Comtech EF Data SDM-650B - Manual (Page 322)

Trojan Interface SDM-650B Satellite Modem
G–26 Rev. 5
G.6.4.2.7 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 (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 “SCF_” (sweep center frequency), “SWR_” (sweep range), and “SD_” (sweep
direction).
Command:
Response: >add/FAM_xxx”cr””lf”]
Status Only: Response:
>add/FAM_xxx”cr””lf”]
Where: xxx = ON or OFF (OFF disables fast acquisition and directed sweep modes).
G.6.4.2.8 Sweep Center Frequency
This command sets the sweep center frequency. During carrier acquisition, the sweep starts
at an offset which is one-half the currently programmed sweep range (SWR_) from the
sweep center frequency. The direction of the offset is determined by the currently
programmed sweep direction (SD_).
The sweep center frequency may be set in the range of +25000 to -25000 Hz.
Command:
Response: >add/SCF_xnnnnn”cr””lf”]
Status Only: Response:
>add/SCF_xnnnnn”cr””lf”]
Where:
x = + or - (sweep offset direction).
nnnnn = 0 to 25000.
Note: This command is only valid when Fast Acquisition is enabled. See the “FAM_”
command definition.