Reed-Solomon Correction Off; 2047 And Mil-188 Test Patterns - Comtech EF Data SLM-7650 Installation And Operation Manual

SLM-7650 Satellite Modem
Maintenance
5.3.4.4

Reed-Solomon Correction OFF

The Reed-Solomon (R-S) decoder data error correction circuitry can be disabled without
removing the overhead associated with the R-S FEC. When R-S Correction is set to OFF
(Configuration-Demodulator menu) the data flow is then routed through normal data
paths without R-S error corrections. Only Viterbi error correction will be active. This test
mode will allow a more timely verification of link performance.
5.3.4.5

2047 and MIL-188 Test Patterns

The operator is capable of substituting a test pattern on the transmit side and monitoring
on the receive side of the modem. These test pattern can be used as a quick BER
performance test to verify that the link performance is operating at a reasonable error
rate. The BER performance is read in the Monitor-2047 error menu. If the carrier is not
locked, the Monitor menu will display 'No Data'. The normal setting for both the TX
2047 Pattern and the RX 2047 Pattern is NONE.
The '2047' setting is a standard pattern compatible with a Fireberd BERT.
The 'MIL-188' setting is a modified 2047 pattern that is used to test the Data Source Sync
function of the modem. It has the maximum number of consecutive zeros that the
modem can handle when recovering the clock from the data transitions.
This test mode will affect the transmit side of the modem by switching from the incoming
data stream to the internal pattern generator. The receive side of the modem is not
affected and is only a monitor of the recovered satellite data steam.
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