R&S FSL Cable TV Measurements (Option K20)
1300.2519.12 2.55 E-11
Hum measurement
This measurement determines whether the signal comprises hum, a not–wanted amplitude modulation
of the analog TV signal, mostly due to defective amplifiers. For the Hum measurement, the AM
modulated frequency must be below 1 kHz and is typically equal to the power line frequency times one
or two, e.g. 50 Hz, 60 Hz, 100 Hz, 120 Hz.
Test setup:
Refer to the section Analog TV test setup.
Procedure:
1. Press the MEAS key.
2. Press the Analog TV softkey.
3. Press the More softkey.
4. Press the Hum softkey.
5. If you want to adjust the range of the y–axis, press the Auto Range softkey.
6. To change the limits, press the Edit Table softkey.
7. To adjust the input attenuator, press the Adjust Attenuation softkey.
8. Press the FREQ key.
9. Enter 210.25 MHz for the vision carrier frequency of the input signal.
10. Press the RUN key.
In case you use a TV test transmitter or your CATV network is in good condition, you will see a
rather flat line, since there will be little hum.
Fig. 2-37 Hum measurement
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