Comtech EF Data CDM-700 - Manual (Page 68)

CDM-700 High Speed Satellite Modem Revision 5
Front Panel Operation MN/CDM700.IOM
6–14
Tx:
Æ Freq
Tx Freq: 0140.0000 MHz
(E)
Edit the Tx IF Frequency by selecting the digit to be edited, using the ◄ ► arrow keys. The value
of the digit is then changed using the ▲ ▼ arrow keys. Press
ENTER .
70/140 MHz
The ranges of frequencies are from 52 to 88 MHz and from 104 to 176
MHz with a resolution of 100 Hz.
L-Band
The range of frequency is from 950 to 1950 MHz with 100 Hz resolution.
Tx:
Æ Data
Tx Comp Data Rate(Mbps)
000.000000
(E)
This is a ‘read only’ status window that displays the Composite Data Rate, the sum of data rates
for all enabled Tx ports on Intfc1 and Intfc2 as measured at the data input connector (customer
interface). Referring to the next menu, the Symbol Rate is the rate transmitted at the Tx IF
connector and corresponds to the Composite Data Rate plus overhead (2.5%), and includes the
effects of coding and modulation.
Composite Data Rate = ∑ Port-Data Rates, where:
Ports = all enabled ports for Intfc1 and Intfc2 and depends upon the interfaces
installed in Slot 1 and Slot 2.
Symbol Rate = 1.025 *Composite Data Rate /(m *CR), where:
m = the modulation index (2 for QPSK, 2 for 8-PSK, 4 for 16-QAM, 5 for
32-QAM, 6 for 64-QAM),
and
CR = Code Rate (3/4, etc)
Programming of this modem is not the same as conventional modems because the architecture
differs. The incorporation of an internal statistical multiplexer/demultiplexer, and the multi-port
interfaces makes the configuration more consistent if the user sets the data rate for each port on
the interface. The data rate for each port is programmed under the CONFIG: Intfc1 and
CONFIG: Intfc2 menus.
Press
ENTER
or
CLEAR
to return to the previous menu.