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Emitter Audio
2.3.2
Circular
The Circular scan describes an emitter whose antenna rotates in a full circle. The rotation
occurs at an elevation angle above the x-y plane of the Emitter Frame of Reference. The
Emitter Beam Reference (or positive y-axis) defines the starting position of the scan at time
zero. Figure 12 depicts a conceptual view of a circular scan while Table 4 lists the additional
input values that are required to model the scan.
Name
Units
Table 4. Circular Scan Parameters
EAG Object
Range Range
Pin Name
Min.
Max.
Scan Period
ms
Scan Period 1
10
100,000
Elevation
deg
Scan Elevation
-90
+90
Description
Period of one full rotation of the
antenna.
Elevation of the scan.
Figure 12. Circular Scan
Given the Scan Period (), the Elevation (), the current time (t), and the initial time the
model started emitting (t0), the time within the cycle is determined by:
ti = (t - t0) mod 
Since the pattern width is a full circle:

The rate of rotation of the antenna is calculated as:

Therefore the position of the antenna at any given time is:


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