Nautel GV5, Operation & Maintenance Manual, Page: 81 / 251

GV5/GV3.5 OPERATIONS & MAINTENANCE MANUAL OPERATING THE TRANSMITTER
PAGE 3.2.64 VERSION 0.2 2014-07-23
Mode - Additional Calibration Settings:
 IBOC Injection (Lower): for FM+HD and HD modes, enter value, in dB, 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 dB indicates that the total RMS power of the digital carriers will be 1/100 of the
total RMS power of the analog carrier. -10 dB indicates that the total RMS power of the digital
carriers will be 1/10 of the total RMS power of the analog carrier.
 IBOC Injection (Upper): for FM+HD and HD modes, enter value, in dB, 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 dB indicates that the total RMS power of the digital carriers will be 1/100 of the
total RMS power of the analog carrier. -10 dB indicates that the total RMS power of the digital
carriers will be 1/10 of the total RMS power of the analog carrier.
NOTE
:
The actual digital sideband power is 3 dB less than that indicated in the upper or lower IBOC
Injection fields; Example: if -20 dBc is entered in the upper and lower IBOC Injection fields, the upper
and lower digital sideband power levels are actually -23 dBc; this way, when added, the resultant total
digital power level is -20 dBc.
For symmetrical sideband transmission: if -14 dBc IBOC Injection level is desired (total digital power of
upper + lower sidebands is 4% of analog carrier power), set the upper and lower IBOC Injection levels
to -14 dBc.
For asymmetrical sideband transmission, account for the fact that the actual sideband power level is
3 dB less than that shown. For example, if the upper digital sideband IBOC Injection level is entered as
-14 dBc, the actual power level will be -17 dBc. This is equally true for the lower digital sideband.
 HD PA Volts: for FM+HD, HD and DRM+ modes, enter value, in volts, between 30.0 V and
53.0 V (default is 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. You can also use the HD optimizer feature to maximize your transmitter’s performance
(see
Spectrum/Efficiency Optimizer, on page 3.2.108 or Optimizing HD Parameters, on page
3.2.118 ).
 HD Power Boost: for FM+HD mode only. Enable this setting to engage Nautel’s digital
PowerBoost process, an advanced peak-to-average power ratio reduction that increases
hybrid-mode transmitter efficiency and power capability. When enabled, selection options are
Priority: Efficiency and Priority: MER.