Comtech EF Data VMS v3.12.x Vipersat - Manual (Page 264)

Network MN/22156, rev 12
4-46 VMS User Guide
On the CDM-800, this setting applies only to transmit due to its lone transmit-
ter. Similarly, on the CDD-880 this setting only applies to the demodulator
receive. The CDM-840 provides both a Tx and a Rx setting.
Demod Select
This parameter appears for CDD-880 units only.
Specify the demodulator for this unit that will be utilized for the test.
Pattern
A choice of two pseudo-random test patterns are available, 2^23-1 or 2047 .
The first pattern, 2 23 -1, is primarily intended for error and jitter measurements at
bit rates of 34,368 kbps and 139,264 kbps (equipment operating at the primary
rate and above). A maximum of 22 consecutive zeros and 23 consecutive ones
are generated; pattern length is 8,388,607 bits.
The second pattern, 2047 (2
11 -1), is primarily intended for error measurements
at bit rates of 64 kbps and N*64 kbps (error performance at bit rates below the
primary rate). A maximum of 10 consecutive zeros and 11 consecutive ones are
generated; pattern length is 2,047 bits.
Test Mode
This parameter appears for CDM-800 and CDM-840 units.
Select the desired mode of test:
• Normal – BERT is Off.
This is the setting for normal terminal operation.
• Tx CW – transmits a continuous unmodulated wave.
Satellite provider can check for problems with cross-polarization,
power, etc. with a clean and calibrated signal.
• Tx Alternate 1/0 – transmits continuous stream of alternating ones and
zeros.
• WAN Packet Loopback – available for CDM-840 only.
Loopback test for the WAN transmit and receive interfaces.
Network | IGMP
This menu item appears for CDM-840 units only.