER
Modulation OFF
10. Use the measuring receiver autotune feature to tune to the input signal and when
tuning is complete set the UUT to
Modulation ON
.
11. Measure the FM rate. Verify that the measured rate is within the tolerance listed in
Table 5-9.
Note
For accurate FM measurements the measuring receiver’s setting
demodulation bandwidth setting must be > 3 x {rate + deviation}. In order
to meet this requirement at higher rate and deviation frequencies the
demodulation bandwidth setting must be increased from the default
automatically configured in the modulation measurement mode.
Table 5-9. FM Rate Test
Frequency Modulation
Rate
Deviation Tolerance
125 MHz 1 kHz 300 kHz 9,999 90 – 1.000 10 kHz
1 GHz 300 kHz 1 MHz 299.990 – 300.010 kHz