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B.1.3.8 demodulator rate, B.1.3.8.1 demodulator filter rate assignment – Comtech EF Data SDM-650B User Manual

Page 185

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SDM-650B Satellite Modem

Remote Control Operation

Rev. 6

B–9

B.1.3.8 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.

Notes: For variable rate demodulator option:

1. 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.

2. 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.

B.1.3.8.1 Demodulator Filter Rate Assignment

Command:

Response:

>add/ADRx_nnn_mmmm.m”cr””lf”]

Status Only: Response:

>add/ADRx_nnn_mmmm.m”cr””lf”]

Where:

x = A, B, C, or D (Filter designator).
nnn = 1/2, 3/4, 7/8, or BP12 (Decoder rate).
mmmm.m = 9.6 to 4080.0 (Data rate).


Note: The parameters “nnn_mmmm.m” may be replaced by “N/A” to indicate “no
assignment.”

Example:

Command:

Response:

>add/ADRx_N/A”cr””lf”]