Comtech EF Data Vipersat CDM-570 User Manual page 133

Description
menu). If these home state parameters have not been entered, DPC will not be
able to function and will disable itself, resulting in an error message that is
displayed in the CLI.
Under most circumstances, the system will be running at the Calibrated Data
Rate, at the Calibrated Nominal Power level. When the VMS sends a switch
command to the CDM, the modem will go to a different data rate, and will
calculate a nominal power level for the transmitter. Communication is estab-
lished, data starts to flow, and the modulator begins receiving DPC packets
from the demodulator and adjusting its transmit power level accordingly. When
changing its power, the CDM will calculate a scaled maximum power based on
its current data rate and certain other values in the home state. This calculated
maximum is what insures that the modulator is not transmitting with more
power than is necessary, thus preventing problems such as over-saturation.
DPC parameters can be set from either the VMS or the CLI. After enabling the
DPC feature for a unit, a reset is not necessary. However, when enabling DPC
in a Remote expansion unit that is currently being used for a mesh connection,
that connection must terminate (e.g., revert the Remote) and a new switch occur
before the DPC function will become active. After switching, once the first
DPC packet from the demodulator(s) is received, the DPC state will begin track-
ing and start adjusting the modulator power output.
A p p e n d i x D y n a m i c P o w e r C o n t r o l
C - C-7