User Manual

Axell Wireless Limited
Technical Literature
L.A. M.T.A. Remote Sites
Document Number 80-301401HBKM Issue No. 1 Date 13/06/2008 Page 41 of 148
3.5. UHF BDA Unit (80-301404)
UHF BDA Unit (80-301404) provides the amplification stages for the UHF Midband and UHF
Highband paths, The unit is housed in a wall mount case 600x600x250mm (24” x 24” x 10” approx).
The Downlink UHF Midband signal is received at the port labelled “UHF MID D/L INPUT” (Annotated
A in the picture in section 3.5.4.2.). The signal passes through a switched attenuator providing 0 to 30
dB of RF signal attenuation and then into the amplification stage. The Downlink UHF Midband
amplification stage is provided by two amplifier modules, the first is a 15dB gain Low Power Amplifier
and the second is a 20W, 23dB gain power amplifier. Both amplification stages are straddled by an
Automatic Gain Control assembly providing limiting to the output signals in the case of high input
signals.
The input to the AGC detector is provided by the output of a 30dB tap. After leaving the
Amplification/AGC stage the Downlink UHF Midband signal exits the BDA via the port labelled “UHF
MID D/L OUTPUT” (B in section 3.5.4.2.).
The Uplink UHF Midband signal is received at the port labelled “UHF MID U/L INPUT” (D in section
3.5.4.2.). The signal passes into a Low Noise Amplifier providing 15dB of gain and then into a
switched attenuator providing 0 to 30 dB of RF signal attenuation. After the attenuator the Uplink UHF
Midband signal passes into a second stage of amplification provided by a 5W, 30dB gain Power
Amplifier, this amplification stage is straddled by an Automatic Gain Control assembly providing
limiting to the output signals in the case of high input signals.
The Uplink UHF Midband signal exits the BDA via the port labelled “UHF MID U/L OUTPUT” (C in
section 3.5.4.2.).
The Downlink UHF Highband signal is received at the port labelled “UHF HIGH D/L INPUT”
(Annotated G in the picture in section 3.5.4.2.). The signal passes through a switched attenuator
providing 0 to 30 dB of RF signal attenuation and then into the amplification stage. The Downlink UHF
Highband amplification stage is provided by two amplifier modules, the first is a 15dB gain Low Power
Amplifier and the second is a 20W, 23dB gain power amplifier. Both amplification stages are straddled
by an Automatic Gain Control assembly providing limiting to the output signals in the case of high
input signals.
The input to the AGC detector is provided by the output of a 30dB tap. After leaving the
Amplification/AGC stage the Downlink UHF Highband signal exits the BDA via the port labelled “UHF
HIGH D/L OUTPUT” (H in section 3.5.4.2.).
The Uplink UHF Highband signal is received at the port labelled “UHF HIGH U/L INPUT” (E in section
3.5.4.2.). The signal passes into a Low Noise Amplifier providing 15dB of gain and then into a
switched attenuator providing 0 to 30 dB of RF signal attenuation. After the attenuator the Uplink UHF
Highband signal passes into a second stage of amplification provided by a 5W, 30dB gain Power
Amplifier, this amplification stage is straddled by an Automatic Gain Control assembly providing
limiting to the output signals in the case of high input signals.
The Uplink UHF Highband signal exits the BDA via the port labelled “UHF HIGH U/L OUTPUT” (F in
section 3.5.4.2.).
UHF BDA Unit (80-301404) is provided with a 24V DC input to power the amplifier modules within and
those amplifier modules are configured to provide alarm status reports. Separate alarm contact
outputs are provided for the UHF Midband and the UHF Highband paths.