Hum Modulation - Deviser S7200 User Manual

Part II: Settings and Measurements
4-3

HUM Modulation

From the Channel Measurement mode, tap HUM to start the HUM modulation function.
Hum is an interference type that generates harmonics following AC frequencies. This phenomenon creates
a visible distortion in television signals. With the Hum Modulation function, the S7200 measures the effects of
this interference on analog and digital channels. The analog measurement screen is shown below.
4-3.1 Settings
Channel: The channel to measure. Select any active analog or digital channel in the active
channel plan.
Frequency: Input range 4-1220 MHz.
Button Operation
[50Hz] / [60Hz]: Toggles the power frequency between 50Hz and 60Hz (depending on region).
Hold: Pauses the measurement. Press again to resume.
Test Results
Video Level: Displays the level of the current analog video signal.
Hum Modulation: Degree of hum modulation interference, as measured on the analog video carrier.
Freq Component: Displays the percentage of each frequency component.
Low-frequency interference and interference harmonic will cause disruptions in an analog TV signal.
On the S7200, the highest measurable fourth harmonic is:
 50Hz: 50Hz, 100Hz, 150Hz and 200Hz
 60Hz: 60Hz, 120Hz, 180Hz and 240Hz
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