SAGEM-LINK F unprotected and protected configurations are obtained by using
the same basic system components :
- IDU including the user interfaces, microprocessor, multiplexer and
demultiplexer
- Cable Interface Module including DC power supply, modem and ODU cable
interface
- ODU including IDU cable interface and RF circuits (synthesizers,
transmitter, receiver)
Non-Protected 1+0 terminal with an integrated
antenna
Protected 1+1 hot standby terminal with a coupler
and an integrated antenna
The IDU, which is frequency independent, consist of a 19 inches rack,
including :
- All user interface access (tributaries, auxiliary channels, relays and
dry loops, EOW, SNMP management ports, PC serial port)
- A Microprocessor controlling the whole system, and communicating with
the ODU, the remote IDU, the SNMP agent, and the SAGEM-LINK F Pilot
software.
- A flexible E1 multiplexer / demultiplexer (2 E1, 4 E1, 8 E1, 16 E1)
- A wayside traffic multiplexer including :
- - Two Auxiliary channels (AUX1 and AUX2) : 9600 bauds with V11 / V28
interfaces (controlled by software).
- One Auxiliary channel (AUX3) : 64 kbit/s with V11 interface, that can be
configured in either co-directional or contra-directional mode
- One point to point audio Engineer Order Wire (EOW)
- Optional Ethernet 100 base T interface. When this option is present, the
IDU may configured with E1 interface only, with Ethernet interface only, or
with a combination of E1 and Ethernet. All configurations are controlled by
software.
- A network management interface compliant with SNMP protocol. The NMI
interface has three Ethernet 10 BaseT ports (internal hub), two serial ports
(MGMT1 and MGMT2), and TSL2 interface to dialog with the remote NMI
interface via an internal auxiliary radio data channel. Once the user has
configured the IP addresses and the routes, the NMI card acts as a router
for management traffic.
- In addition, there are 5 internal configurable alarm relays, and 4
Inputs / Outputs dry loops.
The IDU can contain one or two cable interface modules depending on the
system configuration. These modules are plugged into the IDU rack.
The Cable Interface module, which is frequency independent, is plugged
into an IDU rack. It consist of :
- ODU cable interface which multiplexes in frequency 5 signals in order to
transmit them on a single 50 ohm coaxial cable. These signals are :
- - DC voltage (-48V) to supply the ODU
- Transmit IF which is a QPSK or a 16QAM modulated carrier at 350 MHz
frequency
- Telemetry uplink (5.5 MHz) which contains all control signals from IDU to
ODU
- Receive IF (modulated carrier at 140 MHz)
- Telemetry downlink (10 MHz) which carries information returned from the
ODU to the IDU (alarms, receive signal level).
- A 350 MHz QPSK / 16QAM modulator including :
- An Reed Solomon FEC encoder (204, 188, 8)
- A scrambler and a digital filter
- A 350 MHz I/Q modulator
- A 140 MHz QPSK / 16QAM demodulator including :
- Zero IF down conversion
- Adaptive equalizer
- Carrier and Clock digital recovery
- Reed Solomon FEC decoder
- Descrambler
- BER indication
- A DC- DC power supply, feeding the cable interface module and the rest
of the IDU. In 1+1 systems, the IDU is supplied by two power supply from the
main and the standby cable interface modules. A hot swap feature is
implemented in order to avoid any disturbance on traffic while being in
maintenance operation.
The Outdoor Unit, which is capacity independent, is an integrated unit
consisting of :
- IDU cable Interface which is the reverse of Cable Interface module :
- DC voltage Input (-48V) to supply the ODU
- 350 MHz Transmit IF input
- Telemetry uplink (5.5 MHz) which contains all control signals from IDU to
ODU
- 140 MHz Receive IF output
- - Telemetry downlink (10 MHz) which carries information returned from
the ODU to the IDU (alarms, receive signal level).
- Transmitter using two frequency conversions. Minimum frequency step is
250 kHz
- Diplexer
- Receiver using two frequency conversion
- Power supply
- Microcontroller which controls the ODU and communicates with the IDU