1+1 Verification (Optional) - Sagem -LINK F Installation And Operation Manual

SAGEM-LINK F
Installation and Operation Manual

2.8 - 1+1 Verification (optional)

1+1 systems require additional tests compared to unprotected systems. These tests are made to verify
main and stand by units, and switches proper operation.
These tests are made on both sides of the link. As a remote switch control is not available for security
reasons, this test may require the presence of people on both sides of the link.
In hot standby mode, only one transmitter is active at a time. For a 1+1 system in frequency diversity
mode, both transmitter are active, and only receiver switchings are to be made.
In normal operation with revertive switching on, and without any alarms, the active transmitters and
receivers are the main units.
Du to the use of an asymmetrical coupler, the transmit power at antenna access and the receive
signal level at ODU access depend on the switches positions. For a 6 dB coupler, the difference
between the main and standby unit is around 5 dB.
In the figures below, active transmitter and receiver are written in bold characters.
From the local terminal, connect a BER analyzer on a 2 Mbit/s tributary and make a remote loopback
for this tributary. There should not be any error during one minute.
From the local terminal in super user mode, select the menu "Tools/Diagnostic Tools/Equipment
Forcing" to access to the manual switching mode (refer to Chapter 3 section 3.3.7.2).
Select standby receiver by clicking on the Rx2 case, and validate.
Figure 2.3 : Main local transmitter and standby local receiver active
This switching should be error free. Wait one minute to verify the transmission is error free.
From the local terminal, in the same menu, select standby transmitter by clicking on the case "Tx2".
This switching causes errors. However the switching time should be less than 2 seconds (less than 2 x
6
10 errors).
Reproduction and communication prohibited without the written permission of Sagem Communication
Tx Main (L)
Rx Main (L)
Tx Standby (L)
Rx Standby (L)
Figure 2.2 : Main local transmitter and receiver active
Tx Main (L)
Rx Main (L)
Tx Standby (L)
Rx Standby (L)
288055571-04
Tx Main (R)
Rx Main (R)
Tx Standby (R)
Rx Standby (R)
Tx Main (R)
Rx Main (R)
Tx Standby (R)
Rx Standby (R)
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Issue 04 : July 2005