Comtech EF Data SDM-650B - Manual (Page 319)

SDM-650B Satellite Modem Trojan Interface
Rev. 5 G–23
G.6.4.2 Demodulator
G.6.4.2.1 Set Demodulator Frequency
Command:
Response: >add/DF_nnn.nnnn”cr””lf”]
Status Only: Response:
>add/DF_nnn.nnnn”cr””lf”]
Where: For the 140 MGz modulator, nnn.nnnn = 50.0000 to 90.0000, and 100.0000 to
180.0000.
G.6.4.2.2 Demodulator Rate
The demodulator has four symbol rate filters. Each filter is for a specific symbol rate. The
data rate and decoder rate for each filter must be established upon initial demodulator
installation, and when circumstances indicate the need to do so.
Filters are designated as A, B, C, and D. If a filter is not physically present in the system, it
may be assigned “N/A” (not assigned).
Additionally, filters which are factory programmed may not be remotely programmed, and
will return the “error 5” message when a programming command is issued.
Demodulators with the variable rate option installed may have four preprogrammed rates
available by using the filter rate assignment commands. These rates are selected using the
standard “SDRx_” commands. Modems that have the variable rate option installed will also
respond to the special “SDRV_” command. This allows for truly variable rate control while
maintaining compatibility with previous systems.