Q-Flex Satellite Modem Installation and Operating Handbook
6-90
Figure 6-48 View->SAF Screen
6.2.11 Test Screen
The
Test
screens (shown in
Figure 6-49
and
Figure 6-50
) supports the following test
functions:
•
Loopback.
This allows selection of internal loopback between the transmit and receive
paths, at different points in the processing chain. This provides a convenient way of
checking modem operation in isolation from other equipment. Local loopback refers to
returning local signals traveling within the modem in the direction of the satellite, back
towards the terrestrial interface. Remote loopback refers to returning remote signals
traveling in the direction of the terrestrial interface, back towards the satellite interface.
•
RF Test Modes.
This provides two types of signal – a CW (pure carrier) signal and an
alternate 1,0 signal – that can be used to test modem operation.
•
IP Packet Satellite Delay.
This allows a one-way satellite delay (in milliseconds) to be
entered. This can be used in modem back-to-back testing to simulate the normal
satellite delay. It applies to IP traffic only. It should always be set to 0 when using IP
over satellite. Note that the use of this feature is currently incompatible with the use of
IP traffic shaping (as the two features compete for the same internal resources).
•
BER test.
This feature provides the ability to inject a test pattern into the modem,
through the main traffic channel or via an overhead channel and to monitor the results,
using the modem’s internal Pseudo-Random-Bit-Sequence (PRBS) Bit Error Rate
(BER) Tester.