BDA OVERVIEW:
The BDA assembly extends the coverage area of radio communications in buildings
and RF shielded environments.
The unit features low noise figure and wide dynamic range. It is a multi-block system,
based on a dual-duplexed (quadruplexer) path configuration with sharp out of band
attenuation allowing improved isolation between the receiving and transmitting paths,
plus ESMR 800 and SMR 900 paths.
The BDA has an integrated re-banding switch to change the frequency of operation in
the ESMR 800 band.
BDA BLOCK DIAGRAM DESCRIPTION:
Refer to figure 1 for the following discussion.
The BDA Downlink path receives RF signals from the base station and amplifies and
transmits them to the subscriber. The BDA Uplink path receives RF signals from the
subscriber and amplifies and transmits them to the base station.
For SMR distinct frequency bands; ESMR 800 frequency bands are as follows: (806-
824 MHz) for the Uplink and (851-869 MHz) for the Downlink
.
SMR 900 frequency
bands are as follows: (896-901 MHz) for the Uplink and (935-94
0
MHz) for the
Downlink
.
A quadruplexer isolates the Uplink and Downlink paths in the SMR chain,
plus a switched
*
internal duplexer will change the ESMR 800 frequency band to its re-
banding frequency range.
A selectable Automatic Level Control (ALC) allows for output power limiting. A variable
step attenuator gives 0 – 30 dB of attenuation in 2 dB steps. The use of these controls
is covered in the “OPERATION” section, later in this document.
*Re-banding Switch
The re-banding switch changes the frequency of operation in the ESMR 800 band to
Uplink (817-824 MHz) and Downlink (862-869 MHz). There is no tuning require, just
select the narrow SMR position for re-banding frequencies. (See Figure 5)
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