User`s guide

New Features
13-3
The Digital Filter Design block replaces many of the blocks from DSP Blockset
4.0 (Release 12). For details, see “Changes to Filtering Block Libraries” on
page 13-9.
Major Individual Block Enhancements
The following sections summarize the major individual block enhancements for
DSP Blockset 4.1:
•“FFT Block”
•“IFFT Block”
•“Magnitude FFT Block”
•“Overlap-Add FFT Filter and Overlap-Save FFT Filter Blocks”
•“Random Source Block”
•“Sine Wave Block”
•“Unwrap Block”
•“Window Function Block”
FFT Block
•You can now set the block to compute twiddle factors by table lookup or by
calling trigonometric math library functions. In table lookup mode, the block
precomputes and stores a table that you can optimize for memory or speed.
For an N-point FFT, a table optimized for speed yields a length-3N/4 table,
and a table optimized for memory yields a length-N/4 table.
•A new option lets you set the block to output in bit-reversed or linear order.
Outputting in bit-reversed order reduces computation time by eliminating
the output data descrambling step.
•The block processes real-valued inputs using more efficient algorithms.
•The block generates smaller Real-Time Workshop C code with improved
run-time efficiency through use of in-place algorithms.
•The block now supports single-precision (32-bit) floating-point input and
output signals (in table lookup mode) for both simulation and Real-Time
Workshop C code generation.
For more information, see the FFT block reference page.