R
EPEATER
F
EATURES
Dekolink™—IDEN Repeater Hardware Manual
11
No adjustments are required: When installing the repeater, the standard procedure
for the technician is to tune the repeater to the desired isolation and gain values.
With SALC, the tuning procedure is accomplished automatically, thus saving
precious workmanship and equipment usage time for a “plug & play” foolproof
deployment.
The SALC periodically learns traffic conditions, avoiding the need to remember and
store the last state after power failure. Repeaters that blindly amplify the pilot code
(minimal transmission) of a certain base station might generate network problems
(unnecessarily increase the noise in a certain cell). By keeping the same gain for
pilot only transmissions as well as for full traffic situations, the Dekolink SALC
feature minimizes this effect.
SALC Summary, Conventional iDEN repeaters often interfere in the network when
strong traffic raises the repeater input signal level, which as a result turns on the
ALC algorithm of the system. Once under ALC, the conventional system is no
longer in its linear dynamic range, hence creating interferences in the cell shrinking
or expanding procedures. The Smart ALC solves this problem and thus there is no
need for adjustments. The repeater will not interfere with the network shrinking or
expanding processes and thus become “network friendly “.
5.3. Automatic Level Control (ALC) Function
The repeater has ALC functioning on both the Uplink and Downlink power amplifiers
that prevents saturation of the power amplifier. The amplifier has a directional coupler
and a detector that monitors the output power. When a high signal is received, the ALC
detects the amplitude and sends a feedback signal to a voltage variable attenuator that
attenuates the signal level so that the output power of the amplifier does not exceed the
preset limit. This level control ensures that the power amplifier operation stays within
the linear region only, thus preventing saturation and signal distortion.
Automatic Level Control protects the amplifiers from overloading and prevents the
system from generating spurious emissions. ALC limits the output power to a constant
value (Maximum output power). The output power is sampled, decoupled, rectified and
used to control the attenuator network in the RF modules.
