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GV5/GV3.5 OPERATIONS & MAINTENANCE MANUAL OPERATING THE TRANSMITTER
VERSION 0.2 2014-07-23 PAGE 3.2.79
Figure 3.2.57: IBOC Settings editing screens
For FM+HD and HD modes, use the up and down buttons to
select a value between -20 and -10 dB for the IBOC injection
level of the lower sideband of digital carriers. This value
determines the relationship between the digital carriers power
and the analog carrier power. Example: -20 dBc indicates that
the total RMS power of the digital carriers will be 1% of the total
RMS power of the analog carrier. -10 dB indicates that the total
RMS power of the digital carriers will be 10% of the total RMS
power of the analog carrier.
NOTE: The preferred option to maximize IBOC performance is by
using the HD Optimizer feature (see
Optimizing HD Parame-
ters, on page 3.2.118
) . In this case, leave PA Volts setting at
its default
value (53.0 V).
For FM+HD, HD and DRM+ modes, use the up and down buttons
to enter a value between 30.0 V and 53.0 V. This value sets the
drain voltage applied to the PAs in the RF power modules, from
their associated power supplies. This value affects IBOC/DRM+
performance. Larger values result in an improved spectrum, but
decreased efficiency. Conversely, smaller values result in improved
efficiency, but degrade the spectrum. Typical values are between
35 V and 50 V, and depend on many variables such as power level,
frequency and injection level.
For FM+HD mode only. Use the up and down buttons to toggle
between Efficiency Priority (default setting) and MAX MER Priority.
Selecting Efficiency Priority instructs the PowerBoost function to
make efficiency and power capability the priority when reducing
the peak-to-average power ratio, while ensuring that the MER
(modulation error ratio) of the transmitted HD signal meets trans-
mission requirements.
Selecting MAX MER Priority instructs the PowerBoost function to
make maximum MER the priority. Transmitter efficiency and power
capability will be reduced as a result.
PowerBoost is only available in transmitters with the appropriate
exciter configuration.
For FM+HD and HD modes, use the up and down buttons to
select a value between -20 and -10 dB for the IBOC injection level
of the upper sideband of digital carriers. This value determines
the relationship between the digital carriers power and the
analog carrier power. Example: -20 dBc indicates that the total
RMS power of the digital carriers will be 1% of the total RMS
power of the analog carrier. -10 dB indicates that the total RMS
power of the digital carriers will be 10% of the total RMS power
of the analog carrier.