User Manual

RF-Orchestra!™ Transmitter Installation and Operation Operation
July 2000 6880493G02-C 5-35
To enable DC Offset Training, write parameter 998 to 2 (RFO FIPS: w 998 2).
Power Control (RFO FIPS: w 992 1) must be enabled for DC Offset Training to function
properly
Note: Power control is enabled upon every station reset. It should only be disabled for testing
purposes.
RF-O! Ambient Temperature Monitoring
The RF-O! transmitter monitors the ambient (room) temperature, with a sensor located just
behind the LEDs on the OCM board. When correctly calibrated at about 25 degree C, the
sensor has typically less than 1 degree C error over a 100 degree C range. The RF-O!
transmitter uses the ambient temperature sensor on the OCM to determine two types of high
temperature conditions: high ambient temperature and high PA temperature.
Ambient temperature is used to cutback or shutdown power to avoid possible damage to the
PAs or other components within the transmitter. The RF-O! transmitter is specified to work at
full power from –30 to +45 degrees celsius and to derate from 0 to 3 dB between +45 and +60
C. When the temperature goes above +60 C, the transmitter automatically becomes disabled
(shutdown).
In addition, the ambient temperature signal is compared every 10 seconds to the PA
temperature read by the host processor. When the PA temperature exceeds ambient
temperature by an amount greater than the user configured trip point (called the PA vs.
Ambient Temperature 3 dB setting), an alarm and error are logged while the RF power of the
station is derated by 3 dB. If PA Temperature rises above the PA vs. Ambient Temperature
Shutdown Offset, also configurable by the user, another alarm and error are logged, and the
transmitter is disabled (shutdown).
High Ambient Temperature Cutback/Shutdown Operation
The RF-O! transmitter makes ambient temperature sensor readings every 10 seconds. The
RF-O! transmitter compares the current ambient temperature with the value stored in
parameters 3001 (Ambient Temperature Power Derate Start) and 3002 (Ambient Temperature
Power Shutdown). If the ambient temperature is greater than 3001, but less than 3002, a
cutback will occur. The amount of cutback depends on the values of 3001, 3002, and 3003
(Ambient Temperature Derate Maximum Cutback).