User's Manual

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Version 1.1 SDT_ARK6_User_Manual_ENG_vATSC Page 68 of 206
5.8.2 Non Linear Precorrection
Click on AM/PM button icon, highlighted in the next figure, to access the pre-correction window.
Figure 28. AM/PM Precorrection
Two main actions are possible in this section:
 AM/AM and AM/PM curve drawing: used to change the AM/PM pre-correction coefficient.
 AM/PM pre-correction files management: used to open or save AM/PM pre-correction setting
file.
 AM/AM and AM/PM curves are specific for each power range of each output channel.
The two curves are used to calculate the AM/PM pre-correction coefficients. The curves are drawn by
the interpolation of 1024 points referring to the points inserted and using a linear or polynomial
interpolation algorithm.
Knob points can be added with a left-click of the mouse on the grid and deleted with a right-click, drag
and move a point to change the curve.
Each coefficient variation, due to curves change, is saved in the FPGA “runtime” memory registers and
dynamically changes the device’s output.
The tool is prevented to send an “overflowing” amount of data to the device: curve changes will be
applied only when the mouse button is released.
In the module grid, the red curve is used to monitor the current module curve calculating and saving.
The last saved coefficients are locally downloaded from the FPGA runtime memory registers in order to
redraw the curve.