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 54 of 114
4.9. Quadplexer (DAS) 60-228706
Quadplexer (DAS) 60-228706 is built into a 4U, 19” rack-mount case
Band 1 Downlink RF from the 8 Ch. Squelch Gated BDA 60-228704 enters the shelf via the N type port
labeled “A” (annotated “A” in section 4.9.4.) and 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 1 Downlink link path is then combined with that of the Band 1 Uplink path by means of
critical harness.
Band 2 Downlink RF from the 8 Ch. Squelch Gated BDA 60-228705 enters the shelf via the N type port
labeled “C” (annotated “B” in section 4.9.4.) and 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 Band 2 Downlink link path is then combined with that of the Band 2 Uplink path by means of critical
harness and the High and Band 1 Downlink paths are then combined again by means of critical harness and
the combined Downlink path passes through 30dB Directional Coupler 90-852330 which couples off a small
portion of the Downlink signal and feeds it to the N type port labeled “MONITORING” (annotated “D” in
section 4.9.4.) providing a 30dB test/monitor port for the Downlink signal.
The main Downlink signal then exits the shelf via the N type port labeled “DAS” (annotated “C” in section
4.9.4.) and the signal is fed to the N type connector labeled “DAS PORT” on the rack lid (annotated “C” in
section 4.3.3.).
Uplink RF from the DAS enters the rack via the N type connector labeled “DAS PORT” on the rack lid
(annotated “C” in section 4.3.3.) and the signal is fed to the N type port on the Quadplexer front panel
labeled “DAS” (annotated “C” in section 4.9.4.). The signal path passes through 30dB Directional Coupler
90-852330 which is used to provide a test/monitor port for the Downlink signal and then the signal path is
split into two branches (Band 2 and Band 1) 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
Uplink path passes through a Bandpass Filter 02-016801 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 2 branch is also further split by critical harness into Uplink and Downlink paths and the Band 2
Uplink path passes through a Bandpass Filter 02-013401 which is tuned to pass the Band 2 Uplink
passband of U/L 499.3MHz to 499.7MHz and to reject out-of-band signals and noise.
The two Uplink paths, High and Band 1 then exit the Quadplexer for their respective BDAs; the Band 1
Uplink exits the shelf for 8 Ch. Squelch Gated BDA 60-228704 via the N type port labeled “B” (annotated “E”
in section 4.9.4.) and the Band 2 Uplink exits the shelf for 8 Ch. Squelch Gated BDA 60-228705 via the N
type port labeled “D” (annotated “F” in section 4.9.4.)