Q-Lite Satellite Modem Installation and Operating Handbook
11-2
11.1 Transmit Faults
Fault Text
Notes
Relays To Ter To Sat
Other
Tx fault: External Tx clock
selected, but no clock
from interface.
The modem is set to use an external clock but no clock is
being provided. The clock generation will use the internal
clock as a backup to maintain the carrier and signal
integrity. Check the data connector is attached and check
for activity on the clock input lines.
T
TB
SA,SC
Tx fault: Data Ready Input
active.
The DRI line has been de-asserted by the data source
feeding the modem, indicating a unit fault with data
source.
T
Tx fault: Signal Valid Input
active.
The SVI line has been de-asserted by the data source
feeding the modem, indicating it wished to disable
transmission. If the carrier is set to RTS Enabled the
carrier will be muted.
T
Tx fault: Data input is all
ones
(AIS),
indicating
upstream equipment fault.
The data supplied to the modem is all ones (AIS). This is
normally used to indicate an upstream equipment fault. It
is not a modem fault. This alarm can be switched off if
required
using
the
Edit->Unit->Advanced->Alarms-
>Actions
menu.
T
TB
SA,SC,
Tx fault: Frame sync lost
on Tx input. Check bearer
type and AIS.
The modem detects frame synchronisation when the Drop
MUX is active (or 2048k IBS G.732 mode is enabled).
Check the bearer type is specified correctly. This fault
normally occurs only when there are significant errors on
the terrestrial link or when the signal is supplied with AIS
and the modem is set to ignore AIS. Check that the AIS
detector is not disabled. There is an option to make the
modem re-seek frame synchronisation when CRC
synchronisation is lost - check the modem is not set to
expect a CRC and is forcing frame re-acquisition when
CRC is lost but there is no CRC on the PCM signal.
T
TB
SA,SC
Tx fault: Dropped data is
all ones (AIS), indicating
upstream equipment fault.
The specific timeslots dropped by the Drop MUX contain
all ones (AIS). This is different to the ‘Tx Fault: Data input
is all ones (AIS)’ message described above which refers
to the whole PCM bearer being AIS. In this case, it is only
the specific dropped timeslots that contain AIS. This is
normally used to indicate an upstream equipment fault - it
is not a modem fault.
T
TB
SA
Tx fault: CRC sync loss
on Tx input.
The modem only seeks Cyclic Redundancy Code (CRC)
sync when the Tx baseband is set to use the Drop mux in
G.732 mode (or 2048k IBS G.732 0% overhead mode)
and when set by the user to process CRC’s. If CRC sync
is permanently lost, check if a CRC is present on the PCM
signal.
T
Tx fault: Input BER > 1E-
3.
The Bit Error Rate at the Tx input (measured on the PCM
Frame Alignment Words) is worse than 1x10
-3
. This can
only be due to a very poor error rate on the PCM input
signal.
T
TB
SA
Tx fault: TS16 MF sync
lost on Tx input
The modem only seeks TS16 Multiframe sync when the
Tx baseband is set to use the Drop mux in a G.732 mode
and CAS signalling has been selected (or 2048k IBS
G.732 0% overhead mode with CAS is enabled). Check
that a CAS multiframe is present on the PCM signal
applied to the modem
T
TB/TE
SC
Tx fault: Frame sync lost
on Tx input. Check bearer
type and AIS.
Frame sync has been lost on the terrestrial input. Only
displayed when using the drop mux. Check the bearer
type has been correctly configured. If the AIS detectors
are disabled check equipment generating bearer is not
generating AIS.
T
Tx fault: Frame sync lost
on ports (1 to 4).
Frame sync has been lost on one or more of the Quad E1
card terrestrial inputs.
T
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Страница 233: ...Q Lite Satellite Modem Installation and Operating Handbook 12 11 Figure 12 2 PER for DVB S2 Short Frames ...
Страница 234: ...Q Lite Satellite Modem Installation and Operating Handbook 12 12 Figure 12 3 PER for DVB S2X Normal Frames ...
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