Handbook

Axell Wireless Limited
Technical Literature
WMATA CRCS Redundant Antenna System
General Overview
Document Number 60-228701HBK Issue No. 3 Date 28/05/2010 Page 27 of 114
4.4. Quadplexer (Base) 60-228706
Quadplexer (Base) 60-228706 is built into a 4U, 19” rack-mount case
Downlink RF from the BTS enters the rack via the N type connector labeled “BASE PORT” on the rack lid
(annotated “A” in section 4.3.3.) and the signal is fed to the N type port on the Quadplexer front panel
labeled “BASE” (annotated A” in section 4.4.4.). The signal path passes through 30dB Directional Coupler
90-852330 which is used to provide a test/monitor port for the Uplink signal and then the signal path is split
into two branches, Band 1 and Band 2, by means of critical harness.
The Band 1 branch is then further split by critical harness into Uplink and Downlink paths and the Band 1
Downlink path passes through a Bandpass Filter 02-016801 which is tuned to pass the Band 1 Downlink
passband of 489.5MHz to 491.0MHz and to reject out-of-band signals and noise.
The Band 2 branch is also further split by critical harness into Uplink and Downlink paths and the Band 2
Downlink path passes through a Bandpass Filter 02-013401 which is tuned to pass the Band 2 Downlink
passband of 496.3MHz to 496.7MHz and to reject out-of-band signals and noise.
The two Downlink paths, Band 1 and Band 2 then exit the Quadplexer for their respective BDAs; the Band 1
Downlink exits the shelf for 8 Ch. Squelch Gated BDA 60-228704 via the N type port labeled “A” (annotated
“B” in section 4.4.4.) and the Band 2 Downlink exits the shelf for 8 Ch. Squelch Gated BDA 60-228705 via
the N type port labeled “C” (annotated “C” in section 4.4.4.)
The Band 1 Uplink from 8 Ch. Squelch Gated BDA 60-228704 enters the shelf via the N type port labeled
“B” (annotated “D” in section 4.4.4.) and passes through a Bandpass Filter 02-013401 which is tuned to
pass the Band 1 Uplink passband of 492.5MHz to 494.0MHz and to reject out-of-band signals and noise.
The Band 1 Uplink path is then combined with that of the Band 1 Downlink path by means of critical
harness.
The Band 2 Uplink from 8 Ch. Squelch Gated BDA 60-228705 enters the shelf via the N type port labeled
“D” (annotated “E” in section 4.4.4.) and passes through a Bandpass Filter 02-013401 which is tuned to
pass the Band 2 Uplink passband of 499.3MHz to 499.7MHz and to reject out-of-band signals and noise.
The Band 2 Uplink path is then combined with that of the Band 2 Downlink path by means of critical harness
and the Band 1 and Band 2 Uplink paths are then combined again by means of critical harness and the
combined Uplink path passes through the 30dB Directional Coupler 90-852330 which couples off a small
portion of the Uplink signal and feeds it to the N type port labeled “MONITORING” (annotated “F” in section
4.4.4.) providing a 30dB test/monitor port for the Uplink signal. The main Uplink signal then exits the shelf
via the N type port labeled “BASE” (annotated “A” in section 4.4.4.) and the signal is fed to the N type
connector labeled “BASE PORT” on the rack lid (annotated “A” in section 4.3.3.).