Comtech EF Data SLM-5650A Installation And Operation Manual page 123

SLM-5650A Satellite Modem
Front Panel Operation
5.2.5.2 TEST: Loopback
Loopback Test Modes: Normal
Use the arrow keys to select Normal, IFℓ, or I/O1ℓ, and then press [ENT].
Loopback Test Mode
Normal
IFℓ
I/01ℓ
5.2.5.3 TEST: BERT
BERT: Tx:Off Pattern:2047
Reset Rx:Off Errs:=0000000 BER:NoSync
Use the arrow keys to select Tx, Pattern, ErrIns, Reset, Rx, Errs, or BER, and then press
[ENT]. Then, use the
BERT Mode
Tx
Pattern
ErrIns
Reset
Description
Not a test mode: Select for standard modem operation.
IF Loopback – Loops the output of the modulator back to the demodulator (inside the
modem) to verify transmit and receive configurations match as well as the data inputs
and outputs.
Baseband Loopback – Loops the transmit data (after the interface) back to the receive
data path interface. This mode is useful for checking interface cabling and clocking.
arrow keys to select the desired setting. Press [ENT] to execute the test.

Description
Select to turn the transmit test pattern generator On or Off.
Select from the available patterns:
• Mark – All ones.
• Space – All zeros.
• 1:1 – A one followed by a zero and then repeats.
• 1:2 – A one followed by two zero's and then repeats.
• 2E15-1 – A pseudo-random data pattern of 2^15 –1, compatible with standard BERTs.
• 2E20-1 – A pseudo-random data pattern of 2^20 –1, compatible with standard BERTs.
• 2E23-1 – A pseudo-random data pattern of 2^23 –1, compatible with standard BERTs.
• MIL188 – 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.
• 2047 – A pseudo-random data pattern of 2^11 –1, compatible with standard BERTs.
Select to insert a single error into the data stream by pressing [ENT].
Select to restart the BER test and clear the error and BER displays.
IFℓ
(E)
ErrIns
5–41
Revision 8
MN-SLM5650A
I/O1ℓ