EP1S20F672C7N Datasheet, PDF (574/864 Pages) List of Unclassifed Manufacturers – Stratix Device Handbook, Volume 1

Operational Modes
Figure 6–13. Complex Multiplier Implemented Using Two-Multiplier Adder
Mode
18
18
A
18
C
18
B
18
D
18
A
18
D
18
B
18
C
DSP Block
36
37
Subtractor
36
A×C-B×D
(Real Part)
36
Adder
37
A×D+B×C
(Imaginary Part)
36
Four-Multiplier Adder Mode
In the four-multiplier adder mode, which you can use for 1-dimensional
and 2-dimensional filtering applications, the DSP block adds the results
of two adder/subtractor/accumulators in a final stage (the summation
block).
1 You can only use the adder block if it follows multiplication
operations.
9- & 18-Bit Summation Blocks
A single DSP block can implement one 18 × 18 or two 9 × 9 summation
blocks (see Figure 6–14 on page 6–25). The multiplier product widths
must be the same size.
6–24
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005