Define PRF Pie Slices (PRFSECT)
This command supplements the SETPWF command and allows an alternate trigger PRF to be generated within prescribed AZ/EL sectors. See Set pulse width and PRF (SETPWF).
Up to 8 trigger sectors can be defined by invoking PRFSECT for each separate region. The trigger pattern then automatically changes when the antenna enters any of these regions, but the timeseries data remains continuous and uninterrupted throughout each change. PRFSECT allows a complete volume scan to run with PRFs that have been optimized to the radar echoes in all directions. Note the following caveats should be observed:
- Dual-PRF unfolding cannot work properly at PRF sector boundaries. We recommend not using Dual-PRF and PRFSECT at the same time.
- When PRF sectors are used in conjunction with angle sync'ing, it is best to set the PRF sector boundaries at the midpoint between individual sync angles. This prevents the PRF seam from bobbling between two adjacent sync angles.
The SETPWF opcode deletes any alternate sectors that have been setup so far. Thus, you can only use the PRFSECT command after SETPWF has established the pulse width and default trigger rate for the entire AZ/EL scan volume.
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
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| | 0 0 0 1 1 0 0 1 1 1 1 1 | Command
|---------------|------------------------------------------------| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
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| |Sector | Input 1
|----------------------------------------------------|-----------| Sector selects which sector
number is defined to have an alternate trigger pattern. This is an arbitrary index from
0 ... 7.
The following 4 arguments define a solid sector in azimuth and elevation within which the alternate trigger pattern is used in preference to the default (SETPWF) pattern. When the current AZ/EL angle pair is contained in more than one defined sector, the trigger pattern from the lower numbered sector is used.
 | The sector bounds are inclusive, that is, they include the upper/lower AZ/EL boundaries themselves. This convention makes it simpler to define several contiguous regions without generating slivers in between. |
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
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| Lower AZ (Binary angle) | Input 2
|----------------------------------------------------------------| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
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| Upper AZ (Binary angle) | Input 3
|----------------------------------------------------------------| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
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| Lower EL (Binary angle) | Input 4
|----------------------------------------------------------------| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
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| Upper EL (Binary angle) | Input 5
|----------------------------------------------------------------| The following arguments specify a trigger period in the same manner as the optional form of the SETPWF command.
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
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| Lower 16–Bits of 32–Bit Trigger Period in Nanoseconds | Input 6
|----------------------------------------------------------------| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
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| Upper 16–Bits of 32–Bit Trigger Period in Nanoseconds | Input 7
|----------------------------------------------------------------|