3010-dda.ib.rev1.doc
Page 3 of 10
05/07/2006
Description
The IRT DDA-3010 is a single input, six out 140/155 Mb/s data distribution amplifier whose input and outputs
comply with ITU Rec. G.703.
Due to the fact that standard loop through techniques used in the analogue domain are unsuitable to the digital
domain most digital equipment comes with no facility to route the input signal to other locations. As a result a DDA
is required at almost every point in the digital chain.
Serial digital signals also suffer severe deterioration over relatively short cable distances. The DDA-3010 provides a
means of extending the working distances that can be achieved by equalising, reclocking and re-transmitting the data
mid route.
The DDA-3010 provides input cable equalisation and reclocking of the serial digital signal, muting of the output
signal when no input signal is applied and external alarm contacts on loss of signal or loss of lock and loss of the
power supply.
Six individually sourced outputs are provided at the rear of the module and a monitoring port is provided on the front
panel. In the event of a power failure, a bypass relay automatically switches the input signal to output 1.
Indicators are provided on the front panel for:
Signal present.
155 Mb/s operation.
140 Mb/s operation.
Power
on.
The DDA-3010 may be mounted in IRT’s 1 RU or 3 RU frames with other analogue or digital modules.
Standard features:
•
Input and output connections on the rear panel.
•
Automatic input equalisation to 250 metres.
•
Data regeneration & re-clocking.
•
Automatic output muting on no input.
•
External alarms.
•
Front panel indicators provide monitoring of presence of input signal.
•
Front panel indication of link selection of operating rate 140 Mb/s or 155 Mb/s.
O/P 1
O/P 2
O/P 3
O/P 4
O/P 5
O/P 6
MON O/P
OUTPUTS
EQUALISER
RECLOCKING
SIGNAL FAIL
DETECTION
INPUT
Relay RL 2 = Power Loss Alarm
Link LK1
SIGNAL FAIL
ALARM O/P
RL 1
BLOCK DIAGRAM DDA-3010 SIGNAL PATH
RL1
Link LK2
POWER LOSS
ALARM O/P
RL 2
Power Loss Bypass Relay
Relay RL 1 = Signal Fail Alarm
(Loss of Lock, Loss of Signal)
Link LK4
140/155 Mb/s
Select
