Fiplex TETRA Compact, Руководство пользователя и инструкция по установке

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UM-0100-03.09 – August 2010 12
4. AGC UL
Blinking condition indicates that AGC circuitry is active for uplink path. For further information
please read Automatic Gain Control (AGC) latter in this chapter.
5. Overload DL
Led permanently ON indicates that Overload protection circuitry for downlink path is active.
For further information please read Overload Protection latter in this chapter.
6. Overload UL
Led permanently ON indicates that Overload protection circuitry for uplink path is active.
For further information please read Overload Protection latter in this chapter.
Automatic Gain Control (AGC)
Automatic Gain Control circuitry is intended to keep repeater’s output power at a fixed level when input
signals exceed maximum values, avoiding quality signal degradation by intermodulation generation.
When AGC is active AGC leds from UL or DL (or both) will blink, this means that signal level from donor
site (or from service area) plus repeater gain produces an output power that is above the maximum
composite output power of the repeater. This should not be considered an undesired working condition, far
from that; this is the best operating condition because you are getting the maximum composite output
power available from the repeater.
Anyway is a good practice to increase attenuation (reducing gain), until AGC led turns off, this operation
releases AGC circuitry dynamic range.
Also is a good practice to check signals from donor site to ensure that undesired signals are not being
amplified by the repeater, or even desired signal levels are not excessively high taking repeater to an
overload condition.
Overload Protection
When AGC circuit reaches its limit, the power amplifier stage is shut down to prevent harmful distortion and
potential damage to the repeater. After approximately ten seconds the system checks if overload condition
is still present, if this happens amplifiers will remain off. This cyclic check will continue until condition that
makes AGC circuitry reach its limits disappears.
Conditions that can cause AGC to reach its limits include the presence of one or more very strong
channels, a strong in-band noise source, or amplifier oscillation due to poor antenna isolation.
When overload protection lower row led from UL or DL (or both) will be ON permanently.
Laboratory Measurements
For specific parameters verification and laboratory tests, please contact factory.
Detailed procedures, recommended tests set up, and a knowledge engineering team will bring adequate
support to perform this measurements in a comfortable and safely way
.