User`s guide

13 DSP Blockset 4.1 Release Notes
13-4
IFFT Block
•You can now set the block's twiddle factor computation method as in the FFT
block (see the earlier FFT block enhancement description).
•A new option lets you provide inputs in both linear and bit-reversed order.
Using inputs in bit-reversed order reduces block computation time by
eliminating the initial input data scrambling step.
•You can now explicitly specify conjugate-symmetric input signals to
significantly increase processing efficiency and to get a real-valued output
signal.
•You can now skip normalization by the IFFT length, N, when you do not need
to output a normalized signal, increasing processing efficiency.
•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 IFFT block reference page.
Magnitude FFT Block
•You can now set the block to compute the magnitude FFT or magnitude
squared FFT
•The block uses the new, more efficient FFT block algorithms.
For more information, see the Magnitude FFT block reference page.
Overlap-Add FFT Filter and Overlap-Save FFT Filter Blocks
By using the enhanced FFT and IFFT blocks, the Overlap-Add FFT Filter and
Overlap-Save FFT Filter blocks are more efficient. (Both blocks now skip data
descrambling and scrambling operations by processing data in bit-reversed
order, and use specialized, more efficient algorithms for real-valued input
signals.)