Comtech EF Data SDM-309B - Manual (Page 145)

SDM-309B Satellite Modem Theory of Operation
MN/U-SDM309B Rev. # 5-5–21
5.4.3 Fast Acquisition
When Fast Acquisition is enabled the fast acquisition algorithm is used for acquisition of
receive symbol rates of 128 Kbps or lower. If the sweep range is set to less than 50KHz,
acquisition will be dictated by the directed sweep specifications and the fast acquisition
algorithm will not be used.
5.4.4 Directed Sweep
The directed sweep mode was designed to rapidly acquire a carrier of known frequency
offset. If the customer knows where the carrier is going to be, the Directed Sweep Mode
can be much faster than the Fast Acquisition Mode. Due to the reduced speed of the
lower data rates, (up to 30 seconds in fast acquisition) the customer has the option of
controlling the sweep functions. There are four additional functions in the front panel
menu that are directly related to the directed sweep mode. There is a monitor function,
SWP_FREQ, that detects the current sweep frequency and there are three functions in
the configuration menu that are specifically for the directed sweep mode. They are,
Sweep Center, Sweep Range, and Sweep Direction. These functions only show up in the
front panel menu when the Fast Acquisition function has been turned ON in the “Utility”
menu. Refer to the Front Panel Operation instructions for further details of the directed
sweep functions.