User's Manual

P.G. TM0040AE
2-4
2.2.3 Fault Conditions
- The A289 circuitry monitors four separate parameters in the
unit. These are: (a) the bias currents drawn by devices in the cellular and PCS amplifiers
and, (b) the presence of downlink RF output power in each amplifier band. Each function
can be disabled as described in Section 4, if the unit is being used in a restricted
operational mode.
The DC current monitoring triggers a fault condition if the DC bias current deviates outside
predetermined high or low current limits.
The downlink RF output power from each frequency band is monitored by separate
detectors and a FAULT condition is triggered if the level in either band drops below a
nominal level of + 5 dBm. If the amplifier is to be installed at a point in the system where
the output power in either band may be less than + 7 dBm, then the RF monitor circuit for
the appropriate band should be disabled as described in Section 4 herein.
The local fault indicators indicate specific faults as follows:
CELL
BIAS Bias fault in the Cellular amplifier
PWR Low downlink RF power from the Cellular amplifier.
PCS
BIAS Bias fault in the PCS amplifier
PWR Low downlink RF power from the PCS amplifier