Fluke 9640A Series, Instruction Manual

Page: 205 / 324

Calibration
Performance Test
5
5-15
Note
It may be necessary to readjust the measuring receiver’s settings from those
automatically configured in the modulation measurement mode. In
particular, to ensure the demodulation bandwidth and measurement time
settings are adequate to accommodate the modulated signal RF spectrum
and to capture at least five cycles of the modulation waveform.
3. On the UUT press the
MOD
key, followed by the
Modulation Select
softkey and
ensure amplitude modulation (AM) is selected. Set the UUT as follows:
Frequency 30 MHz
Level +10 dBm
Mod Rate 1kHz (Sine)
AM Depth 50%
Output
OPER
Modulation ON
4. Use the measuring receiver autotune feature to tune to the input signal and measure
the AM rate. Verify that the measured rate is within the tolerance listed in Table 5-7.
5. Set the UUT modulation rate to 220kHz and repeat step 4.
Table 5-7. AM Rate Test
Frequency Modulation
Rate
Depth Tolerance
1 kHz 50 % 0.999 90 – 1.000 10 kHz 30 MHz
220 kHz 50 % 219.990 – 220.010 kHz
6. Set the UUT as follows:
Frequency 125 MHz
Level +14 dBm
Mod Rate 1kHz (Sine)
AM Depth 80%
Output
OPER
Modulation ON
7. Use the measuring receiver autotune feature to tune to the input signal and measure
the AM depth. Verify that the measured depth is within the tolerance listed in Table
5-8.