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1.2.6 Over Drive (Excessive RF Ouput Level) and OPS
The unit's specified linear rated output power level, Plinear, can be found in the unit
datasheet. Although the unit may be capable, operating beyond its Plinear level is
discouraged. As the input drive level is increased, excessive distortion of the output sets in
which will result in degraded throughput and possible adjacent carrier interference.
Although the best protection against potentially degrading overdrive conditions is user
attention and vigilance to the input and output levels as mentioned above, Comtech has
implemented an overdrive protection software option
unit from damage and warn the user of gross overdrive conditions. However, it will be noted
that the OPS feature is only an aid in preventing and notifying the operator of overdriven
conditions, it does not guarantee protection of hardware or continuous unit operation in the
"usable power" region in extreme or persistent overdriven conditions.
The overdrive protection setting is on the amplifier webpage and the information is displayed
on the Status webpage. The settings are also available via serial commands (RS232/RS485).
With the overdrive protection mode activated, the operator can set a predetermined activation
level (P1dB rated to P1dB – 10) which will trigger the OPS to set either an Alarm or Fault if
the forward power is greater than the activation level. A Fault or Alarm will be determined by
the overdrive protection mask setting. If the mask setting is Fault, then the OPS will mute the
amplifier and set a summary fault. If the mask setting is Mask, then the OPS will set status to
ALARM and will log the event.
The overdrive protection mode has 4 states: N/A, OK, ALARM, FAULT.
When the overdrive protection mode is not selected (off), "N/A" is displayed in the
status.
When the overdrive protection mode is on and the forward power has not exceeded the
activation level, "OK" is displayed in the status.
When the overdrive protection mode is on and the forward power has exceeded the
activation level, "FAULT" or "ALARM is displayed in the status.
It will also be noted when the overdrive protection mode is in "FAULT" state, that the OPS
will not change the "FAULT" state if the mute is enabled, or the amplifier is off. The OPS is
assuming the operator will correct the overdrive condition by lowering the input power level
and then will disable the mute.
Notes:
1) Overdrive protection is only available in Firmware version 1.2.1 or newer.
1.3
Functional Description
Each HPOD consists of a Comtech SSPA module with a field replaceable power supply, a field
replaceable fan assembly, and the Monitor/Control Processor (MCP). The amplifier features a
Comtech low loss combining technique and MCP based temperature versus gain compensation.
Introduction
HPOD C-, X-, Ku-Band High-Power Outdoor Amplifier
1
or "OPS", which will help protect the
1–3
Revision 9
MN/HPOD.IOM
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