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Comtech EF Data CDM-760 User Manual

Page 97

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Front Panel Operation

Revision 2

CDM-760 Advanced High-Speed Trunking Modem

MN-CDM760

6–11

Interface type, Modulation type and FEC Code Rate settings. The upper range of the data rate is

also affected by the FAST option(s) installed.

The Data Rate adjusts automatically if changes made to any of the higher-priority parameters

cause the data rate to become invalid.

Table 6-3 and Table 6-4 list the available modulation and code rate combinations. These tables

have some roundoff of the last number in the Data Rate Range columns.

(CONFIG: Tx) Data Tx Symbol Rate

You can change the Tx Symbol Rate while the modem is in MultiStream Mode. The

modulator turns the Tx Carrier OFF while programming.

Tx Symbol Rate = 30000.000 ksps

()

Use the   arrow keys to select a digit, and then use the  arrow keys to change that digit.

Press ENTER.

The Data Rate value changes as you change the Symbol Rate value. The value of the Data Rate

depends upon the code rate, modulation type, and mode type.

When you change the modulation, code rate, or other parameters, the modem attempts to

maintain the same Symbol Rate as long as it is still in range when you change one of the other

parameters. The modem rejects any data or symbol rate change that is not in the valid range.

You must first change the Modulator Code Rate or mode when the modem rejects a new rate.

Table 6-3 and Table 6-4 list the available modulation and code rate combinations. These tables

have some roundoff of the last number in the Data Rate Range columns.