Promax PROWATCH Neo + Manual page 171

5.19 Shoulders Attenuation
5.19.1 Description
The Shoulders Attenuation function measures interferences in adjacent channels
that look like shoulders.
Broadcast signals such as DVB-T, DVB-T2, ISDB-T or ATSC are constructed to
follow strict RF requirements mostly aimed to ensure they occupy the bandwidth
they have been assigned and they do not interfere with any other adjacent
channels. In particular the shape of the signal spectrum must be within the limits
of certain given masks specified in the different corresponding standards, i.e.
ETR290 recommendations for DVB-T. The specific masks depend on the type of
signal and standard.
Due mainly to nonlinearities in the power amplifiers the output RF signal
contains unwanted band limit and out of band components, the shape of which
has given rise to the term "shoulder", that tend to compromise the compliance
with the mask limits.
5.19.2 Operation
Shoulders attenuation tool is available for digital terrestrial signals.
1 Shoulder attenuation should be measured at the output of the power
amplifier right before sending the signal to the antenna through the net of
passive devices. Because of the power level typically available at that point
it is mandatory to use external power attenuators so that the level can be
adapted to the máximum accepted by the analyzer.
2 Connect the signal to be measured to the RF input.
3 Tune a digital channel in terrestrial band.
4 Press the
5 Select the Shoulders Attenuation option.
6 The Shoulders Attenuation screen shows up.
March 2025
Shoulders attenuation
Tools key.
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Chapter 5: TOOLS