Sweep Reacquisition; Fast Acquisition Mode - Comtech EF Data SDM-650B Installation And Operation Manual

Remote Control Operation
B.1.3.21 Sweep Reacquisition
This command is used to specify time duration of the reacquisition mode. The sweep is
reduced to ± 2500 Hz of the last known lock point. Use of this function may reduce
reacquisition times at low data rates. To inhibit the sweep reacquisition mode, set
"SR" to 0 seconds.
Command:
Response:
Status Only: <add/SR_"cr"
Response:
B.1.3.22 Fast Acquisition Mode
This command is used to enable or disable fast acquisition and directed sweep modes of
operation.
When fast acquisition is enabled, the fast acquisition algorithm (which requires hardware
calibration) is used for acquisition of receive symbol rates of 128 kbit/s or lower.
However, if the sweep range is set to less than 50 kHz, acquisition will be dictated by the
directed sweep specifications, and the fast acquisition algorithm will not be used.
The directed sweep functions are also available when fast acquisition is enabled. Directed
sweep provides three commands for manipulating the acquisition process. These
commands are:
•
•
•
Note: These commands will be discussed in later sections.
Command:
Response:
Status Only: <add/FAM_"cr"
Response:
B–14
<add/SR_xxx"cr"
>add/SR_xxx"cr""lf"]
>add/SR_xxx"cr""lf"]
Where: xxx = 0 to 999 (number of seconds).
SCF_ (Sweep Center Frequency)
SWR_ (Sweep Range)
SD_ (Sweep Direction)
<add/FAM_xxx"cr"
>add/FAM_xxx"cr""lf"]
>add/FAM_xxx"cr""lf"]
Where: xxx = ON or OFF (OFF disables fast acquisition and directed sweep modes).
SDM-650B Satellite Modem
Rev. 6