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Calculation of DL_TAR and DL_GAIN
DL_TAR and DL_GAIN are the key parameters for commissioning the downlink that must be calculated and
set up in the BDA.
• DL_TAR: Downlink Target Channel Power; Sets the MAX DL Channel Power for a channel filter.
The DL Channel AGC circuits will prevent the Channel Filter from exceeding this power level.
• DL_GAIN: Downlink Channel Gain; Sets the MAX DL Gain for each channel filter. The device will
use the MAX DL Gain for each channel. If a Channel Filter’s DL input power is high such that the
MAX DL Gain is not needed to achieve full DL_TAR, the DL Channel AGC circuits will automatically
reduce the DL Gain accordingly to reach DL_TAR.
DL_TAR is calculated using the DL Composite Power and the total channel count per band. The BDA will
derate from composite power and evenly share total power across all the channels in a band according to the
formula below.
DL_TAR = DL Composite Power – 10Log(# of channels)
Example:
DL Composite Power = 33dBm
# of Channels = 8
DL_TAR = 33 – 10Log(8) = 33 – 9 = 24dbm
Table 18: Commissioning Tool - DL_TAR Channel Power Derating
DL_GAIN is calculated using the DL Control Channel Input Power and the DL_TAR. The BDA can measure
the DL Input Power using the onboard test, or the user can enter a manual measurement. DL_GAIN is then
calculated using the formula below.
DL_GAIN = DL_TAR – DL IN (Control Channel Input)
Example:
DL_TAR = 20dBm
DL_IN = -65dBm
DL_GAIN = 20 – (-65) = 85dB
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