Comtech EF Data CDM-750, Installation And Operation Manual

Page: 103 / 300

CDM-750 Advanced High-Speed Trunking Modem Revision 2
Front Panel Operation MN-CDM750
5–27
5.2.2.3.4 (CONFIG) Rx: Mod (Modulation)
Modcod=QPSK 1/2 Read Only
This read ‐ only screen identifies the active modulation type. Press ENTER or CLEAR to return to
the previous menu.
5.2.2.3.5 (CONFIG) Rx: Data
Rx Data Rate Rx Symbol Rate
( )
Use the
W X
arrows keys to select Rx Data Rate or Rx Symbol Rate , and then press ENTER .
(CONFIG) Rx: Data
Æ
Rx Data Rate
Rx Data Rate = 070000.000 kbps
(
v
)
This read ‐ only screen identifies the active Rx Data Rate. To properly lock an Rx path and
automatically obtain the Rx Data Rate, you need to make changes as necessary to the Rx Symbol
Rate, Gold ‐ n Index Code (Goldcode), and Rx IF Frequency of the modem. Press ENTER or CLEAR to
return to the previous menu.
(CONFIG) Rx: Data
Æ
Rx Symbol Rate
Rx Symbol Rate = 30000.000 ksps
(
v
)
To change the Symbol Rate: First, use the
W X
arrow keys to select a digit to edit, and then use
the
ST
arrow keys to change that digit. Press ENTER when done.
Once the Rx path is synchronized, the correct data rate, modulation type, code rate, pilots
ON/OFF, FEC frame length spectral inversion, etc. appear in the appropriate Rx menus.
5.2.2.3.6 (CONFIG) Rx: Pilot
In order to properly lock to a carrier, it is critical that the Rx Goldcode value
matches the Tx Goldcode value of the distant end modem.
Rx: Pilot=Off Read Only
Goldcode=000000
(
v
)