User’s Manual for Repeater
MR303D Varia
M0041A8B.doc
Id.-No. 153114
Page 10
26-Oct-2000
1.4 Uplink
The uplink signals are received by the antenna and fed into the repeater where a
pre-selection of the frequency is made. The signals are then converted down to IF by
means of a mixer and an IF filter provides the selectivity against other frequencies.
After the re-conversion the signals are amplified in an amplifier that provides the
output power. The signals are then fed to the antenna via the duplexer.
In this link, an ALC and an automatic power adjust circuit (APAC) is provided. APAC
limits the output power if two carriers are present at the one UL input. This again
keeps intermodulations to the desired limit. The repeaters with Id.-Nos. 152797 &
154595 provide an attenuation selection unit, which allows the gain to be set on UL
and DL -simultaneously, but not separately- by introducing attenuation into the
amplifier chain. (See chapter 3.2 Setting the Attenuation).
In the MR303D the bandwidth of the RF modules can be set within the GSM900
band to a desired value with rotary-switches on the outside of the modules. To set a
defined bandwidth, the start channel, as well as the stop channel must be adjusted
with the rotary-switches. (See chapter 3.1 Adjusting the Frequency).
