74 Xilinx Development System
Xilinx System Generator v2.1 Reference Guide
Block Parameters Dialog Box
The block parameters dialog box can be invoked by double-clicking the icon in your
Simulink model.
Figure 3-49: DDS block parameters dialog box
Parameters specific to the DDS block are:
• Function: specifies the block output to be sine, cosine, or both.
• Negative Sine: when checked, the sine output is negated.
• Negative Cosine: when checked, the cosine output is negated.
• Output Width: number of bits in the output signal; value must be between 4
and 32 inclusive.
• Lookup Table Input Width: specifies the number of address bits into the
Sin/Cos Lookup Table; value must be at least 3. It cannot exceed the lesser of the
accumulator width and 16 (if block RAM is used), or 10 (if distributed RAM is
used).
