SLM-5650 Satellite Modem
Revision 2
Front Panel Operation
MN/SLM5650.IOM
4–27
4.3.3.1
Select: Test: BERT
Tx
Permits the user to turn the transmit test pattern generator
On or Off
.
Pattern
Mark
Space
1:1
1:3
2E15-1
2E20-1
2E23-1
MIL188
2047
Permits the user to select a number of test data patterns.
Means, all one’s.
Means, all zero’s.
Means, a one followed by a zero and then repeats.
Means, a one followed by two zero’s and then repeats.
A pseudo-random data pattern of 2^15 –1, compatible with standard BERT’s.
A pseudo-random data pattern of 2^20 –1, compatible with standard BERT’s.
A pseudo-random data pattern of 2^23 –1, compatible with standard BERT’s.
A modified pseudo-random data pattern of 2^11 –1, compatible with the MIL-
188-165 test data pattern requirement of a continuous stream of 50 zero’s every
10,000 bits. This pattern has 5 normal 2047 patterns, with the fifth patterns
longest string of zero’s (11) stretched an additional 39 bits to create a lack of
transitions for 50 bits approximately every 10,000 bits.
A pseudo-random data pattern of 2^11 –1, compatible with standard BERT’s.
ErrIns
Permits the user to insert a single error in the data stream, by pressing enter.
Reset
Permits the user to restart the BER test and clear the error and BER displays.
Rx
Permits the user to turn on the receive bit error test set.
Errs
Permits the user to view the absolute number of errors counted.
BER
Permits the user to view the bit error rate as measured by the modem.
IMPORTANT
The BER function can work with a firebird supplying the transmit data
test pattern, while only turning on the Rx bit error rate tester. The
transmit test pattern generator can be turned on at the far end of the
link and as long as the test patterns match the Rx BERT can measure
the BER of the link. An external bit error test set can be used even
when the internal bit error test set is enabled. If AIS is enabled the data
will be over written with all one’s.
BERT: Tx:Off Pattern:2047 ErrIns (
ef
E)
Reset Rx:Off Errs:=0000000 BER:NoSync
